Image Production

The ionization chamber in an automatic exposure control (AEC) general radiography machine is located: A. between the tube and the patient. B. between the patient and the receptor. C. behind the image receptor. D. below the Bucky tray.

between the patient and the receptor

In digital radiography, spatial resolution depends on: A. pixel size. B. bit depth. C. window level. D. dynamic range.

pixel size.

The sampling frequency of an imaging system determines the: A. pixel size. B. bit depth. C. dynamic range. D. detective quantum efficiency.

pixel size.

The allowable deviation for the light field to x-ray beam congruency test is ________ % of the source-to- image distance (SID). 0.5 2 5 10

2

When the kVp is increased, the: A. histogram width narrows. B. pixel size increases. C. data range widens. D. magnification decreases.

histogram width narrows

No practical amount of mAs can compensate for inadequate: A. exposure time. B. kVp. C. source-to-image distance (SID). D. grid ratio.

kVp

In fluoroscopy, image brightness results from ________ gain. 1. minification 2. modulation 3. flux 1 and 2 1 and 3 2 and 3 1, 2, and 3

1 and 3

Which of the following are advantages to using a fixed kVp/variable mAs chart? 1. Part measure is not critical. 2. Radiographic contrast is inherently short scale. 3. The patient dose is lower. 1 and 2 1 and 3 2 and 3 1, 2, and 3

1 and 3

A shallower target angle creates: 1. a smaller effective focal spot. 2. a smaller actual focal spot. 3. greater recorded detail. 1 and 2 1 and 3 2 and 3 1, 2, and 3

1 and 3 - a shallow target angle creates a large actual focal spot size and small effective focal spot size - recorded detail increases as the effective focal spot size decreases

A histogram can: 1. show the number of pixels within a certain value. 2. serve as a point processing function. 3. calculate the exposure index. 1 and 2 1 and 3 2 and 3 1, 2, and 3

1, 2 and 3

Spatial resolution increases as: 1. object-to-image distance (OID) decreases. 2. source-to-image distance (SID) increases. 3. penumbra decreases. 1 and 2 1 and 3 2 and 3 1, 2, and 3

1, 2, and 3

A bit can be assigned one of how many possible values? 2 4 6 8

2 - a bit is also called a binary digit, indicating 2 possible values. A bit can be assigned a value of either "0" or "1"

Which of the following lowers radiographic contrast? 1. increase in photoelectric effect 2. 15% increase in kVp 3. increase in field size 1 and 2 1 and 3 2 and 3 1, 2, and 3

2 & 3

Tungsten is an excellent choice for anode material because of its: 1. Low atomic number. 2. High melting point. 3. Heat-conducting ability. 1 and 2 1 and 3 2 and 3 1, 2 and 3

2 and 3

Which of the following are properties of positive contrast agents? 1. composed of low-atomic number elements 2. increase x-ray attenuation 3. produce areas of decreased density on the image A. 1 and 2 B. 1 and 3 C. 2 and 3 D. 1, 2, and 3

2 and 3 - contrast agents typically are classified as positive (radiopaque) or negative (radiolucent) - positive contrast agents are composed of high-atomic number elements, increase x-ray attenuation, & produce areas of decreased density on the image

The exposure field size and image receptor size selected must be within _____ of the source-to-image distance. 1% 2% 3% 5%

2%

The source-to-image distance (SID) indicator is allowed a _____ variation. 1% 2% 5% 10%

2%

How many transformers from the list below work based upon mutual induction? 1. air core transformer 2. open core transformer 3. autotransformer 4. closed core transformer 1 2 3 4

3 - mutual induction requires the presence of 2 separate coils of wire - air core, open core, and closed core are made up 2 coils of wire - an autotransformer consists of a single coil of wire and works by self-induction

Which of the following x-ray generators will yield the highest tube output if an exposure is made using 75 kVp and 12 mAs, and all other factors are equal? A. 3-phase, 6-pulse B. single-phase, full-wave C. 3-phase, 12-pulse D. single-phase, half-wave

3-phase, 12-pulse - will yield the highest tube output because it has the lowest voltage ripple (approximately 3.5%) - single-phase generator has a 100% ripple factor - 3-phase, 6- pulse generator has approx. a 13% ripple

A(n) ________-bit computed radiography/direct radiography (CR/DR) system would have the highest contrast resolution. 8 12 16 32

32

A 3-phase, 6-pulse generator produces ________ pulses/second. 60 120 360 720

360

The rotating anode target material that is responsible for helping to cool and conduct electrons through the x-ray circuitry is comprised of how many materials from the list below? Tungsten Thorium Rhenium Molybdenum Graphite 1 2 3 4

4 (all except Thorium)

Exposure between automatic exposure control (AEC) sensors of a multiple-sensor system should vary no more than: 1%. 2%. 5%. 10%.

