RADT 1075 Final
The optical density range visible to the human eye is
0.25 to 2.50
How many bytes are needed to store one alphanumeric character?
1
If a particular radiographic exposure requires 50 mAs and the 400 mA station is selected, what exposure time is required?
1/8 second
A perfect image processing system would have an MTF of:
100%
The magnification factor for a radiographic procedure is calculated as 1.25. It may be assumed that there is a ____ magnification of the object size.
125%
Which rule is used as a guide to maintain the same density when kVp changes?
15% rule
increasing kVp from 85 to 98 kVp
15% rule
The first version of DICOM was completed in:
1985
The minimum change necessary to cause a visible shift in density is ___% of mAs.
25-35
After completing a radiograph using 27 mAs at 90 kVp, the image demonstrates adequate overall density but an area that is under penetrated. In order to produce an optimum image in terms of contrast and penetration, the repeat image should be taken at
27 mAs and 100 kVp
A chest radiograph is produces with sufficient optical receptor exposure using 10 mAs at 72 inches. If the same radiograph is performed at 44 inches SID, what new mAs should be used to produce the radiograph with the same receptor exposure?
3.7 mAs
The k-edge of phosphor imaging plates ranges from _____ keV.
30 to 50
How many bits make up four bytes?
32
In order to achieve a true SID of 40" with an x-ray tube angle of 30 degrees, the overhead scale should read
34.6 inches
Depending upon kVp range, a visible change in contrast will not be seen unless kVp is minimally changed
4-12%
The range of kVp that can be used with PSP systems is:
40 to 120
If a PC had a 5.0-GHz CPU, it would have a system clock that would tick _______ billion times per second.
5
The grid conversion factor for a 12:1 grid is:
5
The wavelength of the PSP reader laser is ________ nm.
633
A pixel bit depth of 2 to the 16th power will demonstrate _________ shades of gray.
65,536
A server is:
A computer that manages resources for other computers.
Which of the following describes a thick-client computer?
A computer that works independently of the network.
Which examination does not exhibit an inherently large OID?
AP lumbar spine
When the imaging plate is irradiated, stimulated electrons enter the _______ layer.
Active
Which of the following describes a thin-client computer?
Any computer that needs a server for task completion
Which statement is FALSE?
As mAs decreases, exposure increases.
All of the following use buses that are found within the computer except the:
BCBV
The series of connections, controllers, and chips that create the information highway within the computer system is known as the:
BUS
UNIX was developed by:
Bell
A device that acts like a camera in an indirect conversion detector is known as a:
CCD
A detector in which each pixel has its own amplifier is known as a:
CMOS
Which of the following flat-panel detector technologies was developed by NASA?
CMOS
X-ray tube angulations inherently
Change the SID and introduce magnification to some degree.
kVp controls the proportional relationship
Compton and photoelectric interactions
H & D curve
D log E
If you increase beam restriction/collimation, what happens to density/receptor exposure?
Decreases
_________ represents how close the dots are located to one another within a pixel.
Dot pitch
(T/F) Automatic rescaling can be substituted for appropriate technical factors.
False
(T/F) Historical study patient examinations can be accomplished through the manual send function.
False
(T/F) Image aliasing is similar to the moire effect caused by grid error.
False
(T/F) It is possible to achieve an MTF of 100%.
False
(T/F) MTF is a way to quantify the contribution of each system component and the component's overall efficiency.
False
(T/F) No matter where the orientation stickers or labels exist on a digital cassette, the image will display correctly.
False
(T/F) Shuttering removes the dark exposed border, reducing the amount of information to be stored.
False
Which of the following has NO impact on radiographic contrast?
Focal Spot size
Which of the following has NO impact on radiation exposure to the patient?
Focal spot size
Which of the following require more critical beam centering?
Focused grids
The number of grid lines per centimeter or lines per inch describes grid:
Frequency
What metal is contained behind the outer layers of a DVD?
Gold
The air gap technique can be used as an alternative to:
Grids
The system that contains patient information, billing records and inpatient orders is the:
HIS
Which statement best describes a charge-coupled device?
It is the oldest indirect conversion technology used in a variety of image capture applications.
The least expensive network to install is a:
LAN
measures accuracy of image compared to original object
MTF
As the spatial frequency of objects increases,
MTF decreases
the quotient of SID over SOD
Magnification Factor
Resolution is improved when
OID decreases
Large patients receive a greater exposure than small patients because their
OID is increased, SOD is decreased, entrance skin surface is closer to the source.
