All RAD physics question
32. For a water wave traveling at 3 meters per second, and l = 2 meters, the frequency is:
1.5 hertz
8. For a half-value layer test, the following exposures are measured by an ion chamber with increasing amounts of aluminum absorber placed in the beam as indicated below; What is the HVL for this x-ray beam? 0 mm Al: 180. 1 mm Al: 100 mGy. 2 mm Al: 60 mGy. 3 mm Al: 30 mGy
1.5 mm Al
41. Which of the following numbers is the same as 10 raised to the minus 6th power?
1/10,000,000
16. If one minute of a clock is 1 cycle of a secondhand movement, what is the frequency of each second of movement?
1/60 hertz
17. The contrast generated by a fluoroscopic image intensifier tube typically deteriorates at a rate of ______% per year.
10
State limit for exposure is:
10 R/min at 30 cm from Image intensifier
37. In most of Europe, the electricity supplied is 50 Hertz AC. How many times does the current stop and start in one second?
100
40. According to the diagram, what is the flux gain of this image intensifier tube?
100
55. Approximately how many centimeters is the standard distance of the x-ray tube above the table in the United States?
100
4. For DR, the size of the individual detector elements (dexels) currently used is closest to:
100 microns (1/10th mm)
Binary code for the decimal number 18 is?
10010
26. Plank's constant times the speed of light is 12.4 when solving for wavelength in angstroms from energy in kilovolts. If the very shortest wavelength in an x-ray beam is 0.11 angstroms, what is the kVp of this x-ray beam?
113 kVp
19. In the digital age, anatomy smaller than ___ cm should no longer be radiographed using conventional grids.
13
16. The area of a 30 cm circular input phosphor is approximately 707 square centimeters. The area of a 2.5 cm output phosphor is about 5 square cm. For this image intensifier, the change in fluoroscopic image brightness from minification gain alone would be:
141 times brighter
15. Any change of _____ or greater will require a technique adjustment in order to maintain the level of radiation exposure:
15%
The third "shell" outward from the nucleus can never, under any circumstances, hold more than _____ electrons.
18
14. For a 180 cm (6 ft) tall person, the distance from fingertip to fingertip with both arms outstretched is about:
180 cm (72")
13. It is recommended for completeness that the torso procedures on a technique chart be organized into columns for every _____ cm change in part thickness
2
17. An SID of 180 cm is used. The second set of shutters in a collimator is opened 6 cm, and the field size at image receptor plate measures 24 cm. What is the distance from the focal spot to the second set of shutters in the collimator?
45 cm; 180/x=24/6; 180 X 6=x X 24; 1080=24x
62. In the illustration seen below, if a hospital bed is elevated 45 degrees during a mobile AP Chest x-ray, then the X-ray tube should be angled___ from the vertical to maintain a perpendicular relationship with the imaging plate (IP).
45 degrees cephalad
49. The secondary coil of a transformer has 20,000 turns; the primary coil has 500 turns. If 120 volts is supplied to the primary coil, what will be the resulting voltage in the secondary coil? 20,000/500=X/120 2,400,000=500X
4800 volts
What is the atomic number for iodine?
53
69. Radiographers should move___ away from the patient prior to making the exposure.
6'
What was the total average annual effective dose from natural background and human-made radiations combined as of 2006?
6.3 mSv
37. Advantages of the flat panel detector over the conventional image intensifier include: a. Linear response to radiation b. Less sensitivity to local magnetic fields c. Less radiation to the patient
All of the above; Linear response to radiation b. Less sensitivity to local magnetic fields c. Less radiation to the patient
Which of the following x-ray procedures increases the radiographer's risk of exposure to ionizing radiation? 1. Mobile C-arm fluoroscopy 2. Interventional procedures that use high-level-control fluoroscopy 3. Mobile radiographic examinations
1, 2, and 3; Mobile fluoro, Interventional, Mobile x-rays
Some of the advantages of the optically luminescence dosimeter are: 1. Can be used for up to 1 year 2. Lightweight, durable, and easy to carry 3. Integrated, self-contained, preloaded packet
1, 2, and 3; up to 1 year, lightweight, preloaded packet
52. In terms of radiation safety, who should be selected to hold a neonatal patient for a mobile AP and lateral chest x-ray? Best choice:1 Worst choice: 4 1. A 30 yr old pregnant pediatric nurse. 2. A 56 yr old pediatric nurse 3. A 25 yr old pediatric nurse 4. A 25 yr old pregnant radiographer
1. A 56 yr old pediatric nurse 2. A 25 yr old pediatric nurse 3. A 30 yr old pregnant nurse 4. A 25 yr old pregnant nurse
8. Modern mobile radiographic units possess:
A flat panel detector for image review
6. Anything that exerts a "push" or "pull" such that it can cause a change in the motion of another body may be described as:
A force
41. A p-type transistor and an n-type transistor are stacked together to form an electronic gate called a(n):
CMOS
23. Should be repositioned after consulting a nurse or physician:
CVP line
What is the chemical symbol for calcium:
Ca
36. Which of the following, when increased, causes the space charge around the filament to expand:
mA station
12. The unsharpness in an image is produced by all of the following except:
mAs
19. Operating the image intensifier tube in the _______ mode can help reduce pincushion distortion:
magnified
2. Sorting an image by the location of its pixels results in a(n):
matrix
9. For digital imaging, each frame displayed consists of a discrete number of rows and columns of picture elements called the:
matrix
10. During chest radiography, if the exposure time is decreased, image sharpness of detail will:
may be affected indirectly, but is not directly controlled by it
19. Sound waves are a good example of radiation as:
mechanical waves in a medium
16. Within the x-ray machine circuit, a meter placed in series in the secondary side of the high-voltage transformer most likely measures:
milliamperes
24. Mathematically, the ratio of an image's recorded contrast to the real anatomical structure's subject contrast defines the ________ for the imaging system:
modulation transfer function
45. True saturation presents an area of the image with:
no details at all present
36. Generically, each user-accessible device within a digital imaging network is referred to as a(n):
node
25. With all other factors unchanged, if grid ratio is increased, magnification of the image would:
not change at all
26. With all other factors unchanged, if grid ratio is increased, penetration of the x-ray beam would:
not change at all
9. With all other factors unchanged, if mAs is increased by 50%, subject contrast in the remnant beam will:
not change at all
3. The end product(s) of the photoelectric effect is/are:
one ejected electron, and an orbital vacancy
The luminance of a collimator light is determined by measuring the concentration of light:
over a particular field of view
25. Exposure techniques that are pre-programmed in the x-ray machine should be:
over-ridden and modified on occasion according to the professional judgment of the radiographer
2. The rule for adjusting tube-to-tabletop distance for x-ray beam angles is used to maintain the:
overall exposure at the image receptor plate
6. Additional scatter radiation increases:
overall exposure at the receptor plate
13. The preferred method for demonstrating air fluid levels during mobile radiography is to make sure that the:
patient is sitting fully erect; x-ray beam is perpendicular to the receptor.
5. Lead is commonly used as shielding against x-rays because of its very high atomic number. This high Z number makes it most likely that x-rays passing through lead will interact by:
photoelectric interaction
12. Subject contrast within the remnant beam of x-rays is directly proportional to the:
photoelectric/Compton ratio
24. The device (provided by many manufacturers of display monitors) designed to directly measure luminance, or the light intensity emitted from a display monitor, is the:
photometer
6. The ability to distinguish two adjacent details as being separate and distinct from each other defines image:
resolution
11. The AEC can be rendered unreliable if the speed of the image receptor used is so fast that the resulting exposure times become shorter than the required:
response time
8. In an induction motor, only the _____ rotates.
rotor
45. A network ______ connects two or more computer networks:
router
35. For CR systems, an upper limit on spatial resolution is imposed by the:
sampling frequency of the CR reader
14. The difference between how physicists measure image qualities and how radiographers define clinical image qualities is primarily a matter of:
scale
3. In the 1980s, the first clinically useful DR system consisted of a bar of large detectors connected to photomultiplier tubes, which swept across the field area during exposure. This system was called:
scanned projection radiography
4. All of the following are components of image penumbra except:
scatter radiation fog
16. Which of the following features suppresses image noise (mottle) with an attendant slight decrease in contrast throughout the image?
smoothing
28. When 65 kVp is applied to a tungsten-target x-ray tube:
some x-ray photons produced (projectile electrons) may have 65 kV of energy
5. What is the process of "boiling off" electrons from the x-ray tube filament called?
thermionic emission
39. Because some quantum mottle is beginning to appear on images from a particular radiographic unit, it is desired to increase the amount of exposure reaching the AEC detectors. This can be achieved by re-setting which of the following:
the "density" control
11. In the active matrix array of a DR image receptor, what device controls the order in which the dexels are read out by sending a bias voltage down the gate lines to each TFT:
the address driver
51. Which of the following increase the conversion efficiency of a CR phosphor plate:
the chemical compound used as a phosphor
19. Which of the following is determined by the computer by finding the mid-point between SMIN and SMAX in the main lobe of the generated histogram for the image?
the exposure indicator
14. Which of the following would be defined as the area of heat dispersion on the x-ray tube anode:
the focal track
26. Which of the following describes illuminance:
the intensity of light from other sources striking a surface
5. The pixels of a liquid crystal display (LCD) screen are made up of:
the intersections of transparent, flat wires
65. The following illustration, Graph B indicates that:
the kVp decreases during the time of exposure
31. The efficiency and life span of the filament wire is improved by the addition of:
thorium
14. A radiograph demonstrates a loss of exposure toward only one side of the image. The most likely cause was a(n):
tilted receptor plate with a grid
11. Which of the following is least effective in producing subject contrast?
tissue density
12. Which of the following is most associated with the very first generation of computers?
vacuum tubes
4. A histogram is the result when a digital image is sorted by the:
values contained by each pixel
52. An MRI unit determines the location of a particular body structure by:
varying the magnetic field strength to emit radio waves with different frequencies
7. All of the following are DICOM commands except:
window level
3. In generic digital imaging terms, the range of the image gray scale is called:
window width
23. The general term for making changes in the brightness and contrast of a digital image is:
windowing
12. Which of the following is the best way to improve the statistical quality of the fluoroscopic image, reducing quantum noise, is to increase the:
x-ray tube current (mA)
Which of the following is not a form of naturally occurring radiation from radioactive nuclei?
x-rays
9.The focal spot is directly responsible for the production of geometrical penumbra in the image because:
x-rays can be emitted at various angles from different points within it
In the event that a pregnant patient is inadvertently irradiated:
the radiologic physicist should perform the calculations necessary to determine fetal dose.
18. The effects of field size limitation (collimation) upon the subject contrast carried within the remnant beam signal are best attributed to their impact on:
the relative proportions of scatter and primary radiation in the remnant beam
24. Photostimulated luminescence refers to the process by which:
the trapped energy of the electronic latent image is released as visible light
19. Solve for X: X + 22 = -8
X= -30
19. In an atom, when an electron drops down from the L shell to the K shell:
a photon will be emitted
7. When a bremsstrahlung x-ray is produced:
a projectile electron loses energy
4. What characterizes Compton scattering:
a recoil electron
30. Which of the following connect wide area networks (WANs) to the internet:
a router
6. If the projected image of an object is already being distorted from being off-centered in the x-ray beam, which of the following would make that distortion appear worse:
a short SID
9. The AEC system on most mammography machines utilizes ______ radiation sensitive detector located ______ the cassette.
a single; behind
21. In the x-ray tube, off-focus radiation can be produced from: a. the anode disc b. the glass envelope c. the anode stem
any of the above; the anode disc, the glass envelope, the anode stem
10. An anatomical LUT is a table generated by applying a(n) ________ to the incoming data set: a. intensity transformation formula b. algebraic formula c. algebraic function curve
any of these; intensity transformation formula, algebraic formula, algebraic function curve
15. Within a PACS server, storage using jukeboxes in a separate location would be classified as _________ storage:
archive
39. The molecules of a gas:
are not held in fixed positions relative to each other
In photoelectric absorption to dislodge an inner-shell electron from its atomic orbit, the incoming x-ray photon must be able to transfer a quantity of energy:
as large as or larger than the amount of energy that binds the electron in its orbit
39. Which of the following may use a bar code from the CR cassette:
assigning an image to a study
13. Bone shows up with high contrast on a radiograph primarily because of its:
atomic number
10. The reduction in the original number and energy of x-ray photons as they interact with atoms within the patient is called:
attenuation
5. Any number can be converted into scientific notation without even moving the decimal place
by simply adding the phrase: "X 10 to the 0"
30. The brightness of the image-intensified fluoroscopic image varies _____ the kVp.
by the fifth power of
3. The validity of technique charts and technique guidelines is directly dependent upon proper:
calibration of equipment
11. With digitized imaging, the use of a variable-kVp, high-kVp approach to radiograph technique:
can save patient exposure
The radiation dose absorbed by an organ such as bone marrow:
cannot be measured by a direct method; it can only be estimated.
18. Which of the following is used only with focused grids?
canting
28. The photoelectric interaction is essential not only to the production of subject contrast in the remnant x-ray beam, but also to the:
capture of the image by the image receptor
22. The mobile C-arm fluoroscopy unit requires the use of a dedicated or special surgery table. Which type of table significantly reduces skin entrance exposure to the patient?
carbon fiber
33. Most of the heat energy produced in an x-ray tube during an exposure is released by:
conduction
7. Electrical fields are always created inside:
conductors in moving magnetic fields
34. With CR systems, the use of left and right lead markers on the original exposure:
continues to be recommended
22. For the Fuji CR system, changing the "L" number adjusts the:
contrast of the displayed image
13. In indirect conversion DR systems, the dispersion of light emitted from molecules of cesium iodide is reduced by using:
crystalline phosphor structure
9. The effect of electrical charges in motion through a conductor is referred to as:
current
25. Using proportional anatomy, when changing from a PA skull projection to a lateral skull, adjust overall technique as follows:
cut to one-half
3. If overall exposure at the image receptor plate was maintained by cutting the mAs from 60 to 15, the SID must have been:
cut to ½
6. Flat-field uniformity corrections are necessitated because of all of the following except:
data clipping
28. Condensation results in a(n):
decrease in potential energy
5. As x-ray beam energy (kVp) increases, the absolute amount of scattered radiation produced within the patient:
decreases
25. As the kVp is increased, the occurrence of Compton interactions:
decreases very slightly
Whenever scattered radiation decreases, the radiographer's exposure:
decreases.
43. For digital imaging systems, which of the following presents the greatest risk to image quality when performing a bilateral projection of both knees:
exposure field recognition error
13. Anything that can result in a histogram error can result in:
exposure indicator error
9. Mottle is likely to appear in the computerized image any time the:
exposure indicator is very low
28. Which of the following is not a variable affecting subject contrast in the remnant x-ray beam?
focal spot
26. As mA increases, it can have an indirect effect on increasing image blur due to its impact on:
focal spot blooming
15. Grids should generally be used:
for anatomy thicker than 13 cm
14. The size of the effective or projected focal spot is its size as measured:
from the viewpoint of the image receptor
Digital mammography units with the ability to enhance contrast with image gray-level manipulation offer:
improvement for patients with dense breasts.
1. Which of the following is not a cause of scatter radiation?
increased mAs
31. Most of the energy from the electron stream is dispersed as ___________ when excited outer-shell electrons in the atoms of the anode fall back into their orbits:
infrared rays
1. The mAs should be considered as the primary control for what aspect of the remnant x-ray beam?
intensity
29. A universal serial bus (USB) port is a type of:
interface
8. The ideal degree of brightness for any image would be a(n) _______ level:
intermediate
24. When the SID is changed, to solve for which new mAs setting will maintain exposure to the image receptor, use the:
inverse square law
16. The types of radiation that are biologically harmful are those which are directly capable of:
ionizing atoms
20. One correct interpretation of Einstein's famous equation "E = mc2" is that:
it takes an enormous amount of energy to create a very small amount of matter
15. The generic unit of energy is the:
joule
A patient is positioned in the LPO oblique to obtain a Y projection of the right shoulder as seen in the image below. Which of the following changes in technique will restore the loss of sharpness created by the large OID?
6 mAs, 2.0 mm FS, 0.6 mm FS, 40" SID, 80 kVp
4. The binary number 0111110 translates to the decimal number:
62
6. Even for body torso procedures, an "average" technique will be usable without modification for what percentage of all adult patients?
67%
67. Which grid type would permit wide exposure and centering latitude and would therefore be preferred for mobile radiography?
6:1
57. During optimal mobile radiography of the chest, the recommended SID is _____ inches.
72
2. The value 0.72 expressed as a percentage is:
72%
40. What is the atomic number for tungsten?
74
10. An x-ray beam has a half-value layer of 2 mm Al. If 4 mm of aluminum filtration is added at the collimator, the intensity of the beam will be reduced to:
75%
35. Even with the most sensitive digital imaging systems, true saturation requires at least _____ times the normal exposure to occur:
8
9. Regarding radiographic technique, a modern battery-powered constant-potential generator (CPG) mobile unit requires at least _____ when compared to a 3-phase, 6-pulse fixed unit in the imaging department.
8 kVp less
6. The advantage to using low kVp in mammography is its ability to produce: A very low energy x-ray beam. High radiographic contrast. A soft x-ray beam. All of the above
All of the above; Low energy, High contrast, Soft beam
13. Which of the following are functions of the "rotor" switch before exposure can be made: a. Spin the anode disc up to full speed rotation b. Engage the oscillating grid for bucky procedures c. Bring the x-ray tube filament up to full temperature for the mA station selected
All of the above; Spin the anode disc up to full speed rotation, Engage the oscillating grid for bucky procedures, Bring the x-ray tube filament up to full temperature for the mA station selected
25. Using a non-grid approach for mobile and trauma procedures helps prevent: a. Unnecessary patient dose b. Grid cut-off c. Problems adapting positions
All of the above; Unnecessary patient dose, Grid cut-off, Problems adapting positions
1. An object can become charged by: a. electromagnetic induction b. contact with a charged object c. friction
All of these; electromagnetic induction, contact with a charged object, friction
59. The Nyquist criterion states that to prevent aliasing, the sampling rate must be _____ the spatial frequency of the image:
At least twice
11. An exposure time of 1/8 second is equal to which decimal equivalent:
0.125 ses
16. Typical x-ray beam divergence at 100 cm SID is _______ per centimeter in any direction away from the CR:
0.7 degrees
5. If an extremity must be radiographed at 50 inches (125 cm) SID because of traction devices, use _________________ than the usual 40-inch (100-cm) technique:
1 and ½ times more (or one "step" in mAs more)
16. The increased contrast resolution of digital imaging systems allows demonstration of tissue with an inherent subject contrast as low as:
1%
27. Low-resolution display station screens contain how many pixels?
1,000 pixels
Normally, mutations in genetic material occur spontaneously, without a known cause. A genetic disorder is present in approximately _______ of all live births in the United States.
10%
18. A body part that is 5 cm thinner than average requires ____ for radiographic technique.
15% less kVp
27. If the measured contrast between two anatomical structures in an image is 1, and the subject contrast between the two real structures has a relative value of 6.2, what is the modulation transfer function for this image?
16%
34. Preferred energy range of x-ray photons:
17 to 20 kev
An atom has an A-number of 30 and 12 neutrons in its nucleus. What is its Z-number?
18
The element krypton (Kr) has 36 electrons arranged in 4 "shells". What is the maximum electron density of krypton's " M- shell"?
18
In what year were x-rays discovered?
1895
39. A fluoroscope is operated at 95 kVp and 2 mA. What is the power consumption at this technique?
190 W
10. What is the latest date for which the medical application of rare earth fluorescent screens, ultrasound, CT, MRI, CR and DR have all occurred:
1996
15. At the most microscopic level, an image detail has ______ aspects.
2
38. An x-ray machine has a 30 kilowatt (kW) generator. If the maximum kilovoltage available is 150 kV, what will be the available tube current?
200 mA
13. For CR, DR, CT, MRI, NM and US units, images are usually erased ______ after acquisition:
24 hours
20. Most AEC "density" controls extend or shorten the exposure time in increments of:
25%
37. The "density" controls for most AECs adjusts the pre-set exposer level in increments of:
25%
10. In a typical x-ray tube operated at 90 kVp, the most abundant x-ray produced would be:
30 kV bremsstrahlung
18. Upon angling the x-ray beam 20 degrees from vertical with an image receptor plate on the tabletop, what must the tube-to-tabletop distance be in order to maintain a SID of 40"?
36 inches
According to the Environmental Protection Agency (EPA), radon levels in homes should not exceed what level?
4 pCi/L
26. How many square centimeters are there within 4 square meters?
400 cm2
7. In terms of overall exposure to the imaging receptor, which of the following techniques is not roughly equivalent to the other four:
400 mA 0.l7 sec., 80 kVp
23. What is the "long-hand" expression for 4.2 X 10(4)
42,000
Annual allowable limit for occupational workers:
5,000 mRem
41. According to results of the bone densitometry examination seen below, which statement best describes the patient?
52 year old female
Determine the cumulative effective dose (CumEfD) limit to the whole body of an occupationally exposed person who is 52 years old.
520 msv
26. When using automatic exposure control (AEC), which of the following would result in over exposure to the image receptor plate?