5%

Exposure reproducibility is allowed a ________ variation. 1% 2% 5% 10%

5%

The minimum luminance resolution for primary display workstations is ___-bit. 6 8 10 12

8

A(n) ________-bit CR/DR system would demonstrate the fewest shades of gray. A) 8 B) 12 C) 16 D) 32

8 - the lower the bit depth the fewer shades of gray available to display

________ is used as interspace material in grids. Aluminum Copper Lead Molybdenum

Aluminum - Aluminum is used as interspace material because of its low attenuating properties and the ability to easily cut and shape it. Additionally, aluminum is a relatively inexpensive material.

The number of electrons flowing in a conductor is measured by the: Ampere. Ohm. Volt. Coulomb.

Ampere - one amp is equal to 6.24 x 10 18 electrons flowing past a fixed point in one second

Incoming line voltage is first adjusted by the: A. Step-up transformer. B. Step-down transformer. C. Closed transformer. D. Autotransformer.

Autotransformer

An image is acquired using 75 kVp with 3 active automatic exposure control (AEC) cells. A second image is acquired with 121 kVp with 3 active AEC cells. How will the receptor exposure differ between the images? A. Image 2 will have higher image receptor exposure. B. Image 2 will have lower image receptor exposure. C. Both images will have similar exposures. D. AEC use has no effect on image receptor exposure

Both images will have similar exposures - the AEC is used to maintain exposure to the image receptor; both image 1 and 2 should have similar receptor exposures

Select the statement below that is TRUE regarding multifield image intensifiers. A. Minification gain is lowest when using the largest field. B. Patient dose is lowest when using a smaller area of the input phosphor. C. Brightness gain increases when a larger area of the input phosphor is used. D. Input phosphor size remains constant and output phosphor size varies.

Brightness gain increases when a larger area of the input phosphor is used - the larger the area of the input phosphor used the greater the brightness gain.

Which of the following is the unit of measure for display monitor luminance? Cd/m2 mGy/s Lp/mm Lines/cm

Cd/m2

_______ ratio compares signal intensity difference between 2 regions of interest to noise.

Contrast-to-noise

Select the statement below that is TRUE regarding multifield image intensifiers. A. Minification gain is greatest when using the largest input field. B. Patient dose is lowest when using a smaller area of the input phosphor. C. Brightness gain decreases when a larger area of the input phosphor is used. D. Input phosphor size remains constant and output phosphor size varies.

Minification gain is greatest when using the largest input field

________ is the measure of image resolution from a digital detector system. A. Modulation transfer function (MTF) B. Automatic exposure control (AEC) C. Detective quantum efficiency (DQE) D. Detector element (DEL)

Modulation transfer function (MTF)

Which of the following statements is TRUE? A. Adding filtration to the beam increases receptor exposure. B. Beam energy decreases when filtration is added. C. Photoelectric absorption increases with increased filtration. D. Receptor exposure can be reduced by adding filtration to the beam.

Receptor exposure can be reduced by adding filtration to the beam - addition of filtration to the beam reduces receptor exposure from the removal of photons from the beam

An image was acquired using 70 kVp with 3 active automatic exposure control (AEC) cells. A second image was taken with 100 kVp and 3 active AEC cells. How will the mAs read-out differ between images? A. The mAs for image 1 will be higher. B. The mAs for image 2 will be higher. C. Both images will have similar mAs read-outs. D. AEC use does not affect mAs.

The mAs for image 1 will be higher - if a high kVp is used while the AEC is active, the time necessary to terminate the exposure is reduced, which reduces mAs - a high mAs would be generated if a low kVp is used

An image was acquired using 70 kVp with 3 active automatic exposure control (AEC) cells. A second image was taken with 100 kVp and 3 active AEC cells. How must the technologist set mAs to maintain receptor exposure from Image 1 to Image 2? Set mAs higher for Image 2. Set mAs lower for Image 2. Use similar mAs for both images. The technologist does not set mAs when using the AEC.

The technologist does not set mAs when using the AEC.

All of the following increase the contrast-to-noise ratio (CNR) EXCEPT: A. a larger field size. B. a higher grid ratio. C. lower kilovoltage. D. a shorter object-to-image distance (OID).

a larger field size - a larger field size will decrease the contrast-to-noise ratio - this is due to an increase in the volume of irradiated tissue, which results in an increase in scatter production - scatter is noise & results in a decrease in contrast

What semiconductor material is used in indirect flat panel imaging detectors? A. amorphous silicon B. gadolinium oxybromide C. amorphous selenium D. barium fluorohalide

amorphous silicon

A coil of wire wrapped around a ferromagnetic rod is: A. an electromagnet. B. a solenoid. C. a resistor. D. a rheostat.