"Write once, read many" is represented by which of the following identifiers?
R
The fastest and most versatile port is the:
SCSI
Devices commonly referred to as roles include:
SCU
All of the following affect visibility of detail EXCEPT
SID
Resolution is improved when
SID increases
Penumbra decreases as
SID increases, OID decreases, and focal spot size decreases
Size distortion is controlled by
SID, OID, and radiographic distances.
Magnification Factor
SID/SOD
SID/Magnification Factor
SOD
The most popular base material used in integrated circuits is:
Silicon
Image receptor contrast is expressed as the ______ of the D log E curve.
Slope
Proper patient demographic input is the responsibility of the:
Technologist
Which of the following statements about scintillators is true?
The amount of x-rays absorbed depends on the type of scintillator.
A device that includes a photosensitive array and small pixels that convert light into electrical charges is known as a ________ transistor.
Thin-film
(T/F) Air kerma is the measurement of radiation energy absorbed in a unit of air.
True
(T/F) Basic workstation functions include contrast manipulation, edge enhancement, and smoothing.
True
(T/F) The shape of the histogram is anatomy specific.
True
A technologist can lend credibility to his or her expertise by:
Using personal position markers.
The anode heel effect is more pronounced with
a 10 degree target angle
Which radiograph exhibits the best detail?
a PA chest radiograph for evaluation of the heart at 72 in.
In general radiography, quantum noise is
a function of mAs and kVp.
The brightness of the image on a viewing monitor is
a function of the monitor
Which generator produces the greatest amount of radiographic density per mAs?
a high-frequency generator
Raw data used to form the image histogram are compared with:
a normal histogram of the anatomic part
Photoconductors are materials that:
absorb x-rays and produce electrical charges.
The layer of the imaging plate that traps electrons during exposure is the ________ layer.
active
inadequate sampling of incoming data on a monitor
aliasing
If the entire range of exposure were digitized, pixel values representing ______ would be digitized.
all values
The type of flat-panel detector that uses thin films of silicon integrated with arrays of photodiodes is known as a(n):
amorphous silicon detector
Quantum efficiency is a measurement of the:
amount of electrons produced relative to the incident light from the scintillator.
When digital imaging receptors are used,
an exposure at 90 kVp would require a grid.
The exposure indicator number is:
an indication of radiation absorbed by the imaging plate.
The workstation function that allows selection of preset terms or manual text input is termed image:
annotation
variation in beam intensity along the long axis of beam
anode heel effect
In an effort to display the pixels for the area of interest when exposure is greater or less than what is needed to produce an image, _______ occurs.
automatic rescaling
A change in kVp, as an exposure factor, affects
average beam energy, the amount of scatter production, and beam intensity
The phosphor layer is made of phosphors from the ______ family.
barium fluorohalide
When insufficient light is produced by the imaging plate phosphor, the image will:
be grainy
A severely underexposed image will
be unable to visualize recorded detail
The total amount of irradiated material is a function of
body part thickness and area of exposure
During laser beam formation, both ends of the laser reflect energy back and forth so that the atoms:
bombard each other
When evaluating the degree of resolution on an actual radiographic image, an effective tissue to analyze is
bony trabecular pattern.
How dark or light a digital image appears on a display monitor is known as:
brightness
Image level parameters control image:
brightness
A renal calculus that measures 0.2 mm in size
cannot be visualized with an effective focal spot of 0.5 mm focal spot due to penumbral overlap.
Which of the following statements is not true?
changing the matrix and the FOV will not change the size of the pixel
Detector elements are formed by voltage gates that _______ at readout to _______ the flow of electrons.
close; allow
In the binary code, the value of one is assigned when a transistor is ________ and the current _________ through.
closed;passes
Cable consisting of a center conducting wire surrounded by insulation and a grounded shield of braided wire is called:
coaxial
The imaging plate layer that absorbs stimulating light and reflects emitted light is the ______ layer.
color
Two or more objects sharing resources and information or computers, terminals, and servers interconnected by communication channels is a definition of a:
computer network, wide area network (WAN), local area network (LAN).