Wrong bucky activated
2. If a department chooses to operate their CR or DR system at the 200-speed class, what general adjustment in techniques must be made in changing from 400-speed rare earth screens:
a two-fold (2X) increase overall
5. Mottle in a CR or DR image can result from: a. insufficient kVp b. insufficient mAs c. improperly calibrated AEC
all of the above; insufficient kVp, insufficient mAs, improperly calibrated AEC
3. In radiography, which of the following are mathematical? a. repeated exposures b. image contrast c. image detail
all of the above; repeated exposures, image detail, image contrast
8. If the long axis of an object lies at a 25-degree angle from the film, and you cannot change it, you should:
angle the CR 12.5 degrees to the image receptor plate
17. The patient is supine with the mouth opened for a projection of the odontoid process. The SID is 100 cm. If the CR is vertical and centered 3 cm caudal to the correct centering point on the odontoid process, the x-ray actually passing through the process will be:
angled 2 degrees cephalic
29. Histogram analysis errors:
are not necessarily related to the radiographic technique used
1. In computer terminology, a single binary digit is referred to as a:
bit
22. Unpopular and nearly obsolete type of generator for mobile units:
capacitor discharge
3. Which of the following should always be optimized at an intermediate or medium level:
contrast
17. Which of the following would result in a displayed digital image which is brighter:
decreased window level
12. The direction of electrical current flow is traditionally defined by electricians as the:
direction of movement of positive charge
12. Mathematically, the contrast present in any radiographic image is best thought of as the _____ between two adjacent areas of different tonal value (density):
divided ratio
10. Exactly doubling the focal spot size will cause the spread of penumbra to:
double
18. The use of low-pass filtering (smoothing) will tend to:
eliminate the appearance of high-attenuation artifacts from the image
49. A reflective backing in a CR phosphor plate improves its:
emission efficiency
46. In the digital age, the main role of radiographic technique is to:
ensure that adequate signal reaches the detector
19. Ohm's law states that the electrical current:
equals the voltage divided by the resistance
3. In the basic x-ray machine circuit, which of the following is normally located between the autotransformer and the step-up transformer?
exposure timer circuits
23. Which of the following x-ray generators produces an average kV at about 1/3 of the set kVp:
fully-rectified single-phase
9. At the edges of an image, scatter radiation:
has no effect on penumbra
22. In comparing three-phase x-ray generators to single-phase generators, the three-phase generators produce:
higher effective mA
6. On most digital systems, image brightness can be increased by:
holding the mouse button down and moving the cursor to the right
16. Which of the following is a primary advantage of direct-conversion DR receptors over indirect-conversion systems?
improved resolution
19. When one component fails in a storage area network, in order to prevent breaking connections between other components, all devices are connected:
in parallel
11. With all other factors unchanged, if an object is tilted in relation to the receptor plate, the image shape distortion will:
increase as a direct result
24. Regarding the exposure indicator for CR and DR images, the use of automatic exposure control (AEC) makes:
it even more important for radiographers to monitor the exposure indicator
14. Which of the following has energies measured in the range of 2 to 3 volts:
light waves
16. Which of the following is used properly only in conjunction with measuring calipers?
manual technique charts
8. The extensive, detailed information stored "behind" every image is its:
metadata
5. When using automatic exposure control, if too high an mA station is used for the particular patient and body part, the patient will receive excessive exposure because of:
minimum response time for the AEC
15. The anode material of choice for mammography machine is:
molybdenum
12. With all other factors unchanged, if the CR is off-centered to a flat object which is parallel to the image receptor plate, image magnification will:
not change at all
13. With all other factors unchanged, if the focal spot size is decreased, magnification in the image will:
not change at all
17. With all other factors unchanged, if kVp is decreased, image sharpness of detail will:
not change at all
6. Modern x-ray collimators have two sets of shutters. The second (lower) set is actually a patient protection device which reduces:
off-focus radiation
1. Which of the following is not a principle of scientific method:
once proven to be fact, a scientific law should never be revised
3. In algebra problems, the first operation is always to calculate the:
parentheses
39. All of the following are components of a flash memory cell except:
pits and lands
8. A small point within an image that has been assigned a particular gray shade or brightness level is called a:
pixel
15. In any digital image, the distance from the center of one pixel to the center of the next adjacent pixel is the:
pixel pitch
28. The formula, 0.7 X mA X kVp /1000 gives us the:
power rating for a single-phase generator
10. The only disadvantage to using the same optimum mA station throughout a particular radiographic procedure is the:
probability of patient motion
40. In any CR system, underexposure causes visible ______ in the displayed image:
quantum mottle
17. All other factors equal, when mAs is reduced, the photoelectric/Compton ratio will:
remain unchanged
35. When a patient is rolled up onto her side, it takes longer for the AEC to shut off the exposure because:
remnant beam exposure rate is reduced
28. The material often added to a rotating anode disc to reduce surface defects and improve rotational balance is:
rhenium
9. The filament current is applied to the x-ray tube filament each time the:
rotor switch is depressed
9. Which of the following is not a form of image noise:
signal
16. The mathematical measure of overall visibility of information contained in an image is:
signal-to-noise ratio
33. When the correct level of exposure is reached, an automatic exposure control (AEC) circuit breaks the main circuit of the x-ray machine. To open a switch in the main circuit, the AEC uses a(n):
surge of electricity to an electromagnet
34. The ability to send radiographic images from one place to another over phone lines, cables or satellite systems is known as:
teleradiology
16. Digital receptor with electrical cord:
tethered detector
22. The beam spectrum for characteristic x-rays principally depends on:
the anode target material
20. The principle limiting factor for the perception of contrast in an analog imaging system is:
the inherent poor contrast enhancement of analog systems
25. In a common circuit, the effect of the electrical current travels at:
the speed of light
15. When the exposure switch is engaged, which electrical current is applied to the filament in the x-ray tube?
the tube current
5. All of the following are true of capacitor discharge units except:
they are quite popular due to their small size and weight as well as output
2. Within the automatic exposure control circuit, which of these is placed in the circuit immediately following the capacitor?
thyratron
3. For an AEC circuit, which of the following electronic devices corresponds to the "density" control on the console?
thyratron
20. Reduction of the focal spot size can be accomplished by:
using a smaller filament
32. Preferred filter material:
Beryllium
7. I/O devices employed in radiologic imaging include all of the following except:
CD
27. When using automatic exposure control (AEC), which of the following would result in under exposure to the image receptor plate?
Detector cells not fully covered by the tissues of interest.
19. Mathematically, subject contrast in the remnant beam signal is best thought of as the ___ between two adjacent areas of different x-ray intensities:
Divided ratio
The CareStream™ CR system uses a logarithmic scale for its exposure indicator, with an ideal index number of 2000. If a radiograph is produced with an exposure index of 1700, what change in radiographic technique would bring it back to the ideal amount?
Double
50. When a substantial change in approach to technique is made, which of the following will need to be changed:
EIT (target exposure indicator)
42. Instructions designed to only be read and followed, but can be updated if special equipment or downloads are used, would most likely be stored as ________ memory:
EPROM
43. On a liquid-crystal display (LCD) monitor, each intersection of two flat, transparent wires constitutes a:
Hardware pixel
51. In healthy adults, peak bone mass occurs:
In their twenties and mid-thirties
18. When it is known in advance that a large prosthesis or large orthopedic device that would absorb a lot of radiation is present within the anatomy, the best approach for radiographing this patient is to use:
"manual" technique, with the AEC off
15. To obtain 20 mAs using the 400 mA station, use an exposure time of _____ seconds.
0.05
22. If the spatial frequency in the remnant x-ray beam is 5 LP/mm, and the hardware pixels of a digital imaging receptor plate are 0.2 mm in size, what is the smallest object that can be resolved by this system?
0.2 mm
38. What is the "soft" pixel size for a 205 mm (FOV) image displayed on a monitor screen with a 1024 X 1024 matrix of hardware pixels?
0.2 mm
100 Rad:
1 Gry and 100 Rem=1 Sievert
62. Subject contrast is related to: 1. Differential tissue absorption 2. Atomic number of the tissue being traversed 3. Proper regulation of milliampere-seconds
1 and 2 only, Differential tissue absorption, Atomic number of the tissue being traversed
Specific area shielding may be selectively used during some x-ray procedures to protect which of the following? 1. Lens of the eye 2. Breast 3. Extremities
1 and 2 only; Lens and breast
35. Which of the following will increase when a magnification mode is selected on an intensifier tube? 1. Patient exposure 2. Resolution 3. Input phosphor size
1 and 2 only; Patient exposure and Resolution
10. Which of the following is about the width of your smallest fingernail?
1 cm
Secondary radiation includes: 1. leakage radiation. 2. primary radiation. 3. scatter radiation.
1. Leakage radiation and 3. Scatter radiation only
37. What is the magnification factor for an image viewed with an image intensification tube with an input screen diameter of 26 cm that is using a 17 cm diameter area during magnification?
1.5; image size 26/object size 17
17. As a rule of thumb, a 75 cm (30") projection requires _____ technique than a 100 cm (40") projection for the same anatomy:
1/2
32. A deviation index of -3 indicates an under-exposure of _____ the ideal level:
1/2
7. If the mA is set at 100/300 and the total mAs produced is 15 mAs, the exposure time must be:
1/20 second
12. What is 8 X 10(8th) divided by 4 X 10(-2)?
2 X 10(10th)
30. The deviation index changes by minus one (-1.0) for each exposure reduction of:
20%
33. At 110 volts EMF, and a current of 5 amps, the electrical resistance must be:
22 ohms
16. The end of an extension cylinder is 40 cm from the focal spot. The cylinder has a diameter of 8 cm, and the diameter of the projected field at the image receptor plate is
24 cm. What SID was used? 120 cm; 40/8*24=120 x/40=24/8; x X 8=40 X 24; 8x=960
14. The majority of mammography machines utilize a _____inch SID.
24 to 30
25. Breast compression is applied at _____ pounds of force.
25 to 45
21. If the smallest object an imaging system can resolve is 0.167 mm in size, what is the spatial frequency for this system?
3 LP/mm
21. When a charged particle moves in a straight line, a magnetic field is:
Induced perpendicular to the particle's motion
55. How many lead aprons should be carried to a mobile radiographic examination?
Two
15. What is the chemical symbol for tungsten:
W
21. Which of the following most closely describes a radiographic viewing area with class 2 monitors, where windowing and special post-processing operations can be performed on images and saved, but where diagnostic findings are not dictated:
a technologist workstation
3. Which of the following objects, if any long axis they possess is kept parallel to the image receptor plate, will show the most shape distortion when an x-ray beam is angled against them by 25 degrees:
a thick spherical object
10. Of the following, which best represents an analog device:
a traditional screen/film radiograph
35. On a liquid crystal diode (LCD) monitor, a dead pixel is seen as:
a white spot against a black background, the size of a period in 12-point font
16. To help identify and direct information to the proper memory location, a unique identifying label called a(n) _______ is applied to it.
address
7. Shape distortion in a projected image is controlled by:
alignment
4. The molecules of a nematic liquid crystal material: a. flow like a liquid b. have a linear, thread-like shape c. tend to keep their axes aligned
all of the above; flow like a liquid, have a linear, thread-like shape and tend to keep their axes aligned
27. Which of the following bremsstrahlung could be produced from a 67-kV projectile electron? a. 14 kV b. 55 kV c. 67 kV
all of these; 14 kV, 55 kV, 67 kV
5. The video display terminal that displays information as a series of letters, numbers or symbols is referred to as:
alphanumeric display
14. Which of the following methods preserves the original data set for an image while allowing modifications in its appearance on the display monitor to be made?
alternate algorithms
Entrance skin exposure:
amount of radiation delivered to the patient's skin at the beam's entrance point. R/min. "Table-top dose"
37. As an x-ray tube ages, the glass envelope may suddenly crack (and the vacuum may be lost). What is the most likely cause for this:
arcing of the electron stream down to tungsten deposited on the window
28. As a result of rescaling a particular view, the "for processing" Q values that will be fed into gradation processing LUTs:
are always the same
14. The partial absorption of the x-ray beam as it passes through the body is best referred as:
attenuation
12. The computer distinguishes the anatomy of interest from background densities during:
automated exposure field recognition
19. For a CR image receptor plate, which of the following chemicals makes a good photostimulable phosphor:
barium fluorobromide
In a remote control fluoroscopic room where the x-ray tube is located above the patient, protective shielding should:
be placed over the patient
27. When a computer is turned on, the very first interaction is through the:
bootstrap program
15. The development of radiographic techniques should be:
by trial and error
22. Generally, anything that lengthens the gray scale within the remnant x-ray beam signal also increases:
exposure latitude
9. High-kVp techniques allow more margin for error in estimating mAs values. This margin of error is called:
exposure latitude
29. Which of the following is not a variable affecting image noise:
exposure time
9. Within a given procedure, if possible, the only variable to be changed from one projection to the next should be:
exposure time
14. X-rays, gravity, electrical charge attraction, magnetism and other radiations all follow the inverse square law because:
forces spread out over increasing areas with increasing distance
3. Sorting an image by the size of the structures within it results in a(n):
frequency distribution
7. Inverting an image top-for-bottom would be a(n) _________ operation:
global
29. Heat is defined as the flow of _____ from one substance to another.
internal energy
23. Occurrence of the photoelectric effect is ______ the set kVp:
inversely proportional to the cube of
6. Smaller focal spot sizes cause:
less blur
38. Toothpaste flows out of a tube squeezed at the far end because:
liquids cannot be compressed
10. A list of the pixel values that make up the "ideal" histogram shape for an image of a particular body part is called a permanent:
look-up table (LUT)
21. The control panel for most computerized radiographic units incorporates a:
minicomputer
In females with oogonia, the ovarian stem cells:
multiply to millions of cells only during fetal development
3. Scatter radiation is a form of:
noise
14. Segmentation failure is another term for errors in:
partitioned pattern recognition
17. For safety purposes, the kVp meter is usually:
pre-reading
7. The primary purpose of the filament current in an x-ray tube is to:
produce thermionic emission
11. In the basic x-ray machine circuit, the last electronic device through which high-voltage electricity must pass before reaching the x-ray tube is always the:
rectifier bridge
2. To increase the subject contrast in the remnant beam, you must:
reduce Compton interactions more than you reduce photoelectrics
10. For every 5 degrees of angulation placed on the CR, the tube-to-tabletop distance should be:
reduced by 2.5 cm
13. Through digital processing, additional frames for a dynamic image can be interpolated and inserted between the acquired frames to smooth out motion. For LCD displays, this is made possible by their extremely high:
refresh rates
12. For dynamic (motion) image displays, what is defined as the time required for an image display system to reconstruct the next frame?
refresh time
8. The intensity of the entire x-ray beam is doubled, such that twice as many photons pass into the patient. The ratio between the number of photoelectric interactions and the number of Compton interactions taking place will:
remain equal
8. Just as in conventional radiography, it is essential in digital radiography that the original ___ must have a high signal-to-noise ratio:
remnant x-ray beam
8. As one visually scans across an image, the abruptness with which the edges of a particular image "stop" would define the image's:
sharpness
24. In any image, the very smallest details present can be collectively represented as:
short waves with high frequencies
In the electromagnetic spectrum, higher frequencies are associated with:
shorter wavelengths and higher energies.
1. Inside the x-ray tube, the _____ is utilized.
simple induction motor
29. During the CR reading process, the direction in which the photostimulable phosphor plate moves as it is scanned is called the:
slow scan or sub-scan direction
Studies of Japanese atomic bomb survivors demonstrate that the incidence of leukemia has ______ since the late 1940s and early 1950s, and the incidence of solid tumors has continued to ______ since the late 1950s and early 1960s.
slowly declined, escalate
24. Which of the following would not be classified as a dielectric?
steel
3. For all digital imaging systems, a lower limit for exposure to the receptor is imposed by:
the appearance of mottle
2. The liquid crystal display (LCD) operates on the principle of:
the polarization of light
7. For digital imaging, if a grid is not used:
the reduced signal-to-noise ratio from poor input data can contribute to digital processing errors
23. Tissue equalization or dynamic range compression cannot improve:
underpenetrated portions of the image
Roentgen:
unit of measurement for the exposure of x-rays and gamma rays; the electric charge freed by such radiation in a specified volume of air divided by the mass of the air (coulomb/kg)
14. What is the voltage waveform for the filament current passing through the filament during an exposure:
unrectified AC
7. A premature baby has a body torso shape which is circular rather than oval in cross-section. On this patient, for radiography of the chest, when changing from the AP to the lateral projection what overall technique adjustment should be made from the AP technique?
use about the same technique
18. Using proportional anatomy, when changing from an average AP pelvis projection to an average AP lumbar spine, adjust overall technique as follows:
use equal technique
21. Which of the following is not a form of energy:
work
10. Penumbra occurs in all radiographic images because:
x-rays emanate from an area source
2. As a rule of thumb, changing from a 100 cm (40") SID to a 180 cm (72") SID will require _____ the radiographic technique to maintain overall exposure at the image receptor plate:
3X; 1/x=1002/1802; 10,000x=32,400
17. All variables affecting the acquisition and quality of a radiographic image can be categorized into one of _____ types of variables.
6
For a DR receptor plate, if the width of the individual detector elements could be reduced to 0.0833 mm (del pitch = 0.0833 mm), what spatial resolution could be achieved?
6 LP/mm
The image of an object measures 7 cm in width. The SID used was 100 cm and the object was located 13 cm above the image receptor plate. How big is the actual object?
6 cm
4. The advent of digital imaging has reduced the percentage of all repeated exposures due to improper brightness or density (too light or too dark) from approximately _____ to _____.
60%; 10%
31. When the 15% increase in kVp is applied along with a halving of the mAs, experiments confirm that the net patient exposure is reduced to about:
67%
26. In the digital age, especially for mobile procedures, where conventional grids continue to be used the recommended grid ratio is now:
6:1
6. From an original technique of 40 mAs at 98 kVp, which of the following techniques would increase subject contrast in the remnant x-ray beam while at the same time maintaining overall exposure intensity to the image receptor plate?
80 mAs at 83 kVp
The difference between beta (β) particles and orbital electrons include: A. Origin B. Energy C. Velocity
All of the above; origin, energy, velocity
14. A fluoroscopic examination is conducted using 1.5 A (amperes) of electricity. That is equivalent to _____ mA.
1500
14. For a fluoroscopic unit, regulations state that neither the length nor the width of the x-ray field shall exceed that of the visible area of the image receptor by more than:
3% of the SID
39. For CR, as a rule-of-thumb, at least _____ per cent of the receptor plate must be exposed to avoid histogram errors:
33%
10. What is the component of the x-ray machine circuit outline in red below?
Filament circuit transformer; the focal spot selector just prior to the mA selector.
43. Which of the following best describes non-volatile ROM code that is used by specific devices (such as cell phones) when the system first starts up:
Firmware
4. To make a significant increase in the intensity of the remnant x-ray beam, mAs would need to be increased by at least:
35%
At 70 kilovolts EMF and a current of 200 milliamperes, the electrical resistance must be ___ ohms:
350,000
5. The interactions between all matter in the universe are governed by ____ different forces.
4
A biologic reaction is produced by 4 Gyt of a test radiation. It takes 16 Gyt of 250-kVp x-rays to produce the same biologic reaction. What is the relative biologic effectiveness (RBE) of the test radiation?
4
9. The set kVp of any x-ray beam should not deviate by more than ____ percent from the read-out from the kVp meter:
5
15. Which of the following most likely describes the characteristics of the filament current:
5 amps at 5 volts
24. Normal attenuation of an x-ray beam through soft tissues proceeds at a rate of _____ for every 4 to 5 cm of tissue thickness
50%
Annual allowable limit for pregnant workers:
500 mRem
What is the atomic number for barium?
56
11. If the radiographer is unable to achieve a 72" SID during mobile chest radiography, an alternative distance to use is:
56"
34. Which of the following combinations of image intensifier input phosphor size and display matrix size would result in the sharpest image detail:
7-inch input phosphor, 100 X 100 pixel matrix on display
24. A gamma ray is:
A photon
28. Which of the following describes a single unit of light or x-rays:
A quantum
Which of the following will create the least electrical resistance?
A short wire with a large diameter
6. Which of the following is not an absolutely necessary condition for the production of x-rays:
A vacuum tube
2. All of the following are true of SXA scanning except: A. it used a radioactive source of iodine. B. it was restricted to the forearm. C. it employed a low energy x-ray beam. D. its development followed SPA technology
A. It used a radioactive source of iodine
43. It is clear from the illustration seen below that the patient is undergoing a DXA scan of the:
AP left hip
28. An institutions' unique way of identifying a specific procedure or exam on a particular patient is the procedure's:
Accession number
60. As the distance from the x-ray tube to the image receptor plate changes, the intensity of the radiation changes:
According to the inverse square of the distance
Which of the following must always be the first step in protection of the reproductive organs?
Adequate and precise collimation of the radiographic beam to include only the anatomy of interest
22. Which of the following is defined as "imperfections in computer reconstruction programs that lead to abnormalities in images produced":
Algorithmic noise
18. On a display monitor, by zooming in repeatedly on a high-resolution image, at some level of magnification it is certain that ________ will occur:
Aliasing artifacts
22. When iron is fabricated into a magnet, the magnetic domains:
Align
25. For a fluoroscopic unit, which of the following must be accurate to within 2% of the SID:
Alignment of the primary x-ray beam central ray
Automatic exposure control may be used when:
Anatomy is large
Which of the following affects the effective focal spot size?
Anode bevel and cathode filament size
In the element 63/29 Cu, the "29" would indicate the:
Atomic number
33. Which of the following terms best describes the partial reduction of the x-ray beam as it passes through matter:
Attenuation
50. Radiography is made possible because part of the x-ray beam makes it through the body and part of it does not. This is referred to as ________ of the x-ray beam:
Attenuation
32. For the lateral cervical spine projection, several manufacturers now provide an image control settings menu where the "underpenetrated area" area of the image (C7-T2) can be defined and corrected as a default setting for that procedure. This is actually an adjustment to the:
Brightness of a targeted area of the image
30. Who invented the first radiographic grid?
Bucky
Which of the following results in all-directional scatter?
Compton interaction
3. What component of electrodynamics is represented by the letter "I" in Ohm's Law? V=IR
Current/electric current/amps
Based on current data, which of the following would be considered a safe radiation dose for the gonads of both males and females?
0 Gyt
25. Convert 1700 ms into hours:
0.00047 hrs
8. Which of the following is a typical minimum response time for an AEC circuit?
0.01 second
19. What is the amount of unsharpness for a projection taken with a 0.3 mm focal spot, 76 cm SOD and 4 cm OID?
0.016 mm
44. 40 ms = ____ seconds
0.04
If the peak energy of the x-ray beam is 100 kVp, a protective lead apron must be the equivalent to at least which of the following measures?
0.25-mm thickness of lead
15. A 10-bit ADC allows how many shades of gray or brightness levels to be displayed:
1024
20. A digital photospot camera typically operates as a _____ scan line system
1024
18. Typical power source for recharging batteries:
110-120 volts
10. Spatial frequency is measured in:
LP/mm
4. On a mobile radiographic unit, which of the following meters would indicate whether sufficient electricity was being supplied to the machine from a wall outlet?
LV
40. By synchronizing light waves so that all their wavelengths peak and trough together in phase, we obtain:
Laser
33. Optimizes mammography services nationwide:
MQSA (Mammography Quality Standards Act)
Defines the size of a projected image in relation to the SID and the SOD:
Magnification formula
Rad:
Patient radiation exposure in terms of radiation dose.
34. No overexposed digital image should ever be repeated, no matter the EI, unless ______ has occurred:
Saturation
26. When re-processing an image under a different procedural algorithm, it is recommended that the changed image be:
Saved as a labeled copy
58. Whenever there is an insufficient sampling rate for a high-frequency digital image, _____ artifacts may be created:
aliasing
45. In an induction motor:
both the rotor and the stator may have windings
9. In an induction motor:
both the rotor and the stator may have windings
23. Which of the following emits by far the brightest light:
an x-ray film "viewbox" illuminator
Beta particles can be emitted from:
any neutron
31. When a photostimulable phosphor plate is stimulated by a laser beam, the color of light emitted from a barium fluorohalide crystal is:
blue-violet
10. Which interaction produces only secondary photons within the patient?
coherent scattering
33. Which of the following is best used to actually measure grid effectiveness?
contrast improvement factor
14. All forms of radiation move _____ from one point in space to another
energy
16. When the distance between two masses is cut in half, the force of gravity attracting them together is changed to a value:
four times as large as before
19. Many systems present the histogram with an "S"-shaped exposure response curve overlying the histogram. The steeper the slope of this curve, the:
higher the image contrast
17. Exposure field recognition is normally done as part of:
histogram analysis
26. UNIVAC, EDVAC and ENIAC are:
historic computers
7. Patient exposure levels for fluoroscopy were excessive until the invention, in 1948, of the:
image intensifier tube
17. One main reason that the dynamic range of a digital image processing system must be much greater than the actual gray scale used in the image is to prevent data clipping when the:
image is windowed for brightness or contrast
With all other factors unchanged, if OID is increased, subject contrast in the remnant beam will:
increase as a direct result
With all other factors unchanged, if SID is reduced, image penumbra will:
increase as a direct result
The goal of the Alliance for Radiation Safety in Pediatric Imaging is to:
increase awareness of the need to reduce patient dose for pediatric patients.