an electromagnet

Which component is responsible for digitizing the CR analog signal? A. PSP B. laser C. analog-to-digital converter D. fiber optics

analog-to-digital converter - the laser releases the image data from the PSP plate - light that is released from the plate is sent to a photodetector via the fiber optics - the photodetector produces an analog signal that is sent to the analog-to-digital converter to be digitized

The device responsible for quantization during the PSP plate reading process is the: A. light guide. B. photomultiplier. C. analog-to-digital converter (ADC). D. laser.

analog-to-digital converter (ADC)

The variation in x-ray tube output along the long axis of the tube is best described by the: A. inverse square law. B. anode heel effect. C. line focus principle. D. Nyquist theorem.

anode heel effect - the anode heel effect describes the effect of anode construction that results in a greater beam intensity on the cathode end of the x-ray tube compared with the intensity on the anode end of the x-ray tube

All of the following are examples of postprocessing functions EXCEPT FOR: A. edge enhancement. B. smoothing. C. electronic masking. D. automatic rescaling.

automatic rescaling

The formula 2n represents: A. bit depth. B. pixel size. C. field of view. D. matrix size.

bit depth

Contrast resolution increases from an increase in: A. pixel size. B. bit depth. C. field of view. D. pixel pitch.

bit depth - contrast resolution is the ability of the imaging system to depict low-contrast objects - bit depth determines the number of gray shades available for image display - as the number of gray shades increases, so does the contrast resolution

The quantization of image data is dependent upon: A. sampling frequency. B. pixel size. C. bit depth. D. pixel density.

bit depth - quantization is the process of assigning a numerical value to each pixel in the image - the bit depth of an imaging system determines the range of numerical values that can be assigned

Contrast resolution of a CR/DR image is determined by the _____ of the system. A. matrix size B. bit depth C. sampling frequency D. dynamic range

bit depth bit depth controls the gray scale of the image

Automatic exposure rate control (AERC) maintains a constant: A. milliamperage. B. kilovoltage peak. C. brightness. D. veiling glare.

brightness - purpose of automatic exposure rate control is to maintain image brightness as fluoroscopy unit is moved over anatomical structures of varying thicknesses & composition - AERC typically maintains brightness by altering the mAs, kVp or both

All of the following are components of an image intensifier EXCEPT FOR the: A. input phosphor. B. anode. C. capacitor. D. photocathode.

capacitor - capacitors are NOT components of an image intensifier - the input phosphor converts x-rays to light; the photocathode converts light to electrons and the anode accelerates the electrons toward the output phosphor

The portion of the x-ray tube that is associated with the filament and focusing cup is the: A) anode. B) bearing. C) cathode. D) rotor.

cathode - the negative side of the x-ray tube (cathode) comprises the filament & focusing cup

Which image display monitor works by accelerating electrons toward a fluorescent screen? A) liquid crystal display B) cathode ray tube C) thin-film transistor D) photostimulable phosphor plate

cathode ray tube - the liquid crystal display monitor works by light passing through liquid crystals to be displayed on a glass faceplate - the thin-film transistor and photostimulable phosphor plate are types of imaging detectors.

Light is directed toward a(n) ________ via a coupling device. A. photostimulable phosphor plate B. charge-coupled device C. indirect flat panel detector D. direct flat panel detector

charge-coupled device

The ________digital radiography indirect flat-panel receptor is a semiconductor that is susceptible to noise, but has a low fill factor. A. charge-coupled device (CCD) B. complementary metal oxide semiconductor (CMOS) C. photostimulable phosphor (PSP) D. thin-film transistor (TFT)

complementary metal oxide semiconductor (CMOS)

The fluoroscopic control switch requires __________ pressure to energize the x-ray tube. continuous intermittent variable prep and depress

continuous

The thickness of the object being imaged has the GREATEST effect on: A. motion. B. spatial resolution. C. distortion. D. contrast.

contrast

The source-to-image distance (SID) affects all of the following EXCEPT: A. receptor exposure. B. spatial resolution. C. contrast. D. distortion

contrast - SID does not affect contrast - altering SID will affect the quantity of radiation reaching the receptor - due to beam geometry, altering the SID will also affect image distortion & spatial resolution

An acceptable image is produced using a particular set of exposure parameters. The image is repeated using the air-gap technique with all other factors remaining constant. Given this scenario, all of the following will decrease EXCEPT: A) sharpness. B) receptor exposure. C) contrast. D) spatial resolution.

contrast - air-gap technique increases the object-to-image distance (OID) - increasing OID increases contrast b/c less scatter reaches the receptor - less scatter to the receptor also means that receptor exposure decreases - additionally, when the OID is increased, spatial resolution (sharpness) decreases.