Changing the slope of the look-up table graph will increase or decrease:
contrast
Detector performance is measured with all of the following except:
contrast
Window width controls the ratio of black and white, also known as:
contrast
The 15% rule changes
contrast and density
The ability of a digital system to display subtle changes in shades of gray is called:
contrast resolution
Changing the steepness of the exposure gradient:
controls image contrast
Using an FOV that is much larger than the part being examined will:
decrease resolution
If you decrease kVp, what happens to density/receptor exposure?
decreases
Collimation to a smaller area:
decreases compton interactions
The improper algorithm application may result in:
degradation of the imaging.
direct relationship between mAs and distance
density maintenance formula
The number of bits per pixel is known as bit:
depth
The efficiency of a system to convert x-ray input signal into a useful output image is known as:
detective quantum efficiency
Multiple numeric values divided into an array of small elements capable of being processed is the definition of ______ images.
digital
The effect of mAs upon IR exposure is
directly proportional
The optical mirror in the reader:
directs the laser beam to the imaging plate surface.
A system's ability to respond to varying levels of exposure, resulting in more detail, is referred to as:
dynamic range
The concept of contrast as it is displayed on a soft-copy monitor for digital images is described as
dynamic range
Amplification of the frequencies of the areas of interest is known as:
edge enhancement
The system that holds a specific patient's lab results, radiology reports, and physician's notes is the:
electronic medical record (EMR)
Which of the following occurs when the tube or image receptor is not properly aligned?
elongation
Contrast decreases with
excessive density, inadequate density, a wider range of densities.
Which of the following statements is not true?
exposure index refers to the amount of exposure to the patient
Which one of the following serves to protect against static build-up, dust collection, and mechanical damage to the imaging plate?
felt material
The most fragile type of network connection is:
fiber optic
The network connection that uses glass threads to transmit data is:
fiber optic
A device that acts like a switch to send electrical charges to the image processor in a direct conversion flat-panel detector is known as a _______ transistor
field-effect
The refresh rate controls the:
flicker
All of the following factors would affect radiographic contrast EXCEPT
focal spot selection
Factors affecting recorded detail include
focal spot size
Which of the following has NO impact on receptor exposure?
focal spot size
small and large
focal spot size
Which one of the following occurs when the part is improperly aligned?
foreshortening
The _____ the SID, the _____ the magnification.
greater;smaller
A radiograph that demonstrates considerable differences between densities is called
high contrast
A radiograph with few shades of gray exhibit
high contrast
When choosing between two radiographic grids, the k factor is different. Choosing a grid with the higher K factor will produce an image with
high contrast
fewer shades of gray across the final image
high contrast
Which generator type results in the GREATEST DECREASE IN CONTRAST?
high frequency
When the tissue structure of the ankle joint is considered, the dramatic tissue differences between the muscles and the bones of the ankle produce
high subject contrast
Data collected within the collimator are represented by a:
histogram
A GUI is best known as a(n):
icon
The selection of the incorrect body part from the examination menu may result in:
image misinterpretation
Grid use for PSP examinations is more critical than in film/screen radiography because CR:
imaging plates record more densities
Focal spot and OID affect image sharpness ______ imaging.
in both film/screen and digital
Slow film-screen combinations
increase resolution
Which of the following can be done to decrease the change of having image lag occur in the next image?
increase the amount of time between exposures.
If you increase density/receptor exposure, density is
increased
A radiograph that demonstrates considerable differences between densities is called
increased contrast, high contrast, short scale.
All of the following will increase radiographic film density EXCEPT
increased dryer temperature
Contrast increases with all of the following EXCEPT
increased scatter
As OID increases and SID remains constant, entrance skin exposure (ESE)
increases
As size distortion decreases, the resolution of recorded detail
increases
As the anatomical part size increases, the amount of scatter created by the part
increases
In digital imaging systems, increasing sampling frequency of the data.
increases image fidelity.
Most radiographers will use more exposure than required for a procedure. This does what to patient exposure?
increases patient exposure
As tissue density increases, the amount of scatter ______, which also results in a _________ in contrast.
increases, decreases
As the slope of the D log E curve _______, contrast _______.
increases, increases.