46. In any transformer, the change in amperage is always ___________ the turns ratio of the transformer:
inversely proportional to
When the time spent in a higher radiation area is reduced or limited, occupational exposure:
is also reduced.
43. In the secondary coil of a transformer, induced electrical current will always flow in the opposite direction from the current supplied to the primary coil. This:
is known as Lenz's law
8. All scatter radiation:
is secondary radiation
43. When snow is forming from droplets of water in a cloud, the surrounding air:
is warmed
4. Cieszynski's law states that to minimize distortion when an object cannot be placed parallel to the image receptor plate, angle the x-ray beam:
isometrically
1. Generally, an image with many different shades of gray possesses:
low contrast
6. Gaseous contrast agents, such as air, work to produce high contrast primarily because of their:
low density
2. The published standard of practice for radiographers includes all of the following except:
majority opinion
32. In effect, what an analog-to-digital converter (ADC) does is to:
mathematically round out measurements
9. A million volts would be one:
megavolt
the symbol 14/6 C, the "14" indicates the number of:
nucleons
28. The grid frequency is the:
number of lead strips concentrated into a given distance
48. A "pixelly" digital image has been:
over-magnified
47. For a radiograph, image reversal:
presents only subjective visual changes to the image
12. Off-focus radiation is:
primary radiation
7. Extremely long gray scale in an image can lead to a loss of information because:
slightly different shades of gray cannot be distinguished from one another
12. A beam verticality check shows the central ray to be precisely vertical. The field alignment test on the same unit shows one side of the beam to be accurate, but the opposite side to be off by 1 inch (2.5 cm). Taken together, these data most likely indicate:
slippage of one shutter in the collimator
28. Operating systems, assemblers and compilers are types of:
systems software
31. Which of the following occurs when the current in a wire increases?
the magnetic field strength increases
23. Any device that can change one form of energy into another is called a(n):
transducer
1. Which of the following is not a part of an automatic exposure control circuit?
transformer
6. The Digital Imaging and Communication in Medicine standard specifies the _________ of various devices:
transmission behavior
25. During x-ray exposure of a CR phosphor, within its molecular structure what do the meta-stable F centers do?
trap excited electrons
14. A more accurate term describing what dynamic range compression really does is gray scale:
truncation
20. Which of the following would cause the worst case of grid cut-off on a radiograph:
turning a focused grid upside down
18. If an object is lifted from 10 meters to 20 meters above the ground, it will have:
twice as much potential energy
14. Which of the following is not a recommended policy for technique charts:
update the chart every 6 months
3. In an AC circuit, the actual electrons:
vibrate back and forth
17. To preserve image quality and manipulation features when images are sent to clinical sites, DICOM _______ should be included on CDs or DVDs:
viewers
1. The only prominent disadvantage of the liquid crystal display (LCD) monitor is related to its:
viewing angle
37. More expensive liquid crystal diode (LCD) monitors may have angled pixel segments in order to reduce:
viewing angle dependence
18. In the image intensifier tube, the reduction of brightness at the periphery of the output screen is referred to as:
vignetting
6. Taken together, brightness, contrast and noise make up the _____ functions of any image
visibility
18. On the radiographer's hierarchy of image qualities presented in the textbook, the physicist's concepts of contrast resolution and spatial resolution best correlate with the radiographer's concepts of ___________ and ___________, respectively.
visibility, recognizability
26. Electromotive force is measured in:
volts
19. The proportion of scatter radiation present in the remnant x-ray beam is most directly and most dramatically determined by the:
volume of tissue exposed to the primary beam
34. In the x-ray tube, an example of heat dispersion by conduction is:
warming of metal ball bearings in the shank of the anode
4. Wilhelm Roentgen's discovery of x-rays on November 8, 1895:
was truly accidental, as he was investigating something else
17. The unit of measure for electrical power is the:
watt
24. The most commonly measure anatomical structures in DXA scanning are the:
Hip and spine
31. Histogram analysis can fail to identify key landmarks when a bizarre data set results in an unexpected ________.
Histogram shape
52. When held together by a force created by a difference in electrical potential, two atoms experience?
Ionic bonding
The strongest type of bonding of atoms together to form molecules is:
Ionic bonding
In the anode of an x-ray tube, what do incoming projectile electron do to atoms in the disc:
Ionize them
4. Quantitative ultrasound:
Is economical and more convenient than DXA scanning
54. DXA scanning:
Is lower in patient dose compared to routine radiographic exams
If the intensity of the x-ray beam is inversely proportional to the square of the distance from the source, how does the intensity of the x-ray beam change when the distance from the source of radiation and a measurement point is tripled?
It decreases by a factor of 9 at the new distance.
When an alpha (α) particle is emitted from an atom of uranium, how does this change the atomic mass?
It decreases by four
30. What has been the impact of digital imaging technology upon the use of high-kVp techniques:
It has made them more relevant, and more practical to apply
28. What is the effect of increasing kVp upon sharpness of detail in the image:
It is not related to sharpness
When gamma (γ) radiation is emitted from a radioactive atom, what happens to the atom's Z number?
It remains unchanged
24. Why is a 16:1 ratio grid never used in a general procedures x-ray table?
Its selectivity demands perfect centering and perpendicularity of the beam
22. The inventor who developed a means of focusing the electron stream in the x-ray tube was:
Jackson
4. The more advanced, full-power units use ______ energy for a power supply.
Battery
18. Although both appear dark overall on conventional film, a truly fogged radiographic image differs from an overexposed image in that the fogged image:
Displays no white areas at all
5. A small magnet or compass needle will always be deflected by nearby:
Electrical currents
5. How many elements are in the molecule depicted below? LaSO4
Three
23. Because the subpixels can be treated by the computer as separately addressed elements for a monochrome (black-and-white) display monitor, we obtain _____ the spatial resolution of a color display monitor.
Three times
28. All of the following are steps listed in Fuji's Virtual Grid software EXCEPT:
Unsharp mask subtraction
As a result of beta (β) decay, an atom gains:
a proton
18. Which of the following QC tests for digital imaging can be reasonably performed visually by a radiographer: a. field uniformity b. erasure thoroughness or "ghosting" c. intrinsic (dark) noise d. uneven spatial resolution
all of the above; field uniformity, ghosting, intrinsic noise, uneven spatial resolution
20. Which of the following are parts of the CPU? a. memory b. the control unit c. the arithmetic/logic unit
all of the above; memory, the control unit, the arithmetic/logic unit
4. The production of scatter radiation is most dramatically affected by the:
amount of tissue exposed
13. Remaining within the practical range of diagnostic brightness (density) values, (that is, without going to extremes), a radiographic image's:
average brightness can be changed up or down without changing its contrast
30. Temperature measures the _____ of molecules.
average kinetic energy
27. The amount of heat storage capacity of a rotating anode depends on the anode's: b. rotational speed c. disc diameter
b. rotational speed & c. disc diameter only
38. Even with proper use and normal function, over time the entire focal track of the x-ray tube anode:
becomes roughened
14. Generally, for an image with insufficient visibility of some details, which of the following should be adjusted first:
contrast
16. Misunderstandings about radiographic technique and the nature of digital imaging, combined with the extremely broad exposure latitude of digital imaging systems, has led to what problem:
dose creep
7. To hold together the nucleus of an atom, the strong nuclear force must overwhelm the:
electrical force
22. Scatter radiation reduces subject contrast in the signal reaching the image receptor because:
it lays down a "blanket" of roughly even exposure across an area of the image receptor
8. Which of the following is also known as "object code":
machine language
29. Information missing from the signal in the remnant x-ray beam can:
never be recovered
23. While standing behind the control-booth barrier, a radiographer makes a radiographic exposure. The x-rays scattered from the patient's body should ____________________.
scatter a minimum of two times before reaching any area behind the control-booth barrier.
2. When the field is collimated to a smaller size, the overall exposure reaching the image receptor plate decreases. This is primarily due to a reduction in:
scatter radiation
3. Damage to the surface of the anode focal track can directly affect the:
sharpness of detail (spatial resolution)
10. With insufficient penetration of the x-ray beam through the anatomy, a(n) _____ image is produced:
silhouette
23. Whenever possible the configuration of activated AEC detector cells should be selected such that:
the thickest portion of the anatomy of interest lies over an energized cell
60. To minimize patient dose in the digital age, the radiographer's goal should be to produce a digital image that presents:
the threshold of barely perceptible mottle
8. A circuit is powered by a battery. The electrons flow:
through both the battery and the rest of the circuit
36. In an automatic exposure control (AEC), adjusting the "density" control on the console re-sets the:
thyratron
20. For systems using an inverted scale for their exposure index, a low original "S" number indicates:
too high original exposure
11. For an AP lumbar spine projection, an original technique of 40 mAs at 80 kVp, which produced a proper exposure, is adjusted using the 15% rule in a series of steps to 160 mAs at 58 kVp. For an average patient, which of the following would result:
underexposure at the receptor plate
4. After passing through the step-up transformer, the electrical current waveform is:
unrectified AC
Photoelectric effect:
x-ray interacts with an inner shell orbital electron, ejecting electron and absorbing the x-ray; outer shell electron rushes in to fill in the hole producing characteristic x-rays; low to moderate energy interaction
20. What is the amount of unsharpness for a projection taken with an 0.5 mm focal spot, 150 cm SOD and 15 cm OID?
0.05 mm
21. From 700 mA, 0.2 sec., and 160 cm SID, what new exposure time is needed to maintain radiographic exposure at 700 mA and 80 cm SID:
0.05 sec.
25. Diagnostic x-ray wavelengths range from:
0.10 to 0.5 A One-tenth to One-half angstrom or 25,000 to 150,000 volts
18. Two magnets separated by one centimeter exert a force of one gauss on each other. If the magnets are pulled to 3 centimeters separation distance, the force on each magnet will be: F=k(P1)(P2)/D2; F=(1)(1)(1)/32; F=1/9; F=0.11
0.11 gauss
51. Plank's constant times the speed of light is 12.4 when solving for wavelength in angstroms from energy in kilovolts. If a single x-ray within the beam has an energy of 65 kilovolts (kV), its wavelength must be:
0.19 angstroms
Studies of groups such as the atomic bomb survivors of Hiroshima have shown that damage to newborns is unlikely for doses below:
0.2 Gy.
20. What size is the smallest object that can be resolved by an x-ray imaging system with a spatial frequency of 2.5 LP/mm?
0.2 mm
If the spatial frequency of the remnant beam is 5 LP/mm, and the hardware pixels of a digital imaging receptor are 0.2 mm in size, what is the smallest object that can be resolved by this system?
0.2 mm
The genetically significant dose (GSD) for the population of the United States is about:
0.20 mSv
16. The repulsive potential difference between two electrons held five millimeters apart is 2 coulombs. If the distance were increased to fifteen millimeters, what will the potential difference be? Fo =_ (Dn)2 _ Fn (Do)2 ; 2/X = 152/52; 2/X=225/25; 225X=50; 50/225= 0.22
0.22 coulomb
19. What is the size of each pixel for a 1024 matrix using a 30 cm field of view:
0.3 mm
14. To obtain 70 mAs using the 200 mA station, use an exposure time of _____ seconds.
0.35
Protective eyeglasses with optically clear lenses should contain a minimal lead equivalent protection of:
0.35 mm.
16. To obtain 30 mAs using the 75 mA station, use an exposure time of _____ seconds.
0.4
What is the "soft" pixel size for a 205 mm FOV image displayed on a monitor screen with a 512 x 512 matrix of hardware pixels?
0.4 mm
22. An original exposure used an SOD of 80 cm and an OID of 4 cm. If the OID is increased to 6 cm, to what fraction of the original sharpness will the sharpness be reduced?
0.67 (2/3)
39. Microwaves travel through water at a speed of 2.25 X 108 meters per second. If the microwaves have a frequency of 3 X 1010 hertz, what is their wavelength in water?
0.75 X 10-2 or 7.5 X 10-3
13. To obtain 240 mAs using the 300 mA station, use an exposure time of _____ seconds
0.8
17. Radiographer A receives 5 mGy per second of scatter radiation standing 3 feet from the patient. What rate of radiation does Radiographer B receive standing 7 feet away?
0.92 mGy/sec
16. Which of the following equipment calibration checks should fall within plus or minus 5%: 1. exposure timer 2. mA linearity 3. mAs reproducibility 4. focal spot accuracy 5. x-ray beam alignment
1 & 3 only; Exposure timer and mAs reproducibility
61. Acceptable methods of minimizing motion unsharpness is/are: 1. Suspend respiration 2. Short exposure time 3. Increased mAs
1 and 2 only; Suspend respiration, Short exposure time
32. A CR phosphor plate should be erased prior to use if it has been in storage and accumulating background radiation for more than:
1 day
The annual effective dose limit for individual members of the general population not occupationally exposed is ___________ for continuous or frequent exposures from artificial sources other than medical irradiation and natural background (e.g. smoke detectors or television screens) , and ____________ for infrequent annual exposure (e.g. radioactive waste contact)
1 mSv; 5 mSv
The maximum weekly permitted equivalent dose for a controlled area must not exceed:
1 millisievert.
17. When a 1 mm focal spot is used with an SID of 100 cm and an OID of 50 cm, the amount of penumbra present in the image will be:
1 mm
9. The contrast appearing in a digital image is related to the: 1. total amount of acquired data 2. subject contrast of the anatomy 3. noise level in the image
1, 2 & 3; total amount, subject contrast, noise level
19. When routine radiographic techniques are used, which of the following are dramatic benefits of dynamic range compression (DRC) or tissue equalization? 1. Computer memory space is saved 2. Lung tissue is better demonstrated 3. Soft tissues are better demonstrated
1, 2, & 3; Computer memory space is saved, Lung tissue is better demonstrated, Soft tissues are better demonstrated
Diagnostic efficacy includes: 1. imaging procedure or practice justified by the referring physician. 2. minimal radiation exposure used. 3. optimal image(s) produced. 4. presence or absence of disease revealed.
1, 2, 3, and 4; imaging procedure or practice justified, minimal radiation exposure, optimal image, presence or absence of disease
Some local tissues sustain immediate consequences from high radiation doses. Examples of such tissues include: 1. bone marrow. 2. male and female reproductive organs. 3. skin.
1, 2, and 3; Bone marrow, Reproductive organs, Skin
Of the following, which are disadvantages of using pocket ionization chambers as personnel dosimeters? 1. Mechanical shock causes pocket chambers to discharge. 2. A permanent legal record of personnel exposure cannot be obtained with a pocket dosimeter. 3. False high readings may be obtained if the pocket dosimeter is not read each day.
1, 2, and 3; Mechanical shock, permanent legal record, false high readings.
Which of the following are considered to be benefits of an aggressive repeat analysis program? 1. Increased awareness among staff and student radiographers of the need to produce optimal quality recorded images 2. Radiographers generally become more careful in producing their images because they are aware that the images are being reviewed 3. When the repeat analysis program identifies problems or concerns, in-service education programs covering these specific topics may be designed for imaging personnel
1, 2, and 3; increased awareness, more careful, repeat problems
When technical radiographic exposures are to be selected, which of the following are some of the factors that should be considered? 1. Mass per unit volume of tissue of the area of clinical interest 2. Effective atomic numbers and electron densities of the tissue involved 3. Type and quantity of filtration used
1, 2, and 3; mass per unit, atomic number and densities, type and quality of filtration
Diagnostic imaging personnel receive the highest occupational exposure during which of the following procedures? 1. Interventional procedures 2. Routine fluoroscopic procedures 3. Routine radiographic examinations 4. Mobile radiographic procedures
1, 2, and 4; Interventional, routine, mobile
31. For increasing exposure, the step changes for the deviation index are multiplicative. For overexposure, each step increase multiplies the previous amount by:
1.259
28. At 25 lux, the maximum ambient lighting in a radiologist's reading room while images are being diagnosed should be less than ____ of the typical lighting for offices in general:
1/4
12. The decimal exposure time 0.167 second is equal to which fractional time:
1/6 sec
18. An object being radiographed measures 4 cm in width. The SID used was 100 cm and the object was located 60 cm above the image receptor plate. How big is the projected image?
10 cm
Grids are generally not required unless the anatomy measures greater than?
10 cm
15. The second set of shutters in a collimator is 18 cm from the focal spot and a SID of 45 cm is used. If the field size at image receptor plate measures 25 cm, how far were the shutters opened?
10 cm; 45/18=25/x; 45 X x=18 X 25; 45x=450
56. An exposure was made using 300 mA, 40 ms exposure, and 85 kVp. Each of the following changes will decrease the image exposure by one-half except a change to: 1/50 sec exposure. 72 kVp. 10 mAs. 150 mA
10 mAs
19. Which of the following combinations will produce a radiographic exposure equivalent to 10 mAs, 92 kVp and 180 cm SID:
10 mAs, 80 kVp, 135 cm SID
To ensure that the lifetime risk of occupationally exposed persons remains acceptable, the lifetime effective dose in mSv should not exceed:
10 times the occupationally exposed person's age in years.
15. If a beam of radiation containing 1000 x-rays is spread out over a square field that measures 10 cm long and 10 cm wide, what is the concentration of x-rays per square centimeter?
10 x-rays/cm2; 10×10=100 1000/100=10
13. Government regulations and scientific recommendations require that each mA station be linear to the two adjacent stations (the one above and the one below it) to within accuracy.
10%
According the line focus principle, which of the following anode target angles would project the smallest effective focal spot?
10+
13. How many cubic centimeters are there in 10 cubic meters?
10,000,000 cc; 100cm=1m
28. Coherent scattering by the Thompson effect is most likely to occur in the kVp range of:
10-30 kVp
42. During mobile C-arm fluoroscopy, the SOD cannot be less than ___ inches.
12
19. The maximum number of pulses of electricity that can be produced by a single-phase x-ray generator is _____ per second.
120
36. A class 1 LCD, used for diagnosis, must have _____ or fewer bad pixels across the entire area of the monitor screen:
15
51. A portable KUB normally requires 30 mAs at 70 kVp at a distance of 44", however, your patient is unconscious and cannot follow proper breathing instructions. Which of the following adjustments will result in a reduction of motion unsharpness but the same level of exposure to the imaging plate?
15 mAs @ 80 kVp
15. The typical range of anode bevel angles for general purpose diagnostic x-ray tubes is:
15-17 degrees
20. If a circuit contains 30 ohms of resistance with 60 volts applied, the current flowing will be:
2 amps
14. A lumbar fog density that extends about 1/4 of the way across the image has a lateral frequency of:
2 hertz
11. The size of the projected light field must be within plus or minus _________ of the actual size of the x-ray beam:
2% of the SID
17. For thoriated tungsten, the minimum temperature at which thermionic emission occurs is about:
2,000 degrees C (3700 F)
13. The end of an extension cylinder is 40 cm from the focal spot, and an SID of 100 cm is used. If the cylinder is 8 cm in diameter, what will be the diameter of the projected field at the image receptor plate?
20 cm; 100/x= 40/8; 100 X 8=x X 40; 800=40x
37. A bowling ball is dropped from the Leaning Tower of Pisa at a height of 21 meters. At this height its potential energy relative to the ground is 30 joules. What is the kinetic energy of the ball when it reaches a point 7 meters above the ground?
20 joules; 21/7=30/X, 21X=210, X=10, 30-10=20
17. Between all the different radiographic rooms within an imaging department, the automatic exposure controls should be linear to within plus or minus:
20%
39. Which of the following is an appropriate warm-up technique for an x-ray tube, to be repeated three times:
200 mA at 1 second and 70 kVp, at 5-second intervals
8. In order to eliminate any statistically significant magnification of the heart size during chest radiography, dedicated chest units frequently have the x-ray tube locked into a precisely centered position at ____ cm SID:
244 (96")
8. On a mobile unit, increase one "step" in mAs for every _____ increase in SID:
25 cm (10")
1. If the second set of shutters in a collimator is 40 cm from the focal spot, and the shutters are opened to 10 cm apart, what will the field size be at 100 cm SID?
25 cm; SID/SOD=Fir/Fa; 100/40=X/10; 100X10/40Xx; 1000=40x; 1000/40=25
35. After exposure, the stored image on a photostimulable phosphor plate will fade at a rate of about:
25% within 8 hours
16. As a rule of thumb, a 60-inch (152 cm) projection requires _____ more technique than a 40-inch (100 cm) projection for the same anatomy:
2X
45. If a textbook that is suspended 3 feet above your desk possesses 6 joules of potential energy relative to the desk, and is dropped, how much kinetic energy will it have when it reaches a point 1 ½ ft above the desk?
3 joules; 3/1.5=6/X, 3X=9, X=3, 6-3=3
1. Which of the following represents a realistic, yet exemplary repeat rate for a radiographic imaging department to strive for?
3-5%
4. The field size is changed from 35 X 43 cm to 20 X 24 cm. Which of the following adjustments in radiographic technique would maintain the overall exposure at the image receptor?
30-50% increase
11. Milliamperage (mA) is a rate just like kilometers-per-hour, only it describes how many electrons are traveling down a wire per second. If you used 60 mAs for an x-ray exposure, and the exposure time was 0.2 seconds, what mA station did you use?
300 mA
29. In a 5-bit analog-to-digital converter, each pixel will have how many possible values?
32
26. If the measured contrast between two anatomical structures in an image is 2, and the subject contrast between the two real structures has a relative value of 6, what is the modulation transfer function for this image?
33%
63. An x-ray image of the ankle was made at 40 inch SID, 200 mA, 50 ms, 70 kVp, 0.6 mm focal spot and minimal OID. Which of the following modifications would result in the greatest increase in magnification? 1.2 mm focal spot. 36 inch SID. 44 inch SID. 4 inch OID.
4 inch OID
13. Starting at 80 kVp, in order to obtain a significantly lighter exposure at the image receptor plate, the kVp must be reduced by at least:
4 kVp
36. A 100-watt stereo sound system draws 5 amps of AC electrical current. What is its impedance?
4 ohms
19. The general rule for adjusting radiographic technique when changing from a non-grid tabletop approach to the bucky tray is to:
4 times the mAs
25. If a textbook that is suspended 2 feet above your desk possesses 6 joules of potential energy relative to the desk, and is dropped, how much kinetic energy will it have when it reaches a point ½ foot above the desk?
4.5 joules
53. According to the graph, the 100 to 140 kVp energy switching system of a DXA unit produce two different energy peaks of approximately _____ keV.
40 and 80
33. From an original technique of 20 mAs at 74 kVp, which of the following techniques would increase subject contrast in the remnant x-ray beam while at the same time maintaining overall exposure intensity to the image receptor plate?
40 mAs at 63 kVp
35. From an original technique of 20 mAs at 74 kVp, which of the following techniques would decrease subject contrast in the remnant x-ray beam while at the same time maintaining the overall exposure intensity to the image receptor plate?