When discussing the grid, the letter "K" represents the _____ a. grid ratio b. contrast improvement factor c. bucky factor d. selectivity

contrast improvement

________ is the ratio of image brightness from the edge to the center of the output screen. A. Signal-to-noise ratio B. Contrast ratio C. Conversion factor D. Vignetting

contrast ratio

On a radiograph of an osteoporotic spine, image ________ is ________ compared with an image of a nonosteoporotic spine. A. density; decreased B. contrast; lower C. contrast; higher D. resolution; decreased

contrast; lower

All of the following EXCEPT ________ can help reduce exposure to a morbidly obese patient. A. using positioning to reduce tissue thickness B. using secondary shielding C. decreasing kVp and increasing mAs D. using compression when appropriate

decreasing kVp and increasing mAs

Which of the following might cause an increase in quantum mottle (type of radiographic noise directly related to the # of x-ray photons exiting the patient & forming the radiographic image. Fewer photons reaching the image receptor will cause an undesirable fluctuation in image densities, resulting in images with a grainy, or sandlike, appearance)? A. increasing the mAs B. decreasing the field size C. increasing the filament size D. decreasing the grid ratio

decreasing the field size - decreasing field size might result in increased quantum mottle from a reduction in the amt. of scatter produced - even though scatter is useless information, it contributes to receptor exposure. - therefore, decreasing the field size can reduce scatter resulting in quantum mottle because of insufficient receptor exposure

The ________ exhibits the LEAST lateral signal spread of receptors. A) photostimulable phosphor plate (PSP) B) direct capture detector C) indirect capture detector D) complementary metal oxide semiconductor (CMOS) detector

direct capture detector - the direct capture detector exhibits the least divergent signal spread

Data sampling results in ________ data. analog continuous infinite discrete

discrete

Increasing the kVp by 15% has the same effect on receptor exposure as ________ the milliampere- seconds (mAs). halving doubling quartering quadrupling

doubling

The ________ grid pattern configuration transmits the greatest number of photons. A. linear parallel B. cross-hatch C. focused D. unfocused

focused

The _____ grid design is manufactured to match the divergence of the x-ray beam. parallel crossed linear focused

focused - focused grid has lead strips angled to be parallel w/ the divergence of the x-ray beam to reduce primary beam cut-off

Divergence of the space charge is prevented by the: A. vacuum. B. focusing cup. C. anode. D. filament.

focusing cup

The ________ is primarily composed of nickel. filament anode tube housing focusing cup

focusing cup

The ___________ controls the spread of the space charge. A. focusing cup B. anode C. glass envelope D. stator

focusing cup - the focusing cup is negatively charged to repel the space charge away from the cathode assembly; the cup is also parabolic in shape around the filament - this shape condenses the space charge and prevents its divergence as it leaves the assembly

The number of grid lines per unit length is the: Which of the following statements is TRUE? A) frequency. B) ratio. C) focus. D) interspace

frequency

The base layer of a flat-panal detector is made of: glass. lead. thorium. molybdenum.

glass

Which of the following represents the standard for displaying image contrast? A. American Association of Physicists in Medicine Task Group 18 (AAPM TG-18) B. SMPTE C. gray-scale standard display function (GSDF) D. PACS

gray-scale standard display function (GSDF) - AAPM TG -18 & SMPTE are test patterns for display monitors - PACS is a system for storing, transferring and displaying images

Increased conversion efficiency means a scintillator can create: A. higher electronic gain with a thicker phosphor layer. B. higher electronic gain with no change in phosphor layer thickness. C. lower signal spread with a thicker phosphor layer. D. lower signal spread with no change in phosphor layer thickness.

higher electronic gain with no change in phosphor layer thickness

When raw exposure data indicates overexposure or underexposure, the data can be processed using: A. image optimization. B. histogram rescaling. C. equalization. D. quantization.

histogram rescaling

As image compression ratio increases: A) image quality degrades. B) more image storage space is required. C) image transmission is slower. D) compression tolerance is not approached

image quality degrades - as compression ratio increases, some data is lost and image quality degrades - although less storage space is required in PACS for the file & transmission from PACS to display is faster, the use of large compression factors can cause loss of detail or compression artifacts

The selection of a small focal spot size helps to: A) increase spatial resolution. B) minimize motion blur. C) decrease entrance skin exposure. D) increase contrast resolution.

increase spatial resolution use of the small focal spot size is needed when an increase in spatial resolution is required.