As kVp _____, a ______ range of photon energies is produced
increases, wider
As kVp increases, the percentage of Compton interactions _______ and contrast ______.
increases; Decreases
Which of the choices below DOES NOT increase contrast?
increasing the amount of irradiated tissue
Quantum mottle is caused by:
insufficient light
The density maintenance/direct maintenance formula mathematically resembles the
inverse square law
The relationship between exposure and SID is
inversely proportional to the square of the distance
Which can negatively impact recorded detail?
involuntary motion
Because of the "heel effect", x-ray beam intensity
is greater under the cathode side of the tube
Imaging noise is different from quantum noise in that imaging noise
is inherent in the imaging system
The principal controlling factor of contrast is
kVp
Which factor influences the average energy of photons reaching the IR?
kVp
controls the average energy of the x-ray beam
kVp
In order to reduce patient entrance skin exposure (ESE), higher kVp exposures are a consideration. It is important to remember that
kVp values that are too high produce more scatter and reduce contrast
Best seen with the patient supine
kidneys
Examinations of body parts with a large inherent OID warrant a ______ whenever possible.
large SID
Which of the following does not determine PSP resolution?
laser scan speed
The range of exposure values the image detector is able to produce is known as:
latitude
The image reader scans and reads the image from the:
leading edge of the imaging plate to the opposite end.
PSP imaging plates are erased by flooding the plate with:
light
The unit of resolution in film/screen imaging is
line pairs per millimeter
Proper patient demographic input ensures:
linking of all the patient's files
low contrast
long scale contrast
A radiograph that demonstrates minimal differences between densities is called
long scale, decreased contrast, low contrast.
The more manipulation of the image, the greater the:
loss of information
switching from 10:1 grid to 6:1 grid
loss of visibility of detail
A radiograph that demonstrates minimal differences between density shades is called
low contrast
many shades of gray across the final image
low contrast
Which type of radiograph provides the most information?
low contrast images
If too few pixels are sampled, the result will be:
low resolution
Averaging the frequency of each pixel with surrounding pixel values to remove high-frequency noise is called:
low-pass filtering
The more light spread, the _______ the MTF
lower
The principal controlling factor of radiographic image density is
mAs
Which factor influences the number of photons reaching the IF?
mAs
controls x-ray beam quantity
mAs
As you analyze your image, you come to the conclusion that it must have more exposure. As a general rule, you should increase
mAs by 2x
Size distortion in radiography can be ____ only.
magnification
The best method for controlling motion when the patient is unable to cooperate is to
maintain mAs, while decreasing time.
The ability to send images to local network stations can be accomplished using the:
manual send function
The size of the pixel is determined by the:
matrix
Spatial resolution in digital imaging is determined by the
matrix size, pixel size, and bit depth.
A histogram displays the useful signal by locating:
maximum signal only.
Failure of the reader to find the collimation edges of an image:
may cause the image to be too bright or too dark.
Because the x-ray beam is divergent,
minification is impossible
All of the following are common SCSI devices except the:
modem
Which measures the accuracy of an image compared to the original object on a scale of 0 to 1?
modulation transfer function
"The sum of the components in a recording system cannot be greater than the system as a whole" is a definition of:
modulation transfer function (MTF).
The longer an image is stored in the computed radiography (CR) cassette, the:
more energy is lost by the electrons.
What should you expect to occur with a decrease in kVp?
more photoelectric interactions
The higher the kilovoltage peak, the:
narrower the histogram
In a bus network:
no switches of hubs are necessary
Amplifiers perform all of the following functions except:
noise cancelling
If you change the focal spot from small to large, what happens to density/receptor exposure?
nothing happens
Milliampere-seconds (mAs) is selected for the:
number of electrons needed.
Ratio between image size and Magnification
object size
A dot triad is a grouping of:
one green dot; one blue dot; and one red dot
Binary code is a computer language based on:
ones and zeros
To effectively take advantage of the anode heel effect, where should the thicker part of the anatomy be placed?
over the cathode
In the event of making a single exposure that is critical to the exam success, most experienced technologists will
overexpose the IR slightly, provide enough exposure to permit viewing with a bright light or adequate histogram.
inherently magnified in AP projections
patella
The purpose of the barcode label is to match the image information with the:
patient identifier
The greatest factor in the production of scatter radiation is
patient thickness
Focal Spot Size X OID divided by SOD
penumbra
Poor resolution is caused by unacceptable levels of
penumbra.
Proper alignment is achieved when the central ray is ____ to the part and ______ to the image receptor.
perpendicular, perpendicular
Resolution with intensifying screens will increase as _______ increases.
phosphor concentration
Ethernet protocol performs at the _______ layer.
physical
Each square in a matrix is called a:
picture element
Intermittent extraneous line patterns are ______ artifacts.
plate reader
Performing a routine chest radiograph in the AP projection will
produce improved resolution in the thoracic spine.