40 mAs at 63 kVp
21. Due the difference in atomic number alone, we find the ratio of x-ray absorption between bone and soft tissue to be about 8000/400. When we combine this with the fact that bone is also about twice as dense as soft tissue, the total factor by which bone absorbs x-rays better than soft tissue does is approximately:
40 times more effective
1. General radiography is ineffective in measuring bone loss since as much as _____ of bone mass must be lost to be radiographically detected.
40%
Which of the following groups of exposure factors will produce the greatest receptor exposure? 100 mA, 40 ms; 200 mA, 50 ms; 400 mA, 70 ms; 600 mA, 30 ms
400 mA, 70 ms
10. In a 12-bit analog-to-digital converter, each pixel will have how many possible values:
4096
50. The secondary coil of a transformer has 20,000 turns; the primary coil has 500 turns. If 120 volts is supplied to the primary coil, what is the turns ratio? 20,000/500
40:1
1. To allow some flexibility in centering of the anatomy over different portions of the receptor plate, most fixed DR units have _____ detector cells in the plate for automatic exposure control (AEC):
5
48. If one milliamp represents 6.3 X 1015 electrons, what is the total number of electrons used for an x-ray exposure taken at 200 mA and 0.4 seconds:
5.04 X 1017 electrons
An x-ray machine has a 30 kilowatt generator. If the maximum kilovoltage available is 60 kV, what will be the available tube current?
500 mA
11. An optimum exposure was obtained with 60 mAs at 100 cm SID. Which of the following will maintain the exposure at 150 cm SID:
500 mA at .27 sec.
19. Convenient SID for mobile radiography:
56"
14. Starting at 40 kVp, in order to double the overall exposure at the image receptor plate, change: kVp by a(n):
6 kVp increase
14. A flashlight holds two 1.5-volt batteries in series for a total EMF of 3 volts. The current flowing when the flashlight is turned on is ½ (0.5) amp. How much electrical resistance is being given by the flashlight's bulb and wires?
6 ohms
If a patient receiving x-ray therapy treatment receives a total dosage of 6,000 rads, the dosage may be recorded as _____ if the SI system is used.
600 cGy
1. At 100 cm SID, 200 mGy of radiation reaches the image receptor plate. By changing the distance to 180 cm, the new intensity of radiation at the receptor plate will be:
61.73 mGy; 200/x=1802/1002; 200 X 10,000=x X 32,400
20. Microwave ovens produce electromagnetic waves with wavelengths longer than those of visible light. If a particular microwave has a frequency of 4 X 1010 Hertz, what is its wavelength?
7.5 millimeters
Using the "base-60" method for variable kVp, what would be the calculated kVp for a body part measuring 7 cm?
74 kVp
7. An incident x-ray photon within the patient has 80 kV of energy. An L-shell electron with a binding energy of 2 kV speeds away from the atom, carrying 1 kV of kinetic energy. A Compton scattered photon from this interaction must have ____ of energy
77 kV
The outermost "shell" of an atom can never hold more than _____ electrons in it.
8
13. In the x-ray tube, a projectile electron knocks out a K-shell electron having a binding energy of 70 kV. Immediately after, an x-ray with 11 kV is emitted from this atom. The incoming projectile electron must have been carrying no less than _____ of kinetic energy.
81 keV
5. Upon angling the x-ray beam 25 degrees from vertical with an image receptor plate placed on the tabletop, what must the tube-to-tabletop distance be in order to maintain an approximate SID of 100 cm?
87.5 cm
4. Using the "base-60" method for variable kVp, what would be the calculated kVp for a body part measuring 14 cm:
88 kVp
32. Maximum electromagnetic induction will occur when a conductor (wire) moves through a magnetic field at what angle?
90 degrees
18. Starting at 70 kVp, to quadruple the overall exposure reaching the image receptor plate, the kVp should be changed to:
92
66. In surgery or in the emergency unit, which situation should be considered?
A. The stress of performing a high-tension environment, and C. The presence of additional critical equipment
1. Standardizing and simplifying technique: a. Increases consistency b. Narrows the range of potential causes of equipment failures c. Reduces the probability of errors
All of the above; Increases consistency, Narrows the range of potential causes of equipment failures, Reduces the probability of errors
18. A disadvantage of using molybdenum for the anode material in mammography tubes is: Less x-ray photon output. Increased mAs required to maintain film density. Increased patient dose. All of the above.
All of the above; Less photon output, Increase mAs, Increased dose
38. Virtual grid software allows: a. Most procedures to be done without a conventional grid at all b. Lower grid ratios to be used when a conventional grid is employed c. Much greater flexibility in positioning, centering, and angling
All of the above; Most procedures to be done without a conventional grid at all, Lower grid ratios to be used when a conventional grid is employed, Much greater flexibility in positioning, centering, and angling
33. Which of the following features at the radiologist's workstation can be part of the PAC system: a. Prefetch programs b. Computer-aided-diagnosis (CAD) programs c. Intelligent image hanging protocols
All of the above; Prefetch programs, Computer-aided-diagnosis (CAD) programs, Intelligent image hanging protocols
24. Breast compression: Provides a more uniform film density. Improves visualization. Reduces magnification. All of the above.
All of the above; Provides a more uniform film density, Improves visualization, Reduces magnification
31. Virtual grid software has been clinically demonstrated to: a. Reduce the occurrence of artifacts from grid misalignment b. Allow flexibility in angling and centering the CR for trauma procedures c. Reduce patient dose by 50-70%
All of the above; Reduce the occurrence of artifacts from grid misalignment, Allow flexibility in angling and centering the CR for trauma procedures, Reduce patient dose by 50-70%
In radiography, which of the following are mathematically quantifiable? A. repeated exposures. B. image detail. C. image contrast.
All of the above; Repeated exposures, Image detail, Image contrast
20. In the digital age, patient dose can be minimized, and positioning flexibility increased by: a. Using lower grid ratios b. Doing aerated thorax procedures non-grid c. Not using grids on knees
All of the above; Using lower grid ratios, Doing aerated thorax procedures non-grid, Not using grids on knees
Of the following radiologic procedures, which is(are) considered nonessential? A chest x-ray on scheduled admission to the hospital. Lumbar spine x-rays as part of a preemployment physical examination. Whole-body multi-slice computed tomography (CT) screening.
All of the above; chest x-ray, l-spine, whole body CT
4. The type of generators used in dedicated mammography machines allows very precise control of: kVp. mA. Time. All of the above
All of the above; kVp, mA, time
3. During mobile radiography, it is the radiographer's responsibility to protect? A. the patient B. Other health professionals C. the public D. all of the above
All of the above; patient, professionals, public
1. Mobile examinations may require: a. special adaptations of routine projections. B. imaginative equipment manipulation. C. innovative technical factor considerations. D. all of the above.
All of the above; special adaptations, imaginative manipulation, innovative tech factors
40. Because they are not subject to change, the pixel size formula is invalidated for: a. the dexels (detector elements) in a DR detector plate b. the pixels in a fixed sampling CR reader c. the hardware pixels of a display monitor
All of the above; the dexels (detector elements) in a DR detector plate, the pixels in a fixed sampling CR reader, the hardware pixels of a display monitor
24. Types of magnets include: a. natural "lodestones" b. artificial or "permanent" c. electromagnets
All of these; lodestones, artificial or permanent, electromagnets
3. In air, sound is a series of: a. compressional waves b. compressions and expansions of the air molecules c. pressure changes above and below normal d. all of these
All of these; waves, air molecules, pressure changes
In which of the following human populations is the risk for causing a radiation-induced cancer not directly measurable?
All patient in diagnostic radiology subjected to a radiation dose below 0.1 Sievert
23. DXA scanning systems?
Are classified as fan beam or pencil beam, May use a rare-earth filtered x-ray source, May employ a synchronous, high frequency generator to switch between photon energies. All of the above
26. DXA scans of the spine:
Are considered more reliable than those of the hip or forearm
28. Mammography x-ray tubes:
Are tilted to place the CR at chest wall
41. According to the diagram seen below, the highest resolution in LP/mm will be demonstrated at the ____.
Areola
Which of the following elements has a Z-number of 56?
Barium
21. Which of the following is another term for use factor (U)?
Beam direction factor
31. Digital processing and the calculation of the exposure indicator depend upon the identification of key landmarks, "troughs" or "peaks", in the ________ curve that is plotted by connecting the uppermost points of each bar in the graph of the acquired histogram:
Best-fit
8. How is the "speed" of a CR system determined?
Department management and QC technologists decide what it will be upon installation
36. Xerox:
Developed a dry process for mammography
29. Which of the following is to be prominently displayed immediately after every exposure to indicate how far off the radiographic technique was from an ideal exposure level:
Deviation index
30. A material which is slightly repelled by a magnet is classified as:
Diamagnetic
60. Which of the following would be caused by fluctuations in the electrical current passing through the image acquisition system or digital processing system:
Electronic aliasing
24. The electronic version of a patient's chart, used by a particular healthcare provider, is the:
Electronic medical record
High-pass filtering only allows _____ to pass through processing to the final displayed image.
High frequencies
The advantage to using a larger focal spot is?
Higher exposures can be used
38. During fluoroscopic image intensification, the primary bean exits the patient and strikes the _____ of the image intensifier.
Input screen
13. Where are electric charges found in a conductor?
On the external surfaces
The end product(s) of the Compton effect is (are):
One scattered photon, one ejected electron, and an orbital vacancy
17. Two charged particles held close together are released. As the particles move, their velocity increases. The two particles must have:
Opposite charge signs
18. Throughout the entire imaging sequence for a CR system, how many times is the photostimulable phosphor plate caused to glow?
Twice
59. The complete or "true" image shadow of a radiographic image is called:
Umbra
21. On DR equipment, when the grid is left in place for small extremities such as the forearm or ankle:
Unnecessary patient dose will be 3 to 4 times that of non-grid technique
Photodisintegration:
Very high energy x-ray interacts with a nucleus and ejects part of the nucleus.
While the variable kVp approach may be used for radiographic technique, it is important that mas be changed instead of kVp if:
Violating the minimum kvp rule may result in inadequate penetration
10. In the digital age, what innovative software is strongly recommended for all mobile and trauma x-ray procedures, because it allows the radiographer to work around the patient "as they lie" without worrying about grid cut-off from angling, alignment and positioning adaptations:
Virtual grid software
17. Computed radiography (CR) is a digital imaging technique that acquires image data from:
a photostimulable phosphor plate scanned by a laser beam
17. An atom is said to be in its "ground state" when:
all electrons are at their lowest energy level
1. The total subject contrast created between two tissues within the patient is dependent upon the differential absorption resulting from:
all interactions combined
15. When the kVp is increased, overall exposure at the image receptor plate increases because: a. More x-rays are emitted from the x-ray tube b. the x-ray beam has higher average energy c. the x-ray beam penetrates more through tissues
all of the above; More x-rays are emitted from the x-ray tube, the x-ray beam has higher average energy, the x-ray beam penetrates more through tissues
1. Which of the following are recommended areas for standardization within the imaging department? a. Radiographic projection routines b. Exposure factors c. Image processing parameters
all of the above; Radiographic projection routines, Exposure factors, Image processing parameters
18. Sources of ionizing radiation include: a. the environment b. medical use of radiation c. consumer products d. food
all of the above; environment, food, medical, consumer products
4. Diagnostic information can be lost if an image has: a. excessive contrast b. excessive gray scale c. excessive blur
all of the above; excessive contrast, excessive gray scale, excessive blur
21. Mottle in a CR or DR image can result from: a. insufficient kVp b. insufficient mAs c. improperly calibrated AEC
all of the above; insufficient kVp, insufficient mAs, improperly calibrated AEC
37. When exposing multiple fields on a single CR receptor plate, which of the following assists the computer in avoiding exposure field recognition errors: a. keep the anatomy centered within each field b. keep the fields parallel to each other c. keep the fields equidistant from each other
all of the above; keep the anatomy centered within each field, keep the fields parallel to each other, keep the fields equidistant from each other
6. In electrical current, electrons always move rather than protons because by comparison, electrons: a. are loosely bound in the atom b. have much less mass (are "lighter") c. are far from the nucleus
all of the above; loosely bound, less mass, far from nucleus
4. Even though the AEC is being used, it is still necessary for the radiographer to set the x-ray machine for: a. optimum mA b. optimum kVp c. detector cell configuration
all of the above; mA, kVp, detector cell config
7. The overall resolution of an image depends upon: a. sharpness b. contrast c. visibility d. geometrical integrity
all of the above; sharpness, contrast, visibility, geometrical integrity
8. Because the surface area of an object change less drastically (by the square) than the volumes of objects: a. small insects can float on water b. larger potatoes take longer to cook c. thicker x-ray tube anodes take longer to cool
all of the above; small insects can float on water, larger potatoes take longer to cook, thicker x-ray tube anodes take longer to cool
48. Which of the following are distinct advantages of the CCD for medical fluoroscopy? a. small size and flat shape b. high detective quantum efficiency (DQE) c. three times the dynamic range (gray scale)
all of the above; small size and flat shape, high DQE, three time the dynamic range
54. During mobile radiography, it is the radiographer's responsibility to request ____ to leave the immediate area prior to exposure. A. the public B. physicians C. ambulatory patients
all of the above; the public, physicians, ambulatory patients
4. Which of the following are essential considerations when using automatic exposure control with a DR or CR system? a. the use of high kVp techniques b. exact centering of the anatomy c. correct selection of activated detectors
all of the above; the use of high kVp techniques, exact centering of the anatomy, correct selection of activated detectors
56. Proper tube-grid alignment is important during ____ radiography. A. trauma B. mobile C. stationary
all of the above; trauma, mobile, stationary
51. After exposure to the imaging plate, which of the following affects the displayed image contrast for a digital image: a. windowing b. gradation processing c. detail processing d. rescaling
all of the above; windowing, gradation, detail, and rescaling processing
4. Tungsten is used in x-ray tube anodes because: a. it has a very large nucleus to slow down passing electrons and release x-rays b. it has lots of orbital electrons for projectile electrons from the filament to "run into" c. it has a very high melting point so it can withstand constant electron bombardment
all of these reasons; large nucleus, lots of orbital electrons, high melting point
6. To achieve proper alignment of the x-ray tube during mobile procedures, radiographers must position themselves: a. behind the x-ray tube to evaluate lateral alignment b. at right angles to the CR to evaluate cephalic/caudal alignment c. at the greatest feasible distance to better see alignment
all of these; behind x-ray tube, at right angles, at greatest distance
6. For most modern radiographers, the pursuit of continuing professional education is a matter of: a. continuing certification b. professionalism c. improved patient care
all of these; continuing certification, professionalism, improved patient care
2. The use of repeat analysis in a radiographic imaging department provides pertinent direction for: a. in-service topics b. management decisions c. cost-efficiency data
all of these; in-service topics, management decisions, cost-efficiency data
30. The reason to use technique charts is that: a. more consistent radiographic quality is achieved b. professionalism is enhanced c. departmental costs for repeats can be cut d. radiation exposure to patients can be cut
all of these; more consistent radiographic quality is achieved, professionalism is enhanced, departmental costs for repeats can be cut, radiation exposure to patients can be cut
20. In the x-ray tube anode, increasing the kVp increases the: a. number of bremsstrahlung interactions b. overall output (quantity) of x-rays c. average energy of x-rays produced
all of these; number of bremsstrahlung interactions, overall output (quantity) of x-rays, average energy of x-rays produced
6. With an 80-kVp x-ray beam doubling the mA would double the number of which photons in the primary x-ray beam? a. those at 20 kV b. those at 50 kV c. those at 79 kV
all of these; those at 20 kV, 50 kV, 79 kV
16. In projection geometry, which of the following portions of the x-ray beam diverges isotropically?
all primary rays except the central ray
25. The minimum kVp is defined as the lowest kVp that provides some degree of x-ray penetration through ___________ in the body part being radiographed.
all tissues of interest
30. What is a device called that measures electrical current?
ammeter
27. Which of the following is not related to the force applied to an electrical charge?
amperage
28. In a series circuit, what cannot change throughout the circuit:
amperage
23. A photomultiplier tube is incorporated into the CR reader in order to:
amplify and covert visible light into a measurable electronic signal
1. All of the following are general domains in which a digital image can be processed except:
amplitude
31. Which of the following is an example of a LAN?
an RIS using a PACS
44. The term electromagnetic induction refers to the production of:
an electric current
9. Which of the following best describes an algorithm:
an equation in computer language
1. In coherent scattering of x-rays by the Thompson interaction:
an excited electron emits a photon
6. Which of the following cannot be transmitted through a picture archival and communication system (PACS)?
analog angiography images
9. For gradation (gradient) processing, the S values from the rescaled data set are fed into a(n):
anatomical LUT
42. For any imaging system using digital processing, exposure field recognition errors or histogram analysis errors can cause the final image to have: a. excessive darkness b. excessive brightness c. excessively low contrast d. excessively high contrast
any of the above; excessive darkness, excessive brightness, excessively low contrast, excessively high contrast
2. For radiography, the brightness of a particular pixel within the image matrix of a digital image is related to the:
attenuation coefficient of the tissue
14. All of the following features are essential to a mobile radiographic unit except:
automatic exposure control with single field
15. For image intensifiers, there are two types of electrical devices that will change the level of brightness to compensate for differences in part thickness and tissue density, the automatic stabilization control and the:
automatic gain control
16. In an x-ray tube anode, if a projectile electron from the filament passes near a tungsten atom's nucleus, it will:
be slowed down by nuclear attraction, change direction, and lose energy in the form of an x-ray
19. The port of the x-ray tube in mammography is composed of?
beryllium
13. To engage the small focal spot in a dedicated mammography tube, _____ focusing must be used.
biased
18. The nuclear force which holds electrons in "orbit" around an atom is called:
binding energy
52. Generally, phosphor elements with higher atomic numbers absorb more x-rays; However, an exception to this rule can occur if lowering the atomic number better matches the __________ of the phosphor element to the typical energies in a diagnostic x-ray beam:
binding energy of the k-shell
5. A radiograph of an aluminum step wedge demonstrates only very small differences from one density (brightness) to the next. This image possesses: a. low contrast b. long gray scale
both a and b; low contrast, long gray scale
The projected bone on a radiograph is twice as wide, but three times as long as the real bone. The image is: A. Distorted B. magnified
both a. distorted & b. magnified
5. The projected image of a bone on a radiograph is twice as wide, but three times as long as the real bone. The image is: a. magnified b. distorted
both magnified & distorted
7. The ability to distinguish adjacent details as being separate and distinct depends upon: a. visibility factors b. geometrical factors
both of these; visibility factors and geometrical factors
26. When a magnification mode is selected on an image intensifier, which of the following will increase: a. patient exposure b. input phosphor size c. resolution
both patient exposure and resolution
42. An x-ray tube rating chart is unique to: a. the particular focal spot used b. the particular machine used
both; particular focal spot, particular machine
22. Which of the following would be an appropriate application for a very low mA station:
breathing technique
1. Most of the primary x-ray beam consists of:
bremsstrahlung
13. The central portion of the output screen on an image intensifier tube possesses greater:
brightness
13. Each character of the keyboard is normally encoded using 8 bits of binary information. This then constitutes the basic unit by which the capacity of a computer is measured, called a(n):
byte
15. By eliminating both peripheral and ambient lighting around any radiographic image (electronic or hard copy), its apparent _____ is enhanced:
contrast
23. As the line pairs of a resolution test template become smaller and thus closer together, the overlapping of their penumbra in a radiographic image causes a loss of _____ at the microscopic level:
contrast
25. For most CR systems, dragging the cursor vertically on the display screen can be used to adjust the displayed image:
contrast
36. The formula measured contrast with a grid / measured contrast without a grid defines the _________ for a radiographic grid:
contrast improvement factor
17. Which of the following would be best defined as the ability to display a single dot against the background density, (rather than against other dots):
contrast resolution
15. The interpretation of the user's instructions along with transfer and retrieval of the information to the proper devices for processing is the function of the:
control unit
29. For an image intensifier, the formula, candela per square meter divided by milliroentgen per ___________ second describes the.
conversion factor
13. On an automatic exposure of the abdomen in erect position, you forget to use 40" SID and leave the x-ray tube at 72" SID. The overall exposure reaching the image receptor plate will be:
correctly exposed
23. For part of a circuit that has constant resistance, as voltage is increased:
current flow is increased
5. If the mA is tripled, how must the exposure time be adjusted to maintain the original x-ray beam intensity?
cut it to 1/3
20. Using proportional anatomy, when changing from an average AP elbow projection to a PA wrist, adjust overall technique as follows:
cut to one-half
44. The essential difference between a CCD and a CMOS is the way:
data is read off the chip
45. In the digital age, displayed image brightness is:
decoupled from image acquisition
A positive charge and a positive charge held near each other are released. As they move, the force on them will:
decrease
10. With all other factors unchanged, if the field size is increased, subject contrast in the remnant beam signal will:
decrease as a direct result
With all other factors unchanged, if OID is increased, sharpness of detail in the image will:
decrease as a direct result
24. For the image of an object to be shape distorted, its length and its width must be altered by:
different degrees
27. The subtle differences in x-ray attenuation between various tissues in a body part is termed:
differential absorption
43. The CMOS outputs __________ data down wires to exit the sensor device:
digital
8. Which of the following systems requires the greatest amount of preprocessing functions?
direct digital radiography (DR)
11. If the focal spot is very much larger than the anatomy or pathology of interest, the image of the anatomy can be caused to:
disappear
4. A jukebox contains 100 or more:
discs
4. Foreshortening is a form of:
distortion (short)
21. Using proportional anatomy, when changing from an average AP ankle projection to an AP knee, adjust overall technique as follows:
double
22. Using proportional anatomy, when changing from an average AP lumbar spine projection to a true 45-degree lumbar spine, adjust overall technique as follows:
double
23. Using proportional anatomy, when changing from an AP foot projection to the lateral foot, adjust overall technique as follows:
double
29. Using proportional anatomy, when changing from an AP chest projection on a healthy 6-month old baby to the lateral chest, adjust overall technique as follows:
double
34. In the simplest terms, the thyratron of an automatic exposure control (AEC) counts up accumulating:
electrical charge
6. In a liquid crystal display (LCD) screen, in order to shut a pixel "off" so that it appears dark:
electrical current is applied to the pixel
15. The exact moment that x-rays are produced in an x-ray tube is when:
electrons are decelerated by collisions with tungsten and rhenium atoms in the anode disc
14. In the image intensifier tube, what electrical device changes the field of view (FOV) to produce a magnified image?
electrostatic lens
17. Which of the following is a possible ill effect of edge enhancement?
excessive noise
57. When a department changes a particular room from film/screen to CR, the AEC for that x-ray unit must be recalibrated according to the:
exposure indicator readings
32. Heat transfer by convection is restricted to:
fluids
12. Specific fog patterns in the latent image can be "cleaned up" by digital:
frequency processing
16. In digital image processing, high-pass and low-pass filtering are methods of:
frequency processing
10. The x-ray tube filament is made of an especially thin wire in order to increase:
friction
24. Which of the following is the correct sequence of materials traversed by the x-ray beam after it leaves the anode disc:
glass, oil, aluminum
13. Which of the following is decreased by scatter radiation:
gray scale in the remnant beam
12. For a given physical area in which an image is being displayed, the larger the number of pixels in an image matrix, the:
greater the resolution in the image
22. The Potter-Bucky diaphragm was developed to eliminate:
grid lines
18. An x-ray machine with three rectifiers would best be described as:
half-rectified
7. In a solid-state rectifying diode, when electrons try to pass through in the wrong direction:
holes in the p-type crystal drift toward the far end of the diode
16. Spatial resolution, as defined by a physicist is also called the "line spread function" or "point spread function," and correlates only to the __________ dimension of an exposure trace diagram:
horizontal
7. For a mobile AP chest radiograph to rule out fluid levels in the lungs, the patient is sitting at an angle of 20 degrees from vertical (to the mid-coronal plane). The back of the bed is 10 degrees from vertical. The x-ray beam CR should be angled:
horizontal
9. A high energy photon is partially absorbed by an orbital electron in the patient, and although the electron is ejected from its orbit, the remaining energy of the incident photon is emitted as a secondary photon. This describes which interaction:
incoherent scatter
Characteristic x-rays occur then:
incoming electron strikes an inner shell orbital electron causing it to eject from the atom, outer shell electrons fill in the suddenly vacant lower orbits; amount of energy released as x-rays is proportional to the difference in energy levels between the different orbits
1. What "across-the-board" adjustment in radiographic techniques is recommended to allow for CR operation at the 400-speed class, reduce patient exposure, and avoid image mottle?