Filament vaporization can result in all of the following EXCEPT for: A) decreased tube filtration. B) increased tube arcing. C) decreased tube output. D) increased average photon energy

increased tube arcing - as filament vaporizes, tungsten deposited on glass envelope; the metal deposits increase possibility of arcing (electrical discharge); as result, tube output decreases - additionally, the metal deposits act like a filter, which is analogous (comparable in certain respects) to increasing tube filtration - filtering out lower energy x-rays increases the average photon energy

A transformer that has a greater number of turns in the secondary side will result in: A. increased voltage. B. decreased voltage. C. increased amperage. D. decreased power.

increased voltage

A technologist acquires an image without a primary beam restrictor, and then repeats the image using the device. To maintain exposure to the image receptor for the second image, the technologist must modify the technical factors by: A) increasing technique. B) increasing source-to-image distance (SID). C) increasing focal spot size. D) increasing object-to-image distance (OID)

increasing technique - technical factors must be increased when photons are removed from the beam via field size restriction to maintain exposure to the IR

A radiographer acquires a knee radiograph using 200 mA; 0.10 sec; 80 kVp; 40-inch source-to-image distance (SID); and 12:1 grid. Which of the following would have the greatest effect on spatial resolution? A. increasing the kVp to 85 B. using an 8:1 grid C. increasing the SID to 60 inches D. using 0.05 seconds exposure time

increasing the SID to 60 inches - the increase in SID will increase spatial resolution

All of the following EXCEPT _____ will result in an increase in AEC response time. a. decreasing the kVp b. increasing the focal spot size c. increasing the part thickness d. increasing the source-to-image distance (SID)

increasing the focal spot size - Increasing focal spot size does not change AEC response time. It affects the spatial resolution. - Decreasing the kVp increases exposure time because more photons are absorbed, resulting in fewer reaching the cell(s). The same is true for increasing part thickness. - Increasing SID results in longer exposure time b/c of beam divergence & the decrease in the # of photons reaching the cell(s).

The _____ generator component converts DC current to high-frequency AC. capacitor rectifier transformer inverter

inverter - inverters convert DC to high-frequency AC (they are found in high-frequency generators) - rectifiers convert AC to DC - transformers increase or decrease voltage - capacitors smooth voltage waveform to reduce voltage ripple ( keep voltage across the tube relatively constant)

Modern automatic exposure control (AEC) sensors are of the ________ type. A. scintillator B. ionization chamber C. autotransformer D. phototimer

ionization chamber

The potential difference between the cathode and the anode is determined by which of the following? A) mA B) focal spot size C) time D) kVp

kVp - kVp is the force (voltage) that drives the electrons from the cathode to the anode - time & mA affect the number of electrons that flow from the cathode to the anode

The device responsible for the release of trapped electrons from the photostimulable phosphor (PSP) plate is the: light guide. photomultiplier. charge-coupled device. laser.

laser

Collimator shutters are made of: plastic. aluminum. lead.

lead

Which of the following coupling devices is used in conjunction with a CCD detector? A. lead strips B. copper wire C. magnets D. lenses

lenses

All of the listed functions express the boundaries of objects resolved by digital imaging systems, EXCEPT for: A. edge spread B. point spread C. line spread D. light spread

light spread

Spatial resolution is measured in: A. line pairs per mm. B. pixels. C. photons. D. gray scale.

line pairs per mm

When assessing mR/mAs with no more than a 10% variation between settings of adjacent mA stations, the radiographer is assessing: A. timer accuracy. B. linearity. C. reproducibility. D. screen-film contact.

linearity - the assessment of mR/mAs is the test for linearity between adjacent mA settings

What material is added to the anode to increase its thermal capacity? nickel iron molybdenum aluminum

molybdenum

The brightness of a given area on the digital image is represented by the: A. numerical value of a pixel. B. numerical value of a voxel. C. sum of the matrix. D. product of the matrix and voxels.

numerical value of a pixel.

A radiograph that demonstrates acceptable brightness along one side of the image but NOT on the opposite side represents a(an) _____ error. A. grid motion too slow B. upside-down focused grid C. incorrect grid ratio D. off-level grid

off-level grid - the off-level grid causes a portion of the grid strips to no longer align with the divergence of the x-ray beam - the area of the beam that does not match the angle of the lead strips is cut off

The device used to measure electrical resistance is the: ammeter. voltmeter. ohmmeter. capacitor.

ohmmeter

Image processing algorithms can partially compensate for improper automatic exposure control (AEC) use in all of the following EXCEPT: A. image density. B. image contrast. C. patient exposure. D. penetration of the part.

patient exposure

The blurred margin around structural edges is called: A. spatial resolution. B. quantum mottle. C. magnification. D. penumbra.

penumbra - penumbra occurs because x- rays do not originate from a point source, but rather from an area (focal spot)

The ________ collects the light emitted from the PSP during reading. analog-to-digital converter photomultiplier tube amplifier histogram

photomultiplier tube

The low-voltage side of the main x-ray circuit is on the: A. primary side of the step-up transformer. B. secondary side of the step-up transformer. C. primary side of the step-down transformer. D. secondary side of the step-down transformer

primary side of the step-up transformer

The outermost layer of the PSP plate is designed to: protect the phosphor. increase absorption of x-rays. amplify the energy of x-ray photons. reduce the scatter striking the plate.

protect the phosphor

In digital imaging systems, the MOST prominent visual feedback on the image regarding dose to the image receptor is: A. recorded detail. B. quantum noise. C. contrast. D. brightness.

quantum noise

The height of the lead strips divided by the distance between the lead strips defines grid: A. ratio. B. focusing distance. C. frequency. D. tolerance.

ratio

When the x-ray beam in NOT properly aligned with the grid strips the _____ is changed. a. spatial resolution b. sampling frequency c. receptor exposure d. distortion

receptor exposure - when the grid is not properly aligned with the x-ray beam the primary beam strikes the grid strips, leading to a decrease in receptor exposure. - the other items on the list are not affected when the beam and grid are not properly aligned.