Scintillators are phosphors that:
produce light when absorbing x-rays
only corrected by increasing mAs
quantum mottle
results from insufficient mAs
quantum noise
The difference between two adjacent densities is
radiographic contrast
require an increase in mAs as ratio increases
radiographic grids
RIS is specific to:
radiology
You have completed a chest radiograph on a 2-month-old infant using a restraining device at a 72" SID. Because of the design of the device, your OID is suboptimum. The image reveals good resolution of the bony anatomy but the pulmonary vasculature is blurred. The EI value is 2040. In an effort to improve the quality of the repeat image, the competent radiographer would
raise the mA and decrease the exposure time.
The laser scans the imaging plate in a ______ pattern.
raster.
An increase in x-ray beam filtration
reduces contrast, increases the number of compton interactions, increases the average photon energy.
Demagnification is:
reducing the phosphor output image to the size of the active area of the CCD
Grid ratio describes the:
relationship between the height of the lead strips to the interspace
Cracks in the imaging plate can be caused by:
removing and replacing the plate in the reader
When the position of the patient is reversed, the direction of the tube angle must be ___ to maintain the relationship
reversed
The overall general shape of human anatomical structures are
round or oval
Critical characteristics of a digital image include all of the following except:
sample resolution.
The Nyquist frequency is
sampling a minimum of twice per cycle
The Nyquist theorem states that the:
sampling frequency must be twice the input signal bandwidth.
A wraparound image or image aliasing occurs when:
sampling occurs less than twice per cycle
A network switch:
sends data only to data-directed devices.
A network that uses a central computer that sends the entire original resource to the client is known as a:
server-based network
A look-up table is not used as a reference to:
set appropriate kilovoltage peak and milliampere-seconds values.
A fluoroscopic examination that uses barium as a contrast material would typically produce images with
short scale contrast
high contrast
short scale contrast
RAM is:
short term for open programs
Input of annotation for identification of the patient's left or right side:
should be used in conjunction with the technologist's anatomy markers.
Lossy compression is used to:
shrink file size
An image manipulation process that fills in the background so that it is darkened is known as:
shuttering
Distortion is a misrepresentation of
size and shape
Which of the following should be considered when selecting the PSP cassette?
size and type
low-pass filtering is also known as:
smoothing
Defective pixels can result from all of the following except:
software programs
The amount of detail present in any image is known as ______ resolution.
spatial
The ability of an imaging system to demonstrate small details of an object is known as:
spatial resolution
The process of joining two or more images into one continuous image is known as image:
stitching
contributing factor to total image contrast
subject contrast
The recorded detail of a radiographic image is visible because of
sufficient density, sufficient contrast
An archive query retrieves images from the PACS based on any of the following except:
technologist anatomical number
All of the following are considered impurities except:
tellurium
When sampling frequency is less than the Nyquist value
the Moire effect can occur
Recorded detail is
the accuracy of the structural lines actually recorded in the radiographic image, the degree of geometric sharpness and definition
As a last resort, which human immobilizer is used to hold a patient in position?
the male relative
High contrast is directly related to
the number of photoelectric interactions
Opening up the intervertebral joints of the cervical spine would best be accomplished with
the patient in an AP projection with a 40" SID
For general radiography, an MTF value of 1 is
theoretically impossible
In CsI detectors:
there is very little light spread
CsI detectors use:
thin crystalline needles
Kilovoltage peak (kVp) should be chosen:
to provide penetration
If all of the shades were left in an image after processing, the contrast would be:
too low
Coherent light is formed by the laser because the photons:
travel in the same direction
As focal spot size decreases,
umbra is improved, resolution increases, and penumbra increases
Possible causes of image lag include all but:
underexposure.
Automatic rescaling means that images are produced, regardless of the amount of exposure, with:
uniform contrast and density.
The system clock uses a:
vibrating quartz crystal
affected by photographic properties of image
visibility of detail
A digital detector with a high fill factor
will produce high resolution
Image brightness on an image display monitor is controlled by
window level
Flat-panel detectors that use indirect conversion technology convert:
x-rays to visible light
The ____ represents a depth to the information in the digital image
z axis
Magnification of the entire image at the workstation is termed:
zoom