increase all kVp levels by 15%
13. With all other factors unchanged, if SID is reduced, image penumbra will:
increase as a direct result
26. In order to double the remnant x-ray beam signal reaching the image receptor, rather than using mAs, if the kVp is increased by 15% instead, patient exposure will:
increase by 25-40%
24. Using proportional anatomy, when changing from an average AP projection for a barium enema to a 30-degree oblique projection, adjust overall technique as follows:
increase by 50%
24. In order to double the remnant x-ray beam signal reaching the image receptor, rather than using kVp, if the mAs is doubled instead, patient exposure will:
increase by double (100%)
21. The selection of a narrow window width will:
increase contrast in the image
27. An increase in the voltage applied to the photomultiplier (PM) tube in the CR reader will be associated with a(n):
increase in the system speed
Because some quantum mottle is beginning to appear on images from a particular radiographic unit, it is desired to increase the amount of exposure reaching the AEC detectors. This can be achieved by re-setting which of the following:
increase the kVp
44. The suspicions of French physicist Louis de Broglie, that electrons might sometimes act as waves, were experimentally confirmed when it was found that streams of electrons could produce:
interference patterns
19. A single CR phosphor plate is erased and then processed without exposing it to x-rays. This describes an appropriate test for:
intrinsic (dark) noise
7. To increase the proportion of photoelectric interactions (compared to Compton) occurring within the patient, one should:
introduce barium into the anatomy
10. Even though scatter radiation from the patient is random in its direction, it still follows the:
inverse square law
1. What term best describes two variables in an equation that move opposite to each other up or down, but by the same magnitude; that is, when one goes up, the other goes down by the same degree:
inversely proportional
20. For a particular amount of x-ray exposure, mA and exposure time are _____ to each other
inversely proportional
7. The concentration of x-rays is __________ proportional to the _________ of the distance:
inversely, square
53. In any detector designed to "capture" x-rays, the highest degree of x-ray absorption occurs when the k-edge of the chemical used falls:
just below the average kV of the x-ray beam
47. Which of the following has the least dramatic effect on scatter radiation:
kVp
8. At the operator console, the controlling factor of x-ray penetration in matter is?
kVp
34. Within a given procedural series, from view to view, the:
kVp should be kept fairly stable while mAs is adjusted
29. Within a given procedural series, from view to view, the:
kVp should be kept fairly stable while the mAs is adjusted
29. The appropriate electrical unit for the power rating of an x-ray generator is:
kilowatts (kW)
24. At the molecular level, sound and heat are actually both forms of:
kinetic energy
18. To analyze the histogram, the computer scans inward from both the right and left ends of the histogram looking for:
landmarks
21. In the structure of a photostimulable phosphor plate, the anti-halo layer prevents:
laser light from penetrating through to the reflective layer
When using automatic exposure control (AEC) on an adult PA chest projection, which of the following activated detector cell configurations results in the GREATEST exposure to the image receptor plate?
left and center cells only
5. The severity of the anode heel effect when using fractional focal spots in angiographic equipment imposes a limit on the:
length of receptor plates that can be practically used
24. In the remnant x-ray beam signal, even if no scatter radiation is present at all, increasing the kVp still __________ due to the increasing number of tissues penetrated.
lengthens the gray scale
10. For an LCD, the more voltage that is applied to a particular pixel, the _________ the nematic liquid crystals are:
less twisted
16. Which of the following represents the conversion of kinetic energy into potential energy:
lifting a book up off of a table
2. The anode bevel angle is used to reduce the projected focal spot size relative to the actual focal spot size, thereby improving sharpness of detail without increasing heat load on the anode disc. This is called the:
line-focus principle
4. A radiograph is actually slightly sharper at the "cathode" end than at the "anode" end. This is because of the:
line-focus principle
26. A substance which occupies a definite volume of space, but does not retain a definite shape, would be a:
liquid
8. An x-ray beam with the ability to penetrate more different types of tissue will result in what change in the quality of the signal carried by the remnant x-ray beam?
longer gray scale
32. On a mobile C-arm fluoroscopy unit, which lock would be used to re-center the image intensifier more toward the patient's head without changing the type of projection (PA):
longitudinal lock
21. Preferred radiographic grid characteristics for mobile radiography:
low ratio and high frequency
16. When maintaining proper distances may be difficult, such as in mobile radiography, you should use a(n) _____ grid.
low-ratio
11. Mammography x-ray tubes use target materials with much lower atomic numbers than tungsten. The affect this has upon the x-ray beam produced is:
lower average energy and less beam intensity
9. In a DR image receptor, smaller dexels have a:
lower fill-factor
14. Compared to workstations, display stations can typically have:
lower-resolution display screens
27. Which of the following units is best applied to a count of the number of light photons from a computer screen passing through one square centimeter at a distance of 12 inches from the screen, on their way to the human eye:
lumens
29. Compared to the cathode ray tube (CRT), the liquid crystal diode (LCD) has a very poor:
luminance ratio
30. On the SMPTE test pattern and other test patterns for electronic image display monitors, there are sets of adjacent squares with "just noticeable differences" (JNDs) in density between them. This type of pattern is designed to test:
luminance response
17. Which of the following is never a necessary item for an automatic exposure technique chart?
mAs
5. For a digital image of a particular physical size, the use of a matrix size with a smaller number of pixels will result in an image that is:
magnified
2. Which of the following controls on the control console corresponds in the x-ray machine circuit with the autotransformer?
major and minor kVp
20. Rescaling (processing) is best described as an attempt by the computer system to:
make a low-contrast raw digital image appear like a conventional radiograph prior to any post-processing
2. Which of the following approaches to radiographic technique is most recommend for mobile radiography:
manual technique using technique charts
Inverse square law:
mathematically describes the strength of an x-ray beam or its scatter as a function of distance from the source; the strength of the beam decreases with the inverse square of the distance from the source.
8. One-thousandth of a millimeter would be a(n):
micron or micrometer
27. Compared to the effects of field size and patient size, the set kVp is a relatively ___ factor in the prevalence of scatter radiation:
minor
19. On a small pediatric chest using AEC, the radiographer ensures that the detector cells are fully covered by the anatomy but leaves the field size open much wider than the anatomy. The result will be:
moderate underexposure to the AEC detectors
12. Which of the following is not a term describing coherent scattering of an x-ray?
modified scattering
6. The overall resolution for an imaging system is measured by physicists as:
modulation transfer function
16. Which of the following is not a reason why higher kVp levels reduce subject contrast in the remnant x-ray beam?
more scatter radiation is produced within the patient
1. Steeper (more vertical) anode bevel angles cause:
more severe anode heel effect
5. For distal extremity and skull procedures, a well-made technique chart for "average" patients would be usable without any modification on what percentage of all adult patients:
more than 90%
34. Hans Oersted discovered that a magnet will be deflected by a nearby electrical current. This is the principle of operation for the:
motor
14. A projection of an adult lumbar spine is taken with AEC using 60 kVp and a "density" setting of "0" or "N". The digital radiograph demonstrates significant mottle. If the projection is repeated with a new "density" setting of "+2", how will the image turn out?
mottle will still be present
12. The prominent heel affect in mammography is the result of a:
narrow target angle
15. Of the following, which is the source of most radiation the average person receives each year:
nature
17. Most radiographic images are viewed as ___________ images:
negative
22. A reference histogram that evolves by averaging it with the previous 50 procedures is called a(n) _________ histogram:
neural
40. The unit of force is the:
newton
15. In the broadest sense, anything that impedes full visibility of the details in an image may be classified as:
noise
25. The recognizability or geometrical functions in an image include all of the following except:
noise
27. When the contrast knob on the TV monitor is used to increase the contrast electronically, which of the following image characteristics also increases:
noise
32. For electronic image display monitors, test patterns consisting of circles or squares of progressing just noticeable differences (JNDs) of density from a black background mask can be used not only for testing contrast, but also for testing:
noise
9. Electronic "snow" on a display monitor or TV monitor image is a form of:
noise
27. Which of the following grid changes would result in exchanging one type of noise in the remnant x-ray beam for another type of noise?
non-grid to stationary grid
11. The advent of digital imaging has: a. rendered the use of "manual" technique obsolete b. rendered the use of "proportional anatomy" systems for technique obsolete c. rendered the "4-cm" rule obsolete
none of the above
37. Which of the following best describes memory that is saved regardless of whether the power to the computer is turned on or off:
nonvolatile
26. The exposure indicator is _________ related to the brightness of the image displayed on the monitor screen:
not
12. With all other factors unchanged, if SID is decreased, shape distortion in the image will:
not change at all
12. With all other factors unchanged, if focal spot size is increased, the overall exposure level at the image receptor plate will:
not change at all
23. With all other factors unchanged, if SID is increased, subject contrast in the remnant beam signal will:
not change at all
9. With all other factors unchanged, if the field size is increased, image sharpness of detail will:
not change at all
With all other factors unchanged, if the OID is increased, image shape distortion will:
not change at all
According to the American College of Radiology (ACR), abdominal radiologic examinations that have been requested after full consideration of the clinical status of a patient, including the possibility of pregnancy, need:
not to be postponed or selectively scheduled.
The mass number "A" of an element is equal to?
number of nucleons in the nucleus
7. In a digital image histogram graph, the vertical height of any data point along the plotted curve (measured against the y axis of the graph), indicates the:
number of pixels possessing the value
58. In the digital age, for final displayed image contrast, the kVp is best described as:
one contributing factor among many
3. An atom is said to be in an "excited state" when:
one or more electrons are in higher energy levels than usual
25. The end product(s) of the Rayleigh effect is/are:
one scattered photon only
4. For all manufacturers, the acceptable range of exposure indicator values is determined by the original x-ray exposure falling within what range of the "ideal exposure level:
one-half to double
5. Total absorption of the energy of an incident x-ray photon occurs in what portion of the atom?
only the inner shells
10. In an induction motor, an electrical current is initially induced in:
only the rotor
11. To cause an induction motor to run, an EMF is initially applied to:
only the stator
43. The photoelectric effect, described by Albert Einstein, demonstrated that because of their very high energy, x-rays usually act more like:
particles
1. The ratio of the remnant beam intensity to the primary beam intensity is the:
penetration
4. Most essential to producing a radiographic image is adequate:
penetration
7. Desirable gray scale within the remnant beam signal is lengthened by increasing:
penetration
22. Compared to conventional screen-film radiography, the greatest general advantage to all digital imaging systems is the ability to:
perform windowing and other post-processing operations on the image
1. When performing mobile radiography to demonstrate joint spaces, if you have to choose, it is most important to keep the central ray:
perpendicular to the anatomy
2. A photon with slightly more energy than the binding energy of the tissue through which it passes will most likely interact by:
photoelectric effect
3. A photon with much more energy than the binding energy of the tissue through which it passes will most likely interact by:
photoelectric effect
2. Of the following, the most likely initial interaction of diagnostic-energy x-rays in high Z-number materials such as bone and contrast agents is:
photoelectric interaction
6. What x-ray interaction within the patient produces no scatter radiation, and therefore leaves a microscopic "white spot" wherever it occurs in the resulting image:
photoelectric interaction
15. For LCD or CRT display monitors, the response time is the time required for a(n):
pixel to change brightness
33. In digital fluoroscopy, what function would be used to register a scout image and a contrast-injected image in order to carry out high detail subtraction?
pixel-shift
6. In the x-ray tube anode disc, a high-speed electron from the filament may knock out an orbital electron. The atom then fills the vacancy in this orbit by "pulling down" an electron from a higher orbit into the vacant slot. An x-ray will be emitted when this electron drops into an orbit nearer the nucleus because:
potential energy is lost by dropping in position
52. Which of the following is digital processing least capable of correcting for:
pre-fogging an entire CR plate from scatter radiation
7. Based upon surveys of recently installed CR units, which of the following was found to be so frequently extreme that department managers and radiographers are encouraged to routinely over-ride the parameters that have been pre-set by manufacturers and adjust these settings downward?
pre-set AEC back-up times
16. The ability of a PAC system to automatically search the HIS and RIS for previous images and records for patients scheduled the following day is known as:
prefetching
26. Noise in the image caused by electronic malfunctions is normally periodic, occurring at regular intervals across the image, (rather than random, such as quantum mottle). This periodic type of noise is best eliminated from a digital image using:
processing in the frequency domain
47. A great advantage of the CCD is that the CCD uses _____ to obtain ____ (frames per second), improving dynamic image quality.
progressive scanning; 60 fps
29. As the energy of projectile electrons is converted into bremsstrahlung x-ray photons in the x-ray tube anode, according to the formula for kinetic energy, by far, most of the energy imparted to the x-rays comes from the:
projectile electron's speed
31. Timers for manually setting radiographic exposure include all of the following except:
pulse timers
2.The x-ray tube envelope is composed of a heat resistant material called:
pyrex glass
28. Using proportional anatomy, when changing from an average PA chest projection to the lateral chest, adjust overall technique as follows:
quadruple
18. The temperature of the filament in the x-ray tube is directly related to the:
quantity of x-rays produced
23. Especially for digital images, insufficient mAs can be a prime contributor to _____ in the image.
quantum mottle
44. Which data processing method is best suited for displaying medical images:
real-time processing
5. Both Roentgen and Becquerel:
received Nobel prizes for physics
29. Which of the following best describes a mechanism which moves the grid back and forth in a linear movement during exposure:
reciprocating Potter-Bucky mechanism
12. What is the voltage waveform for the x-ray tube current passing from cathode to anode during an exposure:
rectified AC
22. In the CR reader, the release of trapped energy from a meta-stable F-center in a phosphor crystal is triggered by exposure to visible light in the _____ spectrum
red
26. Compared to single-phase generators, the effect of three-phase and high-frequency generators on the characteristics of the remnant x-ray beam is to slightly:
reduce subject contrast due to increased penetration
34. A reduction in the set kVp will most likely:
reduce the speed of the electron stream
49. When a single 15% step increase in kVp is accompanied by a halving of the mAs, the absorbed dose to the patient is:
reduced even more than the skin exposure (ESE)
3. If a 50-kilogram body is moved from outer space down to the earth, its mass will:
remain the same
15. When the x-ray beam intensity is increased, the ratio of penetrating x-rays to interacting x-rays:
remains equal
23. Re-mapping the brightness and gray scale of the image so that it appears like a conventional radiograph is called:
rescaling
27. Pascal's law explains how liquid pumps (such as the human heart or the brakes on your car) work: Applied pressure will be transmitted undiminished throughout any liquid because liquids:
resist compression
19. By selecting a particular mA station, one of a series of electrical __________ in the x-ray machine circuit is being engaged.
resistors
1. The ability to distinguish adjacent details as being separate and distinct is the definition of:
resolution
14. A 5-megapixel LCD screen presents much higher ________ than a 3-megapixel LCD:
resolution
22. The energy that would be released by complete annihilation of any particle of matter is referred to as that particle's:
rest energy
22. For the "black bone" processing feature, which inverts all brightness values within the image, the gradation curve is:
reversed
When using automatic exposure control (AEC) on an adult PA chest projection, which of the following activated detector cell configurations results in the LEAST exposure to the image receptor plate?
right and left cells only
8. For a passive-matrix LCD, such as might be used in a wrist-watch or calculator, the source of light is:
room lighting reflected from a mirror surface behind the LCD panel
44. CR phosphor plates are especially vulnerable to: a. overexposure b. underexposure c. scatter radiation d. background radiation
scatter and background only
7. A leaded rubber sheet placed behind the patient's back during a lateral projection of the lumbar spine prevents:
scatter radiation from being produced in the tabletop
31. Quantum mottle shows up on the fluoroscopic TV monitor as:
scintillation
11. Which of the following terms best describes the interaction of an incident x-ray photon with an atom inside the patient followed by the emission of an x-ray photon in the same direction as the original?
secondary
11. The prominent heel effect in mammography is due to a:
short SID
15. A loss of image data is reflected in the characteristic curve of the histogram:
showing a shallower slope
23. For a quality digital image, the highest possible _______ should be achieved:
signal-to-noise ratio
Studies of radiation therapy patients who received orthovoltage radiation therapy treatments provide:
significant evidence of skin damage caused by radiation exposure.
20. The CR cassette must be structured so as to protect the phosphor plate inside it from:
static electricity
22. For light emitted isotropically, in all directions from a source, one candela generates one lumen of light intensity per _____.
steradian
35. The PACS is the portion of a digital radiologic imaging system that is involved with:
storage and transfer of soft copy images
5. As field size is increased, which aspect of the remnant beam signal reaching the image receptor actually decreases:
subject contrast
10. Each line of information in the metadata begins with a DICOM _______ number:
tag ID
28. During the reading process, the intensity of light emitted by the CR plate phosphor is directly proportional to:
the amount of x-ray energy absorbed in the plate
17. For an AP foot positioned with the thickest part of the foot to the radiographer's left, which of the following could contribute to mottle in the CR or DR image?
the anode heel effect
5. For all digital imaging systems, a lower limit for exposure to the receptor is imposed by:
the appearance of quantum mottle
10. In a DR image receptor, which electronic devices directly account for the plate's ability to hold onto a latent image until it is sent into the computer?
the capacitors
If a child is placed in a CT scanner and adult protocols are used:
the child will receive a higher dose than the adult.
5. In an electrical circuit, electrons are supplied by:
the conductor (wire)
11. Positive beam limitation (PBL) should be manually over-ridden when:
the desired field size is smaller than the receptor plate size
6. Which of the following terms, all contractions, most accurately describes the individual hardware elements of a DR receptor plate that detect radiation in the remnant x-ray beam?
the dexel (or del)
7. Which of the following is recommended to make a permanent record of for each image:
the exposure indicator
13. Which part of the x-ray tube is made of thorium-impregnated tungsten:
the filament
40. Which of the following is true throughout the work day, even if procedures are not being performed, any time the power to an x-ray machine is on?
the filament is kept warm
1. Milliamperes is the unit used to measure:
the flow rate of electrons in a circuit
25. When the hardware pixels of a digital imaging system are smaller than both the object and the focal spot, what becomes the primary limiting factor for spatial resolution?
the focal spot size
18. Michael Faraday discovered that a moving magnet will induce electricity to flow in a nearby wire. This is the principle of:
the generator
21. To minimize the probability of motion during an exposure, which mA station should be used:
the highest available with the needed focal spot
29. What is the main advantage of a parallel circuit?
the independence of the branches
15. For indirect-conversion DR systems, why is amorphous silicon used rather than amorphous selenium for the semiconductor layers of the detector elements (dexels)?
the molecule must be suited to absorbing light rather than x-rays
47. Lenz's law causes the rotor shaft of the x-ray tube to spin when an electrical current is supplied to the stator (coil of wire) surrounding it because:
the north pole of the magnetic field around the rotor is repelled by the north pole of the magnetic field around the stator
25. For tungsten target material, when the kVp is increased from 60 to 80, and the mAs is unchanged:
the number of x-rays produced is increased
If an AEC exposure is used for a frog lateral hip projection when there is a large metallic hip prosthesis present, which of the following will most likely result:
the patient will be overexposed, and the digital radiograph may be light or dark
35. Which of the following is a portion of the induction motor that operates within the vacuum of the enclosed x-ray tube?
the rotor
5. The adjustment in radiographic technique to compensate for changes in the SID follows which law?
the square law
6. When using dimensional analysis to make unit conversions, a critical rule to remember is that:
the top unit must become the bottom unit in the next expression
22. Which of the following was the most important step in the development of modern electronic computers:
the transistor
5. The development of which of the following enabled DR systems to use a flat-shaped receptor plate:
thin-film transistors (TFTs)
22. For a typical LCD display monitor, each pixel consists of:
three subpixels with 6 segments each
6. After x-rays were discovered, Antoine Henri Becquerel discovered _____ which occurred naturally.
three types of radiation
24. Which of the following x-ray generators produces 720 pulses of electricity per second:
three-phase 12-pulse
20. Which of the following x-ray generators generates an average kV that is about 91% of the set kVp:
three-phase 6-pulse
21. Which of the following x-ray generators has a voltage ripple of about 14%:
three-phase 6-pulse
14. When the body part being radiographed is much smaller than the image receptor plate, the edges of the field should be collimated:
to allow ½ inch of field beyond each edge of the anatomy
20. For systems using an inverted scale for their exposure index, a high original "S" number indicates:
too low original exposure
9. Automatic exposure controls stay on longer with larger patients because they are designed to terminate the exposure only on the basis of the:
total dose detected
19. In "closed systems", such as the universe, laws of conservation demand that:
total energy must be equal before and after an event
9. The complete or "true" image shadow of a radiographic image is called its:
umbra
11. As the penumbra of an image spreads, the:
umbra shrinks
19. Using proportional anatomy, when changing from an average AP cervical spine projection to an average AP shoulder, adjust overall technique as follows:
use equal technique
26. Using proportional anatomy, when changing from an average AP abdomen projection to an average Townes projection of the skull, adjust overall technique as follows:
use equal technique
27. Using proportional anatomy, when changing from an average AP cervical spine projection to a lateral skull, adjust overall technique as follows:
use equal technique
When automatic exposure control (AEC) is not used, then to ensure uniform selection of technical x-ray exposure factors, efficient imaging departments:
use standardized technique charts for each x-ray unit.