Which of the following is classified as a type of diode? A. transformer B. rectifier C. capacitor D. resistor

rectifier - a diode is a device that allows electrons to flow in one direction; this is accomplished in the x-ray circuitry by rectifiers

If the source-to-image distance (SID) is doubled, the x-ray intensity at the image receptor is: A. increased 4-fold. B. doubled. C. reduced by one half. D. reduced to one fourth

reduced to one fourth

Radiation that exits the patient and is directed toward the receptor is referred to as _____radiation primary scatter secondary remnant

remnant - radiation that exits the patient consists of transmitted x-rays and scattered x-rays. Collectively, this is referred to as remnant radiation.

The spatial resolution of a detector is controlled by the: A. sampling frequency. B. matrix size. C. milliampere-seconds (mAs). D. analog-to-digital converter (ADC).

sampling frequency - the sampling frequency of the detector controls the spatial resolution of the device

In digital imaging, the proximity of signal selections to one another is known as: A. pixel pitch. B sampling pitch. C. field of view. D. sampling frequency.

sampling pitch

The accuracy of structural lines recorded in an image is referred to as: A. penumbra. B. distortion. C. spatial resolution. D. sharpness

sharpness

A ________ grid has lead strips that run perpendicular to the long axis of the grid. focused short dimension cross-hatched long dimension

short dimension

A detective quantum efficiency (DQE) of 1 indicates the: A. modulation of the input signal is larger than the modulation of the output signal. B. signal-to-noise ratio (SNR) of the input and output signals is equal. C. intensity and amplitude of both the input and output signals is equal. D. signal intensity output is equal to the noise intensity output.

signal-to-noise ratio (SNR) of the input and output signals is equal.

________ is the software function that removes high frequencies characteristic of noise. A. Smoothing B. Edge enhancement C. Equalization D. Gray-scale enhancement

smoothing

Which of the following affect the spatial resolution of an image? A. mAs and object-to-image distance (OID) B. source-to-image distance (SID) and focal spot size C. kVp and mAs D. tube angle and kVp

source-to-image distance & focal spot size - SID, OID, & focal spot size are geometric properties that affect image sharpness or spatial resolution - tube angle also affects image sharpness due to part magnification - mAs and kVp affect the visibility of spatial resolution.

A decrease in exposure time can increase image: A. density. B. contrast. C. distortion. D. spatial resolution

spatial resolution - a shorter exposure time reduces the chance of motion, which affects spatial resolution

Tube filtration affects all of the following EXCEPT: A. receptor exposure. B. spatial resolution. C. subject contrast. D. patient exposure

spatial resolution - filtration decreases patient exposure, receptor exposure, and subject contrast. It has no effect on spatial resolution.

Motion degrades: A. contrast. B. spatial resolution. C. receptor exposure. D. penumbra.

spatial resolution.

The effective focal spot size is affected by which of the following? A. anode rotation speed B. filament composition C. target angle D. anode heel effect

target angle - the anode, or target, angle affects the effective focal spot size; the smaller the anode angle, the smaller the effective focal spot size - there are limitations to how small the angle can be; if it's too small, the x-ray beam area might not be large enough to cover a large receptor size (i.e., 35 cm x 43 cm). - anode rotation speed helps w/ heat dissipation - anode heel effect results from the angling of the anode

Which of the following will NOT affect the effective focal spot size? A. filament size B. anode angle C. target material D. actual focal spot size

target material the target material affects heat capacity and x-ray production efficiency

Image noise can be reduced in digital fluoroscopy by using: A. last image hold. B. temporal subtraction. C. gray-scale image manipulation. D. temporal frame averaging.

temporal frame averaging

A modulation transfer function (MTF) of 1 indicates: A. the modulation of the input signal is larger than the modulation of the output signal. B. that signal-to-noise ratio (SNR) of the input and output signals is equal. C. the intensity and amplitude of the input and output signals is equal. D. the signal intensity output is equal to the noise intensity output.

the intensity and amplitude of the input and output signals is equal

Which of the following metals is added to the tube filament to extend its life? copper thorium rhenium molybdenum

thorium - extend its life by minimizing vaporization - rhenium & molybdenum are used in the anode - copper wiring is used in the induction motor