33. On the SMPTE pattern or other test patterns for electronic display monitors, two series of narrow horizontal bars, one with high contrast alternating black and white and the other with low contrast alternating dark gray and light gray, are designed to measure:
vertical resolution
48. Studies demonstrate that in the displayed digital image, at higher kVp's, contrast is:
very slightly reduced
24. When compared to conventional screen-film radiography, digital radiography exhibits:
wider exposure latitude
21. The thin, flattened surface of the x-ray tube envelope which allows for minimum absorption of x-rays is called the:
window
4. In generic digital imaging terms, the average brightness level of the image is called:
window level
26. Because the range of the Q scale is far beyond the discernment of the human eye, this allows for _____ of the image:
windowing
15. For a large abdomen which completely covers the image receptor plate, the expected shape of the original histogram will appear:
with no spikes, only the main lobe
Compton effect:
x-ray interacts with an outer shell electron, the electron is ejected from the orbit of the atom, the x-ray is deflected from it's original path and continues with decreasing energy; moderate energy interaction
Coherent scatter:
x-ray interacts with the whole atom, the energy of the x-ray is transferred to the atom, the excess energy is given up by the atom as an x-ray traveling in an altered direction; low energy interaction.
18. Which of the following would produce the greatest exposure at the image receptor plate:
150 mA, 1 sec. 91 cm (36") SID
8. Which of the following combinations is best to obtain 20 mAs on a small child:
600 mA at 1/30 sec
15. How much over-exposure is required before a digital imaging system becomes overwhelmed with data, causing saturation to occur:
8 - 10 times
19. Upon angling the x-ray beam 35 degrees from vertical with an image receptor plate on the tabletop, what must the tube-to-tabletop distance be in order to maintain an approximate SID of 100 cm?
82.5 cm
11. Whenever a displayed image is windowed, which of the following default processes is reapplied:
Gradation processing
23. Breast compression:
Reduces magnification
31. Magnetic retentivity is a material's ability to:
Remain magnetized
On the periodic chart of the elements, when would the next atom listed move to the next group (column)?
When another proton is added
On a periodic chart of the elements, when would the next atom listed move to the next row or "period"?
When the next electron added requires a new shell
In 1898, after sustaining severe burns attributed to radiation exposure, this Boston dentist began investigating the hazards of radiation exposure and became the first known advocate of radiation protection:
William Herbert Rollins
27. The extraordinary exposure latitude of digital equipment allows the SID to be increased by 10-15%:
Without compensating radiographic technique
_______________ is the radiation output weighted time that the unit is actually delivering radiation during the week.
Workload
19. Which of the following is the best example of secondary RAM?
a compact disk
7. Analog images are best characterized as images which have:
a continuous number of gray shades
2. In the x-ray tube anode, a high-speed electron collides with an orbital electron in the K-shell of a tungsten atom. This will ultimately produce?
a high-energy characteristic x-ray
9. On an image histogram, an unusual spike to the left of the main bell-shaped lobe of the curve most likely represents:
a large metallic object
10. Which of the following will create the most electrical resistance?
a long wire with a small diameter
41. Which of the following is not an essential component of the modern x-ray tube:
a photocathode
57. Causes of grid cutoff, when using focused reciprocating grids, include which of the following? 1. Inadequate SID 2. X-ray tube off-centering with the long axis of the lead strips 3. Angling the beam in the direction of the lead strips
1 and 2; Inadequate SID, X-ray tube off-center with the long axis of the lead strips
24. The conventional fluoroscopic mA is usually about:
1 to 5
23. One megabyte is ______ bytes.
1,048,476
16. With an SID of 100 cm, and an OID of 25 cm, what is the factor of magnification?
1.33 X
1 gray equals:
100 cGy
8. Read carefully: A wave travels 6 meters each second. The air it travels through compresses and expands two times each second. What is the sound's frequency?
2 Hertz
For purposes of radiation safety, fluoroscopic output at 80 kVp is limited to no more than?
2.1 R per min per 1 mA
5. In mammography, the kVp commonly used in clinical practice varies between _____ kVp.
25 and 28
46. The binary number 011110?
30
The lead strips of a parallel grid are 2.0 mm high, and the distance between them is 0.4 mm, what is the grid ratio?
5:1
11. In computer terminology, a kilobyte is the equivalent of 1024 characters that consist of ______ bits of information.
8192
32. Osteoclasts:
Destroy bone
44. The shape of the input screen helps to control:
Distortion
49. All waves transport:
Energy
With all other factors unchanged, if SID is decreased, magnification in the image will:
Increase as a direct result
10. Which of the following elements has 82 protons in its nucleus?
Lead
42. Total removal of the breast by surgical intervention is termed_____.
Mastectomy
32. To be accurate, applying the 15% rule for kVp in order to cut the mAs in half does not cut patient exposure all the way to ½, primarily because the increase in kVp results in:
More bremsstrahlung radiation being produced in the anode/ more original x-ray intensity produced by the x-ray tube
With all other factors unchanged, if SID is decreased, shape distortion in the image will:
Not change at all
What is the chemical symbol for oxygen:
O
20. What development revolutionized the storage, management, and access of radiographic images:
PACS
14. A PACS is used as part of a(n):
RIS
If the SID is changed from 100 cm to 150 cm, and at the same time the OID is changed from 4 cm to 6 cm, the sharpness of detail in the resulting image will:
Remain the same
Small effective focal spot means the image is?
Sharper
4. An electroscope has a positive charge applied, as evidenced by the leaves of foil that are standing apart due to mutual repulsion. If electrons from the surrounding air are freed by ionization from radiation exposure:
The leaves will fall closer together
28. For tabletop procedures, radiographers should use:
The longest SID allowed by the equipment
23. Different colors of light are electromagnetic waves with different:
Wavelengths
26. A 10-cm increase in SID also increases the SSD (source-skin distance) by 10 cm. Using the square law, the mAs is then compensated for the increased SID. For the patient, entrance skin dose is still reduced because:
The mAs increase is less than would have been required to compensate for the change in SSD by the square law
The effective dose (EfD) limiting system supersedes:
The maximum permissible dose (MPD) system
6. An iron rod becomes magnetized when:
The orbital revolutions of the electrons in the atoms all align in the same direction
30. The inherent low subject contrast of breast tissue requires that we attempt to optimize:
The photoelectric effect
23. Standardization of the way health information is retrieved, exchanged, integrated and shared is achieved by:
The Health Level Seven standard
The number of mitochondria in cells varies from a few hundred to several thousand. The greatest number is found in cells exhibiting:
The greatest activity
7. After passing through the step-up transformer, the electrical current waveform is?
Unrectified AC
44. Default settings for smoothing and edge enhancement features:
can be excessive enough to cause misdiagnosis
45. Of the various imaging systems for static imaging (discussed in Chapter 31), the way that a charge-coupled device or CCD (used for dynamic imaging functions) works is most similar to the:
dexel of a direct-conversion DR receptor
5. Density trace diagrams show how both sharpness and contrast in an image affect its:
edge gradient
24. When bremsstrahlung is emitted:
it results from the conversion of kinetic energy
25. The dynamic range of the image display system is usually ____________ that of the computer image processing system:
much less than
For a particular element, all isotopes of the element have the same:
number of protons
59. A digital imaging system cannot compensate for:
too low kVp
11. A densitometer would measure the:
tonal values on a hard-copy printed image or film
15. The formula FS X OID/SOD is used to calculate the _______ in a radiographic image.
unsharpness
29. When the radiographer changes from a small to a large focal spot, she is actually:
using a larger filament
8. An example of an area operation would be:
zoom (magnification)
14. A particular joint space lies 5 cm caudally to the location of the central ray. If this joint is tilted 3.5 degrees toward the CR, how will the joint be demonstrated?
opened completely
23. Adequate penetration of all tissues without excessive production of scatter radiation would be the measure for:
optimum kVp
17. To encode is to change from:
ordinary characters to binary digits
Any image that must be performed more than once because of human or mechanical error during the production of the initial image is known as a repeat image. What effect does a repeat image have on the radiation dose received by the patient?
The patient's skin and possibly the gonads receive a double radiation dose.
57. For CR, the most common source of image artifacts is the:
phosphor plate
4. Which type of interaction is responsible for making a radiographic image possible?
photoelectric
10. When changing to a higher speed of image receptor plate, or the ratio of the grid in an x-ray table bucky is changed to a lower ratio, the thyristor of the AEC must be:
adjusted to discharge the circuit with less electrical charge build-up
30. Rescaling the image is primarily a process of __________ the acquired data set:
algebraically re-labeling
61. In digital imaging, missing lines or pixels can be caused by problems with: a. computer memory b. digitization c. communication between the image acquisition system and the computer system
all of the above; computer memory, digitization, communication
7. A line-pair group template test performed monthly on a particular x-ray unit suddenly shows a decrease in the number of line-pairs resolved. This is most likely an indication of a (n):
anode warped from heat overload
48. True saturation is a phenomenon that occurs:
at the electronic DR detector plate
10. A higher-frequency sound wave will travel through air:
at the same speed as a low-frequency sound
21. A true DICOM header is displayed as a bar:
at the top of the displayed image
2. Which organization offers a voluntary accreditation program for mammography?
ACR (American College of Radiology)
1. For the computer to process an image, modification of the analog image into digital form is accomplished be a device called a(n):
ADC (Analog-to-Digital Converter)
5. As x-ray beam energy increases:
Compton scatter increases as a proportion of all interactions occurring in the patient
5. Eighty percent of human skeletal mass is made up of:
Cortical bone
Molecules of gas:
Are not held in fixed positions relative to each other
10. Batteries used in mobile radiographic machines:
Are rechargeable
Existing data on radiation-induced genetic effects in humans:
Are still inconclusive
23. What is the main reason that characteristic interactions occurring within the patient's body do not affect the radiographic image?
Photons emitted from these interactions have too low energy
18. For digital radiography, the final degree of sharpness in the displayed image is limited not only by the focal spot size, but also by:
Pixel or dexel size
34. The Bucky factor is best used to:
convert radiographic techniques for grid changes
1. The term preprocessing is best used to describe all those computer algorithms which are designed to:
correct for flaws and limitations in the image acquisition system being used
Compared with the former material in the front of a cassette (aluminum or cardboard), the cassette front containing carbon fiber absorbs approximately ______ as much radiation, resulting in a __________ dose for the patient because ________ radiographic techniques are required to produce the recorded image.
Half, lower, lower
42. When edge enhancement is applied to an image that already possesses high contrast, an artifact may be caused in which the dark and light sides of edges are exaggerated. This artifact is called:
Halo effect
29. To cover a 24X30 cm receptor in mammography, the mammography x-ray tube:
Has an effective target angle of 22 to 24 degrees
20. Persons with severe osteoporosis:
Have a T score of -2.5 or less
28. For each image in the PACS, the exposure indicator is to be permanently stored as part of the DICOM:
Header
26. By far, the weakest link in the entire radiographic imaging chain is the:
display monitor
18. The VDT in a computer system is a(n):
display screen, keyboard and mouse
Ionizing radiation intensity decreases as:
distance from the source of radiation increases
Covalent bonding between atoms occurs because of a "defect" in the:
distribution of negative charge that forms a smooth screen around the atom
Planck's constant times the speed of light is 12.4 when solving for wavelengths in angstroms (Å) from energy in kilovolts (kVp). If the very shortest wavelength in an x-ray beam is 0.14 angstroms, what is the kVp of this x-ray beam?
88 kVp
17. The lead strips of a parallel grid are 1.6 mm high, and the distance between them is 0.2 mm. What is the grid ratio?
8:1
10. If an optimum exposure for a particular procedure was obtained with 100 mA at 100 cm SID, what new mA station would maintain the same exposure if the SID is increased to 300 cm:
900 mA
40. Recommended for dense breasts:
Rhodium
1. Which of the following does not directly affect the degree of shape distortion in an image:
SID
15. The entire distance traversed by the central ray is known as the:
SID
37. Display magnification of a digital image is controlled by all of the following except:
SID/OID ratio
4. When changing from a 100 cm (40") SID to a 75 cm (30") SID, (or half-way to one-half the original distance), if the original radiographic technique is not adjusted to maintain overall exposure, the resulting exposure at the image receptor plate will be approximately what proportion of the original?
double
8. For the average adult torso, to maintain adequate exposure at the image receptor, a full 45-degree oblique position will require what change in technique from the AP projection?
double
42. When explained as a wave, an x-ray is most accurately described as a(n):
double transverse wave
12. mA, mAs and kVp are all actually units measuring characteristics of the:
electricity that is used in the x-ray tube
17. As an electron drops down into a lower atomic shell, its positional form of potential energy is emitted as a(n) _____ form of potential energy.
electromagnetic
Bremsstrahlung:
electron passes near the nucleus of the atom, is deflected around the nucleus and loses energy in the form of x-rays and heat
50. The output phosphor of an image intensifier changes _______ energy into _______ energy.
electron; light
11. For internet access, confidentiality must be protected with __________ software:
encryption
Radiation dose:
energy imparted per unit mass of tissue; units in Rad
3. The milliampere stations are activated, heating up the filament and boiling off electrons in the x-ray tube each time you:
engage the rotor switch
11. An algorithm designed to accentuate soft tissue densities will locate the values of interest (VOI) on the histogram:
farther to the right
X-rays occur when:
fast moving electrons are suddenly decelerated by an interaction with matter; kinetic energy of the high speed electrons are converted into x-rays and heat.
35. The greater the power rating of a device, the:
faster it does work
2. In the active matrix array of a DR receptor plate, variations in alignment for multiple electronic amplifiers and differences in resistance for varying lengths of wires coming from the hundreds of detector elements cause:
gain offsets
32. The preferred type of radiation detector for automatic exposure controls (AECs) is the:
gas ion chamber
32. Which of the following is most reliable in determining the effectiveness (selectivity) of a grid?
grid ratio
10. When the backup time is reached during a breast exposure, the radiographer should select a _____ setting for the repeat radiograph.
higher kVp
13. With all other factors unchanged, if the CR is angled perpendicular to an object which is tilted in relation to the receptor plate, image shape distortion will:
increase as a direct result
19. With all other factors unchanged, if kVp is substantially decreased, subject contrast in the remnant x-ray beam will:
increase as a direct result
22. With all other factors unchanged, if SID is decreased, magnification in the image will:
increase as a direct result
20. When the field size is opened to a much larger area, the total amount of radiation striking each square inch (or square cm) of the receptor plate within the field is:
increased
23. When changing from non-grid approach to an 8:1 ratio grid, if the mAs is adjusted to maintain the overall exposure at the image receptor plate, the patient's skin dose will be:
increased by 3 times
12. All of the following increase the average energy of the x-ray beam spectrum except:
increased mAs
21. Even if scatter radiation were completely eliminated, higher kVp levels would still result in reduced subject contrast and lengthened gray scale within the remnant x-ray beam signal due to:
increased penetration
As the actual focal spot size increases, the effective focal spot size:
increases
56. Which of the following has the highest DQE, at 77%:
indirect-conversion DR plates
35. Read carefully: The lead strips of a parallel grid are 3.2 mm high, and the distance between them is 0.2 mm. What is the grid radius?
infinity
28. Even when the radiologist properly positions the fluoro tower for spot-filming, these images will have poor detail compared to regular overhead radiographs because of spot-filming's inherent:
long OID
3. Extremely low mAs could result in all of the following except:
loss of sharpness of detail
7. For mobile radiography, radiographic grids should have:
low ratio and high frequency
3. The ratio of SID to SOD is the primary control for:
magnification
7. Fractional focal spot sizes must be used for:
magnification technique
21. The purpose of a grid is to restore __________ in the remnant x-ray beam signal.
subject contrast
23. During image intensified fluoroscopy, proper collimation will reduce:
noise
25. An insufficient amount of x-ray photons at the input phosphor would increase _____ on the TV monitor screen.
noise
8. In a DR image receptor, most of the square area of each dexel is dedicated to what portion of the detector element:
the semiconductor layer
7. The resorption of bone is carried out by the action of?
Osteoclasts
8. The end of an extension cylinder is 25 cm from the focal spot, and an SID of 75 cm is used. If the projected field size at the film is 30 cm, what was the diameter of the cylinder used?
10 cm; SOD= 25; SID= 75; Fir= 30; X=Fa; 75/25=30/x; 75Xx=30X25; 75x=750; x=10
13. Approximately how many centimeters is the standard distance of the x-ray tube from the Bucky when performing tabletop radiographic procedures?
100 cm
3. During a mobile radiographic procedure, a 180 cm (6 ft) tall radiographer can use the distance from the fingertips of the outstretched arm to the opposite axilla to estimate:
100 cm (40")
To obtain 30 mAs using the 300 mA station, use an exposure time of _________:
100 ms
5. In the x-ray machine circuit, which of the following turns ratios would be most typical for the high-voltage transformer?
1000:1
30. Binary code for the decimal number 19 is:
10011
23. An object is projected using an SID of 180 cm and an SOD of 135 cm. If the projected image measures 20 cm in length, how big must the object have been?
15 cm
51. The secondary coil of a transformer has 20,000 turns; the primary coil has 500 turns, if 600 mA is fed into the primary coil, what is the resulting secondary amperage, in mA? 20,000/500=0.6/X 20,000X=300 X=0.015A
15 mA
The secondary coil of a transformer has 20,000 turns; the primary coil has 500 turns. If 120 volts is supplied to the primary coil, what will be the resulting current in the secondary coil?
15 mA
27. If the radiation dose to a patient was 8 mGy at a 180 cm distance from the x-ray tube, what would the dose be if the distance were reduced to 100 cm?
25.92 mGy
10. An original technique of 30 mAs at 80 kVp was used. Which of the following new kVp levels would be the minimum to significantly increase the exposure intensity at the image receptor plate?
84
9. An L-shell electron (with binding energy of 26 kV) is removed from an atom with an M-shell binding energy of 4 kV and an N-shell binding energy of 1 kV. If a free electron (from outside the atom) fills the vacancy of the L shell, the characteristic x-ray produced will have an energy of:
26 kV
20. From 300 mA, 1/4 sec., and 100 cm SID, what new mAs is needed to maintain radiographic exposure at 60 cm SID:
27 mAs
58. Output from battery operated units is essentially ____ pulse.
3
22. Mammography grids are: Linear. Moving. Very low ratio. All of the above.
All of the above; Linear, Moving, Very low ratio
20. Characteristic x-rays are produced in tungsten at an energy of:
69 keV
21. What is the relative sharpness for an SOD of 70 cm and an OID of 10 cm?
7
What is the atomic number for oxygen?
8
34. For a DR receptor plate, if the width of the individual detector elements could be reduced to 0.0625 mm (del pitch = 0.0625 mm), what spatial resolution could be achieved?
8 LP/mm
18. A four-meter cube contains how much more volume than a two-meter cube?
8 times more; 4(3)/2(3)=64/8=8
22. In full scientific notation, the number 0.0081 is:
8.1 X 10(-3)
18. The fractional time 1/120 second is equal to _____ ms.
8.3
8. An 80-kV photon undergoes a coherent scattering interaction with an orbital electron having a binding energy of 8 kV. What is the energy of the resulting scattered photon?
80 kV
35. What is the atomic number for lead?
82
9. If the exposure time required to produce an optimum exposure for a particular procedure is 1 second at 100 cm. SID, what exposure time would be required to produce the same exposure at 50 cm SID:
0.25 sec.
5. How efficient is an x-ray tube at producing x-rays?
0.5%
An object being radiographed measures 9 cm in width. The SID used was 100 cm and the object was located 10 cm above the image receptor plate. How wide is the projected image? IS/OS=SID/SOD
10 cm
28. High-resolution workstation screens contain how many pixels?
2,000 pixels
Compared to an electron, how massive is a proton?
2,000 times more
46. The charge-coupled devices (CCDs) used for medical fluoroscopy are about _____ in size.
2.5 cm (1")
40. Twenty percent of human skeletal mass is made up of? A. Cancellous bone B. Cortical bone C. Spongy bone
A and C; Cancellous bone and spongy bone
Which of the following is not a type of interaction between x-radiation and biologic matter?
Bremsstrahlung
8. Breast tissue is made up of? Fatty tissue, Glandular tissue, Fibrous tissue, All of the above
All of the above; Fatty, Glandular, Fibrous tissues
6. As a sound wave expands, its:
Amplitude and energy decrease by inverse proportion to the square of the distance
27. DXA scanning of the forearm:
Is preferred for suspected hyperparathyroidism. Scans the non-dominant forearm. Includes the proximal row of carpal bones. All of the above
3. Dual energy x-ray absorptiometry (DXA):
Is the current standard of care for osteoporosis detection
52. Dual energy x-ray absorptiometry (DXA):
Is the current standard of care for osteoporosis detection
8. All of the following are true of the bone remodeling process except? A. it is a balanced activity between the action of osteocytes and chondrocytes. B. it is influenced by hormones. C. osteoclast activity in excess can result in a loss of bone mass. D. osteoblast activity equals osteoclast activity in a healthy individual
It is a balanced activity between the action of osteocytes and chondrocytes
25. Modern PAC systems can store over a million medical images using 100 or more discs arranged in stacks called:
Jukeboxes
22. When a conventional stationary grid is used, and its grid lines run parallel to the scanning lines of a CR reader, which of the following is likely to result unless the grid is a high-frequency grid:
Moire artifact
For unsharp mask filtering in the special domain, the larger the size of the kernel used for averaging pixel values, the _____ the resulting mask image.
More blurry
16. Compared to other display systems, the displayed contrast for LCDs is relatively poor due to their inability to:
Produce true black
1. A digital-to analog converter (DAC) is used between which two stages of the imaging chain:
Storage and display
Which of the following curves illustrates the radiation sensitivity of a particular type of cell?
Survival curve
9. The electric force which exists between two static charges varies in direct proportion with:
The magnitude of the individual charges
24. The input phosphor of an image intensifier changes ____ energy into ___ energy.
X-ray; Light
28. For a particular radiograph, the exposure indicator shows that one half the optimum exposure was used. If this radiograph was taken using AEC, what would the density control be set to in order to correct the exposure the next time this procedure is done on a similar patient?
+2
For a particular radiograph, the exposure indicator shows that twice too much exposure was used. If this radiograph was taken using the AEC, what would the density control be set to in order to correct the exposure the next time this procedure is done on a similar patient?
-2
19. Osteopenia occurs with a T score of:
-2.0
29. All virtual grid software applies variations of which two basic digital processing operations: 1. Edge enhancement 2. Contrast enhancement 3. Noise reduction 4. Dynamic range control
2. Contrast enhancement and 3. Noise reduction only
For a half-value layer test, the following exposures are measured by an ion chamber with increasing amounts of aluminum absorber placed in the beam as indicated below: 0 mm Al: 180 mGy. 1 mm Al: 135 mGy. 2 mm Al: 90 mGy. 3 mm Al: 67.5 mGy. What is the half-value layer (HLV) for this x-ray beam?
2.0 mm Al
12. If a chest radiograph requires 4 mAs at 72", the new mAs to use at 56" would be:
2.4 mAs
34. The minimum acceptable resolution for electronically displayed images, recommended by physicist and radiological associations, is:
2.5 LP/mm
60. Which of the following sets of radiographic technique is most appropriate for the examination seen below?
2.5 mAs @ 65 kVp
24. Solve (2.6 X 103) / (9.3 X 10-4) =
2.8 X 106
16. Approximately 40% of cancers in the breast contain microcalcifications that have an atomic number of?
20
What is the atomic number for calcium?
20
When a pregnant patient must undergo a radiographic procedure, which of the following practices will minimize radiation exposure? A. Precisely collimating the radiographic beam to include only the anatomic area of interest and shielding the lower abdomen and pelvis when this area does not need to be included in the area to be irradiated C. Selecting low mAs and high kVp exposure factors for the part of the body to be radiographed
A and C; collimating, selecting low mAs and high kVp
12. The wavelength of x-rays may be best described as:
A fraction of an angstrom
54. All of the following are required to produce a laser beam except:
A piezoelectric transducer
27. Which of the following is best defined as a set of rules that facilitate the exchange of data between the nodes of any computer network:
A protocol
27. Which of the following would be unaffected by an electric charge?
A proton
22. The source of all electromagnetic waves is:
Vibrating electrical charges
59. For the following portable chest obtained in the ICU, match the medical device seen in the image to the correct symbol listed in the column to the right. A. Swan Ganz catheter. B. Endotracheal tube. C. Intraaortic balloon pump catheter. D. Mediastinal drain.
A. White straight arrow. B. Black arrow. C. Curved arrow. D. Arrowhead
33. The need for compensating filters on various projections has now been largely eliminated by: a. The inherent ability of digital processing to balance brightness across the image b. Targeted area brightness correction algorithms added to specific procedure protocols c. The power of frequency detail processing
A. The inherent ability of digital processing to balance brightness across the image and B. Targeted area brightness correction algorithms added to specific procedure protocols
27. Digital tomosynthesis in mammography: Uses a 40 degree rotation angle. Acquires ten images of the breast per sweep. Uses digital detector technology. All of the above
All of the above; 40 degree rotation angle, ten images per sweep, uses digital detector
6. Which of the following benefits result from using an increased SID: a. A larger field-of-view results for a particular image receptor b. More anatomy can be included within the view c. Patient dose is reduced
All of the above; A larger field-of-view results for a particular image receptor, More anatomy can be included within the view, Patient dose is reduced
26. One of the principal advantages of digital mammography is: The capacity to manipulate the image's contrast and density. The capacity to transmit images for consultation, teaching, etc. Archiving (PACS) for simplified storage and ready access of images. All of the above.
All of the above; Capacity to manipulate contrast, density, and transmit images, and archiving
39. Operating modern fluoroscopy units in "enhanced image mode" or "enhanced contrast mode" can result in: a. Extreme mA levels b. Excessive patient dose c. Burns to the patient's skin
All of the above; Extreme mA levels, Excessive patient dose, Burns to the patient's skin
20. Magnification projections of the breast provide: Increased resolution. A reduction in scatter radiation. Improved visibility. All of the above
All of the above; Increased resolution, A reduction in scatter, Improved visibility
Which formula is correct for calculating the magnification of a projected image?
SID/SID-OID
13. Which of the following is not a form of electromagnetic radiation:
Alpha
Which of the following humans is most radiosensitive?
An embryo or fetus during the first trimester of pregnancy
58. In coherent scattering of the x-rays by Thompson interaction:
An excited electron emits a photon
7. The disadvantage to using low kVp in mammography is its ability to produce:
An increased patient dose
If an atom has 20 neutrons, 20 protons, and 19 electrons, it is:
An ion
An isotope is an atom which has:
An unusual number of neutrons
43. Which graph of ionizing radiation output represents an anode material best suited to the radiography of soft tissue structures?
Anode B
26. Electrification is the addition to an object of:
Any charge
21. Within the patient's body, a characteristic interaction can follow:
Any ionizing event
39. For different applications, the field-of-view (FOV) can be defined by the: a. physical size of a display monitor b. physical size of an image receptor c. size of the collimated x-ray field, if smaller than the image receptor d. level of magnification (zoom) applied at a display monitor
Any of the above; physical size of a display monitor, physical size of an image receptor, size of the collimated x-ray field, if smaller than the image receptor, level of magnification (zoom) applied at a display monitor
15. As you prepare to complete a portable chest radiograph on a patient with possible congestive heart failure, you notice several tubes and lines going into the patient. Prior to making the exposure, you should:
Ask a nurse to move the lines from the image area
14. The likelihood of a bone fracture and bone integrity is best measured by:
Assessing the bone mineral density (BMD).
54. Which of the following statements about CR imaging is true:
At least 1/3 of the CR plate should be exposed
22. The principle of DXA scanning relies upon the?
Attenuation of two discrete photon energy levels through soft tissue and bone.
23. When iron is brought near a permanent magnet, the lines of the magnetic field are:
Attracted to the iron
When a vacancy exists in an inner electron shell of an atom as a result of photoelectric effect, Compton scattering, or bombardment by other electrons), the energy liberated when this vacancy is filled can sometimes be transferred to another electron of the atom and ejecting it. Electrons ejected in this way are termed:
Auger electrons
4. The electrical device in the x-ray machine circuit that permits the radiographer to adjust the kv used for an x-ray exposure is the _____?
Autotransformer
What is the chemical symbol for barium?
Ba
Which of the following formulas would be correct for calculating the magnification of a projected image?
SID/SID-OID
32. The data transfer rate through connections between various nodes of a computer network, usually measure in bits per second (bps), is controlled by the system's:
Bandwidth
12. Which of the following is the most appropriate term when describing the capabilities of a hardware device such as a display monitor:
Bit depth
The hematopoietic form of acute radiation syndrome is also called the:
Bone marrow syndrome
35. Surrounding every moving electron is: a. a magnetic field b. an electric field
Both A and B; a magnetic field and an electric field
7. The electrical force generated between charges depends on: a. how large the charges are b. how far apart the charges are.
Both of these; how large the charges are and how far apart the charges are
35. The range of acquired image data, from within the anatomy, used to analyze and rescale the digital image ranges from:
SMIN to SMAX
43. The fluoroscopic x-ray tube and image receptor are mounted on a:
C-arm
48. The formula which relates photon energy and wavelength through Plank's constant is:
E = hf
18. DXA scanning provides a statistical assessment of a person's T score and Z score. Both of these measures are similar except for the fact that the T score is:
Calculated using a normative group with peak bone mass.
11. Primary osteoporosis:
Can be classified as Type I or Type II
37. A sound wave in outer space:
Cannot travel through a vacuum
30. Which of the following is not true: In outer space, an electromagnetic wave:
Cannot travel through the vacuum of space
12. Which manufacturer refers to its exposure indicator as the exposure index?
CareStream
Which of the following will most dramatically affect the sharpness of detail?
Change OID by 10 cm
27. Which of the following can computerized processing not do to the acquired image histogram:
Change the pixel counts in each bin or file
46. Changing the field-of-view (FOV) can affect the sharpness (spatial resolution) of an image ONLY if it results in:
Changing the pixel size
38. Which of the following requires that the AEC sensitivity be re-set?
Changing to a different type of CR cassette
30. Which of the following refers to the movement of several electrons as they fall in sequence from higher energy levels to fill vacancies in lower-energy shells:
Characteristic cascade
46. Which of the following features would be generally recommended for all images being viewed:
Dark masking
5. Background exposure to a CR cassette, and small amounts of electrical current flowing through a DR detector system when no exposure is taking place, are examples of:
Dark noise
24. The ________ displayed by each subpixel in an LCD can be controlled by varying the degree of voltage (or amperage) applied:
Darkness
Image sharpness is directly proportional to which radiographic distance?
SOD
19. Radiographers must be cautious about discarding or "correcting" what appear to be low- resolution images on screening monitors prior to submitting them for diagnosis because:
Class 2 display monitors do not have the inherent resolution of radiologists' monitors
13. If the dynamic range of a digital processing system is too limited, it is possible for ________ to occur when the displayed image is later windowed:
Data clipping
31. Introduced the first dedicated mammography system:
Companie Generale de Radiographique
61. Computer software can now target specific portions of the image for brightness correction. This has reduced the need for using _______________ except in the most extreme cases.
Compensating filtration
16. What is the prevalent interaction of x-rays in soft tissue at high kVp levels?
Compton
19. The energy conservation formula EP = ES + EB + EKE is associated with which interaction:
Compton
9. Which of the following is not a reason why higher kVp levels result in reduced image contrast:
Compton interactions increase in number
What concept is defined as the difference in signal contribution (intensity) between two specific tissue areas, divided by the background noise level:
Contrast-Noise ratio (CNR)
Agfa's MUSICA digital processing suite uses the finest detail (highest frequency) image layer to derive a(n) _______________ image, which is later used to distinguish between actual noise and similar details:
Contrast-to-noise
36. For a fluoroscopic image intensifier, what does the following formula describe? Candelas/m(squared)/mR/sec=
Conversion factor
2. Charge is measured in the metric system in units of:
Coulombs
20. X-ray absorption by the photoelectric effect is proportional to the ____ of the atomic number of the tissue or contrast agent through which the x-ray beam is passing:
Cube
40. During pulsed-progressive mode DF, by selecting a 3 ms pulse width instead of a 6 ms pulse width:
Cuts patient dose in half
14. Which of the following formulas would be correct for calculating the relative sharpness of a projected image?
SOD/OID
5. The standard high-level language used to interface between all different brands of medical imaging equipment is known as:
DICOM
31. The link that transfers patient information between image acquisition stations and the RIS or HIS is a:
DICOM modality worklist
6. In teleradiology, which of the following speeds up the downloading of an image from the RIS to a radiologist's home computer?
DMA
11. Which digital technology had to wait for the miniaturization of electronic x-ray detector elements that were smaller than the resolution of the human eye?
DR
13. Which of the following modalities generally produces the sharpest images, due to large image matrix size and very small pixels:
DR and CR
41. When comparing CR and DR, which of the following best describes DR:
DR scans only the exposed area of the plate line-by-line
1. A high window level will result in which of the following on the displayed digital image?
Dark image
With all other factors unchanged, if OID is increased, overall exposure at the image receptor plate will:
Decrease as a direct result
47. At the display monitor, as the light image in magnified more and more, the matrix size for the light image itself is:
Decreasing
17. Which of the following statements is true regarding CR systems:
Digital processing is usually able to compensate for scatter caused during the exposure
17. The brightness and contrast of an electronically displayed radiographic image should NEVER be adjusted by using:
Display monitor controls
Fraternal twins may also be referred to as:
Dizygotic twins
9. Who tested over 5000 chemicals to find the best material for intensifying screens, which converted x-ray energy into fluorescent light?
Edison
20. Which of the following forces is responsible for the fact that objects seem solid even though atoms are mostly empty space?
Electrical
An electrometer is a device that measures:
Electrical charge
3. Magnetic fields are always created around:
Electrical charges in motion
39. The output screen absorbs _____ and emits _____.
Electrons; Light photons
During the pre-implantation stage of development, a radiation dose of 0.05 to 0.15 Gyt delivered to a human fertilized ovum will result in which of the following?
Embryonic death
During a radiographic examination, which of the following combinations of technical exposure factors and filtration reduce patient radiation dose?
Higher kVp, lower mAs, increased filtration
29. An object which is electrically neutral contains:
Equal number of protons and electrons
15. The law of reflection states that the angle of incidence of a light ray striking a reflective surface is:
Equal to the angle of reflection
37. Digital tomosynthesis:
Expected to become the mammography "Gold Standard"
41. In MRI, in order for radio waves transmitted into the patient's body to "knock over" protons, these waves must have their frequency "tuned" so as to resonate with _____ the of the protons:
Precession
For x-ray and gamma ray photons with energies up to 3 million electron volts (MeV), which of the following quantities may be defined as the measure of the total electrical charge of one sign, either all pluses or all minuses, per unit of mass that these two kinds of radiation generate in air only?
Exposure
Which of the following is a disadvantage of the optically stimulated dosimeter?
Exposure not determinable on the day of occurrence
45. All of the following are osteoporosis factors except: A. exposure to chronic low-level radiation B. Small stature C. Ethnicity D. Gender
Exposure to chronic low level radiation
35. Changing from fluoroscopic mode to DF (digital fluoroscopy) mode can result in a net savings in patient dose due primarily to:
Extremely short x-ray pulse times
35. Uses multiple detector elements:
Fan-beam DXA
Image sharpness is directly proportional to the _____ ratio?
SOD/OID
50. According to the test results of DXA scan seen below, the region of greatest bone mineral density is the:
Femoral shaft
14. What are materials called that are strongly attracted to a magnet?
Ferromagnetic
42. Smaller image receptor plates will result in higher sharpness only IF the system is a(n):
Fixed matrix CR system
During which of the following x-ray examinations should a radiographer always wear a thyroid shield?
Fluoroscopy and special procedures
In fluoroscopy, the amount of radiation that a patient receives is usually estimated by measuring the radiation exposure rate at tabletop and multiplying this by the:
Fluoroscopy time
25. RAM which is retained by the computer when the power supply is shut off is called:
SRAM
4. The mass of a small object, such as a pencil or pen, would be best measured using:
Grams
17. A body part that is 8 cm thicker than average requires ____ for radiographic technique.
Four times the mAs
61. For macroradiography techniques, the loss of sharpness caused by an increased OID is compensated only by the use of a _________ in combination.
Fractional focal spot
47. The energy of an x-ray photon is directly proportional to its:
Frequency
10. The normal acceptable range of exposure readings is from 100 to 400 for which brand:
Fuji
11. Which manufacturer uses the S-Number to adjust brightness in the image?
Fuji
The sun forces hydrogen nuclei together to form helium nuclei. This is called:
Fusion
21. For the gradation processing curves developed early on by Fuji, an LUT designed to lengthen gray scale and reduce contrast from the original image will generate a curve with the parameter:
GA + 1
20. For the gradation processing curves developed early on by Fuji, the shape of a particular curve which a particular algebraic formula generates is represented by the parameter:
GT (graduation type)
Which of the following instruments generally has a check source of a weak, long-lived radioisotope located on one side of its external surface to verify its constancy daily?
Geiger-Muller detector
Because occupational exposure of the radiographer can be kept as low as reasonably achievable (ALARA) through individual monitoring, the use of protective devices and other protective measures, and because exposure from radiation-related jobs will not alter the ______________________, radiation workers may receive a larger equivalent dose than members of the general population.
Genetically significant dose
SI units for radiography measurement:
Gray and Sievert.
21. On the LCD display monitors used by radiographers, we define a pixel as the smallest screen element that can represent all _________.
Gray levels in the dynamic range
23. All of the following would be classified as sources of material mottle except:
Grids
The lowest energy level possible for a particular atomic nucleus is called its:
Ground state
The vertical columns in the periodic table of the elements are called:
Groups
29. The "umbrella" computer system that integrates all information flow within a hospital or clinic is the:
HIS
20. The software standard for exchanging electronic text information between departments and institutions in a compatible format is:
HL7
33. The general formula used to determine the heat units generated by a fully-rectified single phase x-ray machine is:
HU = mA X kV X s
1. One cycle per second is the definition for the unit:
Hertz
13. Fractures of the _____ have the highest degree of morbidity and mortality.
Hip
7. In order to protect a sharply defined air-fluid level in a body cavity, the x-ray beam must be placed in the _____ position.
Horizontal
70. Which of the following technical applications is essential to demonstrate air fluid levels in portable radiography?
Horizontal x-ray beam
39. The distal forearm is the first site of choice for DXA scanning involving the diagnosis of?
Hyperparathyroidism
What is the chemical symbol for iodine?
I
15. Which of the following is not a form of Ohm's law?
I = VR
5. Which is not a form of Ohm's Law?
I=VR
12. All of the following are osteoporosis risk factors except? A. gender B. cigarette smoking C. ethnicity D. salt intake
Salt intake
11. For an active-matrix LCD, much higher brightness and continuity, and much faster response and refresh times for acquired image frames must be provided than a passive-matrix LCD can supply. To achieve this in the active-matrix LCD, each pixel has its own:
TFT
55. All of the following are correct statements about the medical applications of lasers except:
In CR readers, they are used to scan through a PSP plate to strike a PM tube
21. Electromagnetic waves would be best described as waves traveling:
In a field
Maintains exposure to the image receptor plate when SID is changed:
The inverse square law
24. Aliasing artifacts are essentially a type of:
Interference pattern
40. Which of the following directs the flow of information between the keyboard, mouse, monitor screen, printer and other I/O devices?
The BIOS
4. A compressional wave has its amplitude or "strength" measured:
In the same direction as the motion of the wave
16. In healthy adults, peak bone mass occurs:
In their twenties and mid-thirties
9. A common cause for repeat examinations in mobile radiography is due to:
Inaccurate SID measurements
19. A positive charge and a negative charge held near each other are released. As they move, the force on each particle will:
Increase
A patient enters the emergency department to be treated for severe trauma. The physician orders an AP supine chest to evaluate the lungs. What can the tech do to reduce magnification of the heart?
Increase SID as much as possible
25. If a 20-cm patient is placed in an x-ray beam with an SID of 100 cm, the SSD (source-to-skin distance) will be 100 - 20 = 80 cm. If we then increase the SID by 10 cm, the SSD will:
Increase by a greater ratio (percentage)
Which of the following adjustments in technical exposure factors decreases the production of scattered radiation?
Increase kVp and decrease mAs in compensation
The probability of occurrence of photoelectric absorption _________ as the energy of the incident photon decreases and the atomic number of the irradiated atoms _________.
Increase markedly, increase
In diagnostic imaging, the ______________ of the optically stimulated luminescence dosimeter makes it ideal for monitoring employees working in low-radiation environments and for pregnant workers.
Increased sensitivity
25. All of the following are essential components of security for medical records and information except:
Internet protocol (IP)
3. "Dead" pixels in the image caused by the failure of individual detector elements (dexels) can be filled in with data by averaging the pixel values surrounding them. This mathematical process is called:
Interpolation
36. During DF, which of the following is defined as the time required for the x-ray tube to be switched on:
Interrogation time
41. During digital fluoroscopy (DF), which of the following is defined as the slight delay required for the x-ray tube to be switched on?
Interrogation time
40. The speed of a digital imaging system is _____ to the amount of exposure required to produce adequate signal for processing:
Inversely related
50. Which of the following elements has a Z-number of 53?
Iodine
14. Electrons are in the lowest energy state when they are in the:
K shell
27. The standardized exposure indicator recommended by the AAPM in 2009 is based on actual exposure to the image detector measured in:
Kerma
13. A submatrix that is passed over the original image matrix executing a mathematical function on it is called a(n):
Kernel
CR imaging has greater ____ flexibility than conventional screen-film radiography.
Kilovoltage
42. According to the results of the DXA scan seen below, the vertebral body with the lowest bone mineral density (gm/cm2) is:
L1
44. According to the results of the DXA scan seen below, the bone mineral density comparison involved analysis of:
L1 through L4
2. When compared to CR, which of the following is not a disadvantage of DR:
Less consistency in image quality
Computed radiography, because of its higher exposure latitude, makes grid use on the pediatric population:
Less necessary than was previously believed
13. As a rule of thumb, how much of the primary x-ray beam penetrates through the patient without interacting at all with any atoms in the patient?
Less than 1%
4. Which of the following flaws is unique to the CR reader or processor, (not shared by DR)?
Light guide variations
The relationship between actual FS size, effective FS size, and anode target angle is called?
Line-focus principle
33. Rescaling operations affect each pixel throughout the image which holds a particular initial value, regardless of its:
Location in the matrix
13. The largest "structures" in the digital image, such as background densities and fog patterns, correspond to _________ layers of the image.
Low-frequency
39. Uses a 0.1 mm focal spot:
Magnification imaging
1. Presently, the only radiography examination fully regulated by the federal government is:
Mammography
38. 24-30 inches:
Mammography SID
25. What are the two differences between alpha (α) particles and beta (β) particles?
Mass and charge
15. DXA scanning:
Measures sites that are prone to fracture
22. Which of the following is defined as the effective use of medical data and information to improve the management and integration of images, efficiency, accuracy and real-time interactive functionality of imaging services:
Medical imaging informatics
Who should determine the exact shielding requirements for a particular imaging facility?
Medical physicist
30. Within each shell of an atom, which of the two rules for electron configuration always takes precedence?
Octet rule
11. How many pixels are there altogether in a 1000 X 1000 matrix?
Million/1,000,000
The barium sulfate suspension which patients drink for an Upper GI series is chemically best described as a(n):
Mixture
The smallest unit of a chemical compound is the?
Molecule
Which of the following is not a reason why higher kVp levels reduce subject contrast in the remnant beam?
More scatter radiation is produced within the patient
20. In the digital age, ________ has/have exceeded scatter radiation as the most common form of noise appearing in the final displayed image:
Mottle
56. When the AEC is used on a DR unit, off-centering of the anatomy that allows increased "raw" x-ray beam exposure to the detectors will most likely cause ________ in the final displayed image:
Mottle
5. The wave formula states that the speed of any wave can be found by:
Multiplying the number of crests that pass per second (f) by the length of each wave from crest to crest (lambda)
32. Histogram analysis failure is less common with DR systems because, unlike CR processors, the DR algorithms include in the data set for processing:
Only the exposed dexels
Which of the following agencies was previously known as the Atomic Energy Commission?
NRC
17. Classified as a "safe" profession, the average radiographer's annual occupational exposure to radiation is roughly equivalent to exposure received from:
Nature
1. The A number minus the Z number of an atom represents the number of _____ in the nucleus.
Neutrons
30. The BMD values of a DXA phantom:
Never change
_____ exists that low-level ionizing radiation causes a statistically significant increase in the threat of malignancy.
No conclusive proof
21. Superimposed tissues which are not of present diagnostic interest may be considered as a form of:
Noise
33. "Pre-fogging" a CR cassette prior to use adds to the overall amount of _______ fed into the computer, which can cause rescaling or gradation errors if it becomes overwhelming.
Noise
37. Modern digital processing includes _________algorithms that can largely compensate for fogged areas in the image:
Noise-reduction
28. Quality control procedures with DXA systems: Are done monthly. Utilize a standardized hip phantom for measurements. Are completed after each patient exam. None of the above
None of the above
25. When electrical charges move through a solid object:
Only the outer-shell electrons of atoms move
36. The sampling frequency of a CR reader, which determines the number of measurements taken across the phosphor plate, is called the:
Nyquist frequency
26. Which of the following electron transitions will result in the highest energy x-ray?
O to K; from outside the atom to K
2. The amplitude of a series of water waves is the:
One-half the vertical distance from crest to trough
3. When electrical charges move through a solid object?
Only outer-shell electrons move
35. 25-28:
Optimum kVp range
In the most accurate depiction of an atom, the electrons are held within distinct volumes of space with various shapes called:
Orbitals
7. In the absence of any current, as a series of waves moves through water, a particular molecule of water will:
Oscillate up and down, but not move horizontally
37. Bone forming cells that can go dormant when not needed:
Osteoblasts
36. T-score of -2.2:
Osteopenia
49. Fifty-eight year old male with a T-score of -2.6
Osteoporosis
9. A significant loss of bone mass and bone density results in the condition of?
Osteoporosis
In terms of occupational risk, radiography may be compared with the occupational risk associated with which of the following?