Density control adjustments alter: A. kVp. B. mA. C. time. D. automatic exposure control (AEC) cell selection.

time

Spatial resolution is increased in fluoroscopy through: A. use of magnification mode. B. increases in brightness gain. C. use of automatic brightness control. D. moving the intensifier further from the patient.

use of magnification mode - magnification mode allows for increased resolution of detail

A histogram is used to determine the: A. sampling frequency. B. pixel size. C. values of interest. D. bit depth

values of interest

Digital image brightness can be determined by: A. milliampere-seconds (mAs). B. window level. C. window width. D. pixel size.

window level

The radiographic brightness on a CR/DR image can be manipulated by changing the: A. window width. B. window level. C. matrix size. D. voxel volume.

window level

_____ is the local processing function of renumbering pixel values for an entire image domain. A. The look-up table (LUT) B. The histogram C. Equalization D. Windowing

windowing - windowing renumbers pixel values across the image domain.

The active layer of a direct flat panel detector converts: A. light to electrons. B. x-rays to light. C. electrons to light. D. x-rays to electrons.

x-rays to electrons - direct flat panel detectors have an active layer composed of amorphous selenium. This active layer absorbs x-rays and converts them to electrons

The ________ error is NOT likely to occur when working with a direct (digital) radiography flat-panel system. A. upside down B. off-focus C. angled central ray D. off-center

upside down - an upside-down grid error is not likely to occur when a grid is used with direct radiography flat-panel systems because the grid often is integrated into the image detector

The effect of grid use is minimized in fluoroscopy by: increased kVp. use of a higher grid ratio. use of a lower grid ratio. decreased mA.

use of a lower grid ratio

Exposure linearity is allowed a ______ variation. 1% 2% 5% 10%

10%

Digital image contrast can be determined by: 1. kilovoltage peak (kVp). 2. window width. 3. window level 1 and 2 1 and 3 2 and 3 1, 2, and 3

1 and 2

Alignment of the x-ray beam with the Bucky tray is allowed a ______ variation based on the source-to- image distance (SID). 1% 2% 5% 10%

1%

The HVL for a 60 kVp beam is ________ of aluminum equivalent (Al/eq). 1.3 mm 1.5 mm 2.3 mm 2.5 mm

1.3

Grids should be used on parts that are: A. 5 cm or smaller. B. 5 cm or larger. C. 10 cm or smaller. D. 10 cm or larger.

10 cm or larger

The fluoroscopic feature that maintains the signal-to-noise ratio (SNR) is abbreviated as: MTF. DQE. AERC. AEC.

AERC - the automatic exposure rate control (AERC) maintains the SNR

For conventional fluoroscopy, the light intensities must be converted by the _____ to be viewed on a television monitor. A. CCD B. electrostatic lenses C. output phosphor D. focal point

CCD - The CCD, which is a type of camera tube, is situated b/w the IR & television monitor. It converts light to electrons for viewing the monitor. - The electrostatic lenses, focal point, and output phosphor are image intensifier components.

________ is the concept that grids are MOST effective within certain source-to-image distances (SIDs). A. Convergent line B. Convergent point C. Radius D. Focal range

Focal range

Increased quantum mottle results in a decrease in: A. Spatial resolution. B. Scatter radiation production. C. Signal-to-noise ratio. D. Occupational exposure.

Signal-to-noise ratio

Compared with a low-ratio grid, a high-ratio grid: A. reduces image contrast. B. absorbs more scatter radiation. C. absorbs less primary radiation. D. reduces patient dose.

absorbs more scatter radiation - Increasing the grid ratio results in the absorption of more scatter radiation.

Mutual induction transformers need ________ to function. A. direct current B. alternating current C. milliamperage D. rectification

alternating current

A detector used for direct capture in digital radiography is made up of: A) cesium iodide + amorphous silicon photodiodes. B) amorphous selenium. C) CCD sensors. D) barium fluorohalide

amorphous selenium

An air-gap technique can be used in place of a grid in some instances because of: A) the inverse square law. B) anode heel effect C) a heterogeneous beam. D) beam divergence.

beam divergence. - the scatter radiation diverges past the image receptor.

Charge created in the amorphous silicon layer is collected at the: A. bias line. B. capacitor. C. scintillator. D. display.

capacitor

Assessing an image for visible differences between 2 selected areas of brightness means that the radiographer is evaluating the image's: A. receptor exposure. B. spatial resolution. C. distortion. D. contrast.

contrast Contrast - visible difference between 2 selected areas of brightness. Spatial resolution - sharpness of structural edges Receptor exposure - amount of radiation reaching the receptor.