Other industries considered reasonably safe, such as government and trade
15. The lumbar spine normally has a lordotic curvature (concave posteriorly). With typical x-ray beam divergence at 100 cm SID, the best way to position the lumbar spine so as to fully open all of the intervertebral joint spaces is:
PA prone
37. The formula relating the field-of-view (FOV) to the pixel size of "soft" pixels is: For a given physical area:
PS = FOV/M
53. During mobile radiography, the radiographer must achieve maximum distance from the:
Patient
39. By leveraging the advantages of digital processing to reduce grid use, __________ can be lowered significantly:
Patient Dose
By taking advantage of digital processing to reduce grid use _____ can be lowered significantly.
Patient dose
Which of the following is frequently a problem in diagnostic pediatric radiography?
Patient motion
What is the chemical symbol for lead?
Pb
38. Lowest dose type of DXA technology:
Pencil-beam DXA
11. Materials that are easy to magnetize and to demagnetize are said to have high:
Permeability
29. The radiation dose during DXA studies:
Permits easy compliance with ALARA principles
63. In Illustration B, the relationship of the central ray to the plane of the imaging plate is:
Perpendicular
46. In the wave model of an x-ray, two transverse waves are positioned:
Perpendicular to each other
17. DXA scanning relies on the assessment of BMD for an individual and compares this value to:
Persons with peak bone mass in their twenties
31. The formula EP=EB+EKE is associated with which interaction?
Photoelectric effect
9. The two interactions in the x-ray tube resulting in x-radiation are _____, producing a wide spectrum of photon energies and _____, producing a narrow, or discrete range of x-ray energies.
Photoelectric; Characteristic
20. First to develop a portable unit:
Picker Corporation
7. Most of the thickness of an LCD monitor is due to the:
Plastic filters used to disperse the light evenly
20. The earth's magnetic field is most concentrated and strongest at the:
Poles
When using AEC, the radiographer must use much greater care in?
Positioning
10. An electrically neutral bar of metal sits on an insulated tabletop. A negatively charged object is brought near to the end of it, and at the same time a person standing on the floor momentarily touches the opposite end of the bar. The charged object is then removed from the area. The resulting charge on the metal bar is:
Positive
After the 1986 nuclear power station accident in Chernobyl, Ukraine, an attempt was made to prevent thyroid cancer in children in Poland and some other countries as a consequence of accidental overdose to iodine-131. _______________ was administered as a substitute for the take-up of 131 I
Potassium iodide
26. The Health Insurance Portability and Accountability Act (HIPAA) holds all healthcare providers accountable to maintain each patient's _______.
Privacy
17. The advantage of using molybdenum for the anode material in mammography tubes is:
Production of specific x-ray energies
15. When the distance between two charged objects is cut in half, the electrical force between them is:
Quadrupled
5. _______ is the process of testing and calibrating x-ray equipment to meet a range of acceptable performance standards.
Quality control
24. All of the following would be classified as sources of electronic noise except:
Quantum mottle
25. Which type of noise becomes visible in the image when there is an insufficient amount of signal reaching the image receptor?
Quantum mottle
33. Which of the following is designed to ensure that computerized files of images and patient information cannot be permanently lost:
RAID
Rem:
Rad that takes into account the biological effect of the radiation/Rad times a weighting factor.
34. In magnetic resonance imaging, the image is produced by detecting _____________ emitted from the patient's body:
Radio signals
21. Which of the following has its wavelength most appropriately measured in kilometers?
Radio waves
27. On a conventional radiographic image, structures that appear lighter or "white" represent tissues within the patient's body:
Radiopaque (light/white)
32. For a radiograph of a normal knee without any metal devices implanted, the acquired digital histogram will have two lobes. The second, narrower, "tail lobe" at the right represents ______ in the image:
Raw" background x-ray exposure
20. Which interaction refers to the momentary absorption of an x-ray photon's energy by the entire cloud of electrons in an atom, collectively?
Rayleigh
An inverse Fourier transform is used to:
Re-assemble the different wavelengths in an image
9. What is the component of the x-ray machine circuit outline in red below?
Rectifier Bridge; item just prior to x-ray tube
3. The CareStream™ CR system uses a logarithmic scale for its exposure indicator, with an ideal index number of 2000. If a radiograph is produced with an exposure index of 2300, what change in radiographic technique would bring it back to the ideal amount?
Reduce to one-half
21. The use of a grid in mammography: Improves radiographic quality. Increases patient exposure. Reduces scatter reaching the film. All of the above
Reduces scatter
12. An echo is the:
Reflection of sound from a smooth interface
13. Light that changes direction when passing from air through an interface into water is:
Refracted
38. Which of the following is not a process related to the interaction of x-rays within the body of a patient?
Refraction
41. A particular DR detector has dexels measuring 100 microns in width. During exposure, if the x-ray field is collimated to a size smaller than the DR detector plate, the inherent sharpness (spatial resolution) for the DR detector will:
Remain the same
18. A sub-network connecting several storage devices at remote geographic locations or other clinical sites is called a(n):
SAN
27. The probability of mottle and patient dose can BOTH be achieved by:
Removing a conventional grid and only partially reducing the mAs
11. When a particular object or molecule has a natural frequency that matches or is a multiple of the frequency of a sound wave or electromagnetic wave striking it, it will absorb the wave's energy. This principle is called:
Resonance
38. When windowing the displayed image, extreme reduction of contrast may _______ the image:
Reverse
38. To help the radiologist or cardiologist steer a guidewire and/or catheter through blood vessels, a subtracted image from a frame with maximum contrast agent opacification can be overlaid on the most recent frames taken. This technique is called:
Roadmapping
English units for radiography measurement:
Roentgen, Rad, Rem
8. Filtration and the first x-ray beam collimation devices were both first attributed to:
Rollins
25. Incoming pixel values can be made to fit a pre-set range by adjusting the degree by which they are:
Rounded
24. The bins of data from an acquired image to be used for rescaling are labeled as ___ values:
S
36. When an alternate algorithm has been used to successfully improve an image, the best follow-up for PACS storage is to:
Save both the original and the copy as separate files
24. When approving CR images, why should the radiographer generally not save adjustments made to the brightness and contrast of a "sub-optimal" original image into the PACS?
Saving the changes into the PACS permanently erases some image data
18. Which of the following statements is false:
Scatter radiation in the original remnant x-ray beam always results in a dark image after digital processing
A spot film device protective curtain, or sliding panel, of a minimum thickness of 0.25-mm lead equivalent should normally be positioned between the fluoroscopist and the patient to intercept which of the following types of radiation?
Scattered radiation above the tabletop
47. Compares patient BMD to average BMD of young adult population at peak bone density:
T-score
Which of the following types of gonadal shielding provides the best protection for a male patient when AP, oblique, and lateral projections are obtained?
Shaped contact shield containing 1 mm of lead
When a radiologic technologist declares her pregnancy to her employer, which of the following is appropriate?
She continues to perform her duties without interruption of employment, provided that she has received radiation safety counseling and follows established radiation safety practices.
23. Which of the following grids has its grid lines running crosswise rather than lengthwise:
Short-dimension (SD) grid
31. When considering electromagnetic waves, the higher the frequency (f), the:
Shorter the wavelength
13. The amount of penumbra that will be produced in a radiographic projection can be predicted using penumbra diagrams, and is based mathematically upon:
Similar triangle geometry
3. Dedicated mammography machines use _____ generators.
Single-phase, high frequency
How many atoms are in the molecule depicted below? LaSO4
Six
46. Increased osteoporosis risk factor:
Small body frame
45. In the "corpuscular" model of x-rays, they are imagined to be:
Small bundles or blobs of energy with an associated wavelength
6. At the operator console, switching from the _____ to the _____ will increase the size of the penumbra in the projected image.
Small focal spot; large focal spot
33. Osteoporosis risk factor:
Small stature
43. For GE's look feature, a "hard", "normal", or "soft" look can be applied to the image. The soft look actually applies a _______ algorithm:
Smoothing
Which part(s) of a diagnostic x-ray unit should a radiographer avoid touching while a radiographic exposure is in progress?
Tube housing, collimator, and high-tension cables
8. The north pole of a compass needle points to the earth's:
South magnetic pole
1. In physics, which of the following is not a fundamental standard of measurement?
Speed
2. In the wave formula for electromagnetic energy seen below, what constant does the letter "C" represent? C=lamda times velocity
Speed of light
45. Magnification of the displayed light image using monitor controls can be accomplished only by:
Spreading out a single pixel value across several hardware monitor pixels
20. Although computer experts define a pixel as a dimensionless point, for a typical LCD display monitors we must define a pixel as a small:
Square or rectangle with dimensions
8. Which of the following electrical devices provides the increase in current necessary to create thermionic emission at the cathode filament?
Step-down transformer
6. All of the following are related except one. Select the choice that is not related to the others. vertebral bodies, distal radius, greater trochanter, tarsals
Tarsals
Defines the effect on imaging plate exposure when kilovoltage is changed:
The 15% rule
41. The "on" and "off" states representing binary ones and zeros for a flash memory drive are based on:
The degree of resistance to electrical current
11. Which unit is equivalent to one 10-billionth of a meter?
The angstrom
61. Before entering a surgical suite, who must be consulted?
The attending physician
24. The kVp major and kVp minor controls at the console actually set which electronic device in the x-ray machine circuit?
The autotransformer
6. With current, state-of-the-art portable units:
The batteries provide power for exposures and travel
27. When radiographing the lungs or small body parts, which of the following best describes the effect of using high kVp techniques on scatter radiation:
They increase scatter, but not substantially
4. In which of the following instances will the resistance in a copper wire be decreased?
The diameter of the wire is increased.
If the number of protons within an atom's nucleus is changed, which of the following must absolutely change:
The element's name
The "principle quantum number" of an atom is related to:
The horizontal row it occupies on the periodic chart of elements
25. Proper patient positioning for DXA scans of the hip includes:
The femoral greater trochanter in profile
28. For a solid object, electric charge concentrates at:
The greatest curvature of the surface
12. Electrical charge can be neutralized if it is conducted to:
The ground
21. A histogram analysis algorithm that begins storing pixel values only when a certain minimum number of pixels holding these values is present is a(n) __________ algorithm:
Threshold
26. The absorption rate of an x-ray beam through a particular thickness of soft tissues is:
exponential
26. The use of positive contrast agents greatly improves subject contrast by:
bringing binding energies up closer to x-ray energies
At increased OID, which of the following does not spread out more than it otherwise would have?
The primary beam
The SID/SOD ratio is related to magnification in the image:
by direct proportion
The SOD/OID ratio is related to the sharpness of detail image:
by direct proportion
44. For a display monitor, which of the following is constant or fixed:
The size of the hardware pixels
Defines the intensity of radiation exposure at a given distance from the source:
The square law
8. Useful characteristic x-rays are produced in the tungsten anode:
by ionization of a K-shell electron
53. An ultrasound machine determines the location of a particular body structure by:
The time it takes for the reflected sound wave to return
3. The effect of kVp on the intensity of the remnant x-ray beam is:
exponential
3. For digital radiography, the textbook generally recommends the variable kVp approach for techniques, but it is important that mAs be changed instead of kVp if:
Violating the minimum kVp rule may result in inadequate penetration
68. Mobile examinations are difficult to accomplish because.
There are so many additional variables.
38. Experimentation with CR shows that an unprocessed, latent image will have completely faded from the plate after:
There is no practical time that can be stated
________________________ are the sensing devices most often used to measure skin dose directly.
Thermoluminescent dosimeters
42. Compared to a CCD, a CMOS:
has less sensitive surface area
36. X-rays have higher-energy photons than visible light because:
They have higher frequency than light
21. A modern DXA scanning system consists of?
Workstation, X-ray tube, X-ray detector, QC phantom, Positioning aides
10. Type II osteoporosis is distinguished from Type I in that?
Type II is age related
9. Sounds inaudible to humans, above 20,000 hertz frequency are called:
Ultrasonic
29. Which of the following is not part of the electromagnetic spectrum:
Ultrasound waves
What is the term for the proportional amount of time during which the x-ray beam is energized or directed toward a particular barrier?
Use factor
31. SPA:
Uses radioactive iodine as a photon source
53. The increased exposure latitude afforded by digital imaging includes all of the following options except:
Using low kVp levels
34. After histogram analysis and rescaling are completed, the computer "knows" where to insert these modified values in the image because prior to these operations, a log was kept recording each:
Value's location in the spatial matrix
10. Which of the following is true for the chest and for mid-sized and small extremities:
Very little scatter radiation is produced, even at high kVps
11. In order for electrical current to flow, there must be:
a closed conducting path and a potential difference
45. Which of the following must be changed in an atom in order to change the identity of the element?
Z number
1. Which of the following must be changed in an atom in order to change the identity of the element?
Z number/number of protons
48. Compares patient BMD to average BMD of similar-aged adult population:
Z-score
4. When an x-ray technique calls for 74 kVp and 80 mAs, which of the following bremsstrahlung x-rays will appear? a. 6 kVp b. 74 kVp c. 80 kVp
a & b only; 6 kVp, 74 kVp
10. Graphs must use _ ____ ___ ____ in order to accurately represent data.
a best fit line
25. Which of the following affects focal spot size? a. anode angle c. filament size
a. anode angle & c. filament size only
19. Tungsten is the principle material used in the: a. target of the rotating anode c. x-ray tube filament
a. target of the rotating anode & c. x-ray tube filament only
13. In a common circuit, electrons actually move at speeds of:
about 2.5 cm per hour/ an inch per hour
35. The dewars in an MRI machine keep the temperature of its super-conducting magnetic coils at 4 degrees above:
absolute zero
54. When compared to direct-conversion DR systems, a major reason that indirect-conversion DR systems can save patient dose is that they have higher:
absorption efficiency
13. Graduating partial absorption of the x-ray beam as a function of the varying thickness of an anatomical structure (independent of the focal spot) is referred to as:
absorption penumbra
9. As the distance from the x-ray tube to the image receptor plate changes, the intensity of radiation changes:
according to the inverse square of the distance
4. To multiply numbers with exponents:
add the exponents
6. Which of the following artifacts is related to the Nyquist frequency?
aliasing artifact
12. Which of the following are benefits of the post-processing capability of digital imaging systems in general: a. reduced patient exposure b. cost savings for imaging departments c. time efficiency for technologists and physicians d. the ability to improve image quality without repeating an exposure
all of these; reduced patient exposure, cost savings for imaging departments, time efficiency for technologists and physicians, the ability to improve image quality without repeating an exposure
11. Within the signal of the remnant radiation beam, scattered radiation can destroy: a. subject contrast b. gray scale c. visibility
all of these; subject contrast, gray scale, visibility
50. Which of the following increase the absorption efficiency of a CR phosphor plate: a. thicker phosphor layer b. phosphor compounds with high atomic numbers c. compounds that take advantage of the k-edge effect
all of these; thicker phosphor layer, phosphor compounds with high atomic numbers, compounds that take advantage of the k-edge effect
16. Any device which operates on the principle of electromagnetic induction must be powered by:
alternating current
6. When using automatic exposure control, which of the following should be approximately doubled from the expected exposure?
back-up time
24. The speed at which information can be transferred from one computer device to another is the:
baud rate
2. In physics, which of the following is a fundamental unit, (not a derived unit):
centimeters
30. "Selecting the grid ratio" in a virtual grid program actually:
changes the intensity with which the algorithms are applied
22. Which interaction is the only interaction that takes place both in the x-ray tube and within the patient's body?
characteristic
49. In a charge-coupled device (CCD), when an x-ray strikes a crystal of silicon:
charge "holes" drift to an electrode
12. In an individual DR detector element (dexel), the electronic charge built up on the capacitor is positive charge because it is generated by ______ drifting downward through the semiconductor layers to the capacitor:
charge holes
Electrostatic lenses are actually:
charged electrodes
1. In the basic x-ray machine circuit, a device which is designed to protect the entire unit from electrical overloads or short circuits is the:
circuit breaker
26. After a photostimulable phosphor plate has been scanned in the CR reader, it is then exposed to high-intensity white light in order to:
clear any of the remaining latent image from the phosphor layer
3. Which of the following devices is most recommended for both protecting the patient and improving subject contrast in the remnant beam as it reaches the image receptor:
collimator
For C-arm devices with similar fields of view, the dose rate to personnel located within a meter of the patient is:
comparable to that of routine fluoroscopy.
34. The DICOM standard was developed to ensure:
compatibility between medical systems that store information
14. Which of the following is directly proportional to the number of interactions taking place within a particular tissue in the patient?
density of the tissue
25. The wave functions of details within an image most closely resemble:
density trace diagrams
9. While positioning for an x-ray exposure, the most common purpose of angling the x-ray beam is to:
desuperimpose images
55. When the signal-to-noise ratio of the output image from a receptor is divided by the signal-to-noise ratio of the signal coming into the receptor, (with both numbers squared), we obtain the overall __________ for the system:
detective quantum efficiency
20. For medical diagnosis, it is critical for every electronic image monitor within a _____________ to be set at precisely the same luminance and contrast:
diagnostic workstation
18. From a selected mid-point in the various gray levels of a digital image, lighter areas in the image are progressively darkened, while darker areas are progressively lightened. This describes?
dynamic range compression
38. Flash memory sticks store data in the form of:
electric charges
11. A photocathode is an electrical device which emits _____.
electrons
2. Anything which converts mechanical energy into electrical energy is a(n):
generator
18. Positioning of the patient and patient motion, are both most accurately categorized as _____ variables.
geometrical
16. Due to their different points of origin within the focal spot, the gradient partial absorption of x-rays as a function of the total absorption which an anatomical structure is capable of defines:
geometrical penumbra
14. For both direct-conversion and indirect-conversion DR image receptors, the elements of the active matrix array, (semiconductor layers, TFTs capacitors and lines), are supported on a substrate made of:
glass
9. Key items of interest to caregivers are made easily accessible at the touch of a button while the image is displayed, as a DICOM:
header
22. In electrical circuits, one by-product of high resistance is:
heat
23. In the rotating anode, the use of molybdenum for the anode stem material helps prevent:
heat damage to the ball bearings
30. Which of the following types of lasers is most commonly used in CR processors?
helium-neon
3. An example of an intermediate computer language used by compilers and interpreters, not by users, would be:
hexadecimal or ASCII code
8. For the purpose of inducing thermionic emission, the current supplied to the x-ray tube filament is:
high amperage, low voltage
2. Generally, an image with only a few shades of gray possesses:
high contrast
Pair production:
high energy x-rays interact with the nucleus, x-ray is converted into an 511 keV electron and positron, positron quickly interacts with an electron and annihilates producing annihilation radiation
17. X-ray beam quality with current day portable units:
high frequency output
8. In the remnant beam signal, which of the following can reduce both subject contrast and gray scale at the same time?
high levels of scatter
1. Which of the following is equivalent to low sharpness:
high penumbra
12. An image with a steep edge gradient, and therefore a high contrast/penumbra ratio, will present:
high resolution
3. Which of the following is equivalent to low penumbra:
high sharpness
19. For any image in general, all of the following are essential for visibility except:
high sharpness (resolution)
2. To demonstrate soft tissue structures on a digital image, which of the following windowing combinations is best:
high window width, low window level
27. An x-ray generator producing electrical current at 500 hertz would be classified as:
high-frequency generator
30. Which of the following x-ray generators is most recommended for use on pediatric patients?
high-frequency generator
33. Only exposures with a deviation index of ______ should be assumed to be repeatable:
less than -3
Because most medical procedures result in fetal exposures:
less than 0.01 Gy, the risk of abnormality is small.
12. Lossless compression ratios used for medical diagnosis are defined as ratios:
less than 8:1
12. Scatter radiation affects:
occupational exposure
8. Larger focal spot sizes result in:
smaller umbral "shadows"
7. To a computer expert, a true pixel is a numerical value assigned to a(n):
point with no dimensions
18. Compared to digital imaging systems, the main disadvantage of conventional film-screen radiography was its:
poor detectability of low subject-contrast structures
5. In digital medical imaging departments with a quality control (QC) program in place, the great majority of repeated exposures is due to improper:
positioning only
6. Electricity can flow through a solid-state diode when a(n) ___________ is formed at the n-p junction:
potential bridge
16. The difference in charge between the cathode and anode during an x-ray exposure is called a(n):
potential difference
31. At the moment a liquid changes state into a gas, it changes:
potential energy
32. Because of its resistance to vaporizing at high temperatures in a vacuum, which of the following is used as lubricating material around the ball bearings in the anode stem:
powdered silver
36. The only kind of heat transfer that can take place through vacuum space is:
radiation
12. The most important reason to use technique charts is that:
radiation exposure to patients can be cut
During mammography, axillary projections should be done only on request of the:
radiologist.
14. Images are usually erased from storage after 5 days for:
radiologists' workstations
2. In a computer, information that is frequently added, deleted or changed by the computer is most likely to be stored in:
random access memory
2. The milliamperage is an actual unit for measuring the:
rate of electrical current flowing during an exposure
16. Partitioned pattern recognition software is used for:
segmentation
36. For CR, substantial fog density between two projections on the same plate can cause:
segmentation failure
55. For CR, when multiple views are taken on a single receptor plate, which of the following could result in a dark digital image?
segmentation failure
3. The heart of the PAC system, which directs all data, is a:
server
2. The centralized storage and distribution services of a PAC system are classified as a(n):
service class provider
22. The amount of space charge generated at the cathode is controlled primarily by the:
set amperage
25. Compared to single-phase generators, three-phase generators require only one-half of the:
set mAs
2. Beam-part-receptor alignment is the primary control for image:
shape distortion
When using an increased OID, which of the following is not affected:
shape distortion
2. Which of the following should always be maximized:
sharpness
2. In the remnant x-ray beam signal, which of the following is not affected by scatter radiation?
sharpness of detail
30. The equilibrium established by balancing of the collective repulsion of the electron cloud around the filament with the rate of electron emission by the filament is called the:
space charge effect
5. Every image begins and ends in the __________ domain:
spatial
6. Point, area, and global operations are all subcategories within the ________ domain:
spatial
19. The smallest object size that can be resolved in a radiographic image is inversely proportional to one-half of the:
spatial frequency
31. The reflection of a light bulb that is behind the observer, from the surface of a display monitor is classified as:
specular reflectance
41. Nearly all modern CR and DR systems can be operated at a ________ of 350 or 400 without the appearance of substantial mottle in the image.
speed class
11. Which shape of object produces the worst case of absorption penumbra:
spherical
7. When calculating for areas, both units and calculations must be:
squared
31. Which of the following is most likely to result in visible grid lines:
stationary grid
9. For an active-matrix LCD, light from fluorescent bulbs or LEDs is able to pass through the LCD panels when the nematic crystals in between them are:
twisted 90 degrees
4. A parallel circuit is one in which:
two or more devices are connected across different branches
3. To block out all light, place:
two polarizing lenses perpendicular to each other
2. When it is determined that air-fluid level demonstration is a priority, _____ projection may be required for _____.
two; air-fluid levels and a normal projection of the chest.
12. For a single-phase x-ray machine, about what fraction of the peak kV is the average kV:
½
21. A 60-watt light bulb is turned on in your home with 120 volts of force supplied from the plug. The light bulb must be using:
½ amp of current