Decreasing the kVp will _____ receptor exposure and _____ contrast A. decrease; decrease B. decrease; increase C. increase; decrease D. increase; increase

decrease ; increase - decreasing kVp increases contrast due to an increase in absorption & a decrease in scatter production - first, fewer photons are produced w/ lower kVp - second, more absorption takes place in the body, leaving fewer photons to make it to the receptor

In digital radiography flat-panel systems, spatial resolution is limited by the size of a: A. bit. B. byte. C. detector element. D. phosphor.

detector element.

The light emitted from the photostimulable phosphor plate during reading is the result of: A. electrons changing energy levels. B. atomic nuclei being excited by the laser. C. protons moving back into the nucleus. D. neutrons and electrons losing their charge.

electrons changing energy levels

In photostimulable phosphor plates, ________ is added to the barium fluorohalide crystals to serve as electron traps. A. europium B. silicon C. amorphous selenium D. cesium iodide

europium

Optically stimulated luminescence occurs when the: A. image is recorded on film using a laser printer. B. exposed PSP plate is scanned using a laser beam. C. photomultiplier tube amplifies the PSP output. D. analog-to-digital converter is mismatched with the computer

exposed PSP plate is scanned using a laser beam

In computed radiography, ________ is the identification of collimated edges to pull only useful data for scaling. A. look-up table analysis B. exposure rendition C. exposure field recognition D. histogram analysis

exposure field recognition

The output phosphor and charge-coupled device (CCD) are coupled using: A. fiber-optic cables or optical lenses. B. tube current. C. electrically conductive material. D. liquid crystal display (LCD) or plasma monitors.

fiber-optic cables or optical lenses

If an image displays low contrast, which of the following should the radiographer consider as a possible reason for the appearance? A. incorrect focal spot size selection B. too many photoelectric interactions C. field size that was too large D. use of improper receptor size

field size that was too large - As field size increases, the volume of irradiated tissue increases - when this happens more Compton interactions occur - the result is a decrease in image contrast.

All of the following are located in the secondary x-ray circuit EXCEPT for: rectifiers. the anode. filaments. stators.

filaments filaments are part of the filament circuit

The term comparing the amount of sensing area vs nonsensing area of a detector element (DEL) is: A. capacitance. B. shape factor. C. fill factor. D. charge storage.

fill factor

The ratio of a pixel's total size to its actual collection area is known as the: A. Nyquist frequency. B. pixel pitch. C. fill factor. D. charge modulation.

fill factor it includes the electronic connections responsible for conducting the signal away from the pixel

Which of the following factors affects subject contrast? OID grids mAs filtration

filtration - if filtration is added, subject contrast decreases - this is caused by an increase in the average beam energy - less absorption vs scatter occurs in the anatomical part - grids & OID affect image contrast. - the scatter has already been produced in the structure, but is removed or minimized before reaching the receptor.

The measurement of the half-value layer of the beam is an assessment of: A. filtration. B. linearity. C. reproducibility. D. beam congruity.

filtration Half-value layer is a measure of beam filtration

Total brightness gain for the image intensifier is calculated by: A. flux gain divided by minification gain. B. minification gain squared, multiplied by the flux gain. C. input phosphor diameter squared, divided by output phosphor diameter squared. D. flux gain multiplied by minification gain.

flux gain multiplied by minification gain

In fluoroscopy, if all other factors remain constant, an increase in mA: A. decreases image brightness. B. increases image brightness. C. increases image magnification. D. increases image minification.

increases image brightness - image brightness is determined by mA & time - as mA or time increase image brightness, patient dose also increase

Which of the following statements TRUE regarding sources-to-image distance (SID)? A. decreasing SID decreases Compton scatter B. decreasing SID decreases magnification. C. increasing SID increases receptor exposure D. increasing SID decreases distortion

increasing SID decreases distortion - Increasing SID will reduce distortion - specifically, the image will be less magnified

Which one of the following statements is TRUE about source-to-image distance (SID)? A. increasing SID decreases contrast B. increasing SID increases spatial resolution C. decreasing SID increases photoelectric absorption D. decreasing SID decreases receptor exposure

increasing SID increases spatial resolution - increasing SID results in the production of an image using a less divergent beam - the straighter traveling photons used to produce the image result in an increase in spatial resolution.

The glass envelope, tube window, and insulating oil account for what type of filtration? added wedge inherent trough

inherent

The air-gap technique uses a _____ source-to-image (SID) and a _____ object-to image distance (OID) A. short; short B. short; long C. long; short D. long; long

long;long - when using air-gap technique, OID is increased - SID also is increased to reduce part magnification that is caused by the increase in OID

All of the following are quality control (QC) tests for photostimulable imaging detectors EXCEPT FOR: A. uniformity. B. spatial resolution. C. luminance. D. erasure thoroughness

luminance - luminance is a QC test for image display monitors.

When fluoroscopy equipment is switched from fluoroscopic to radiographic mode, ________ increases. mA time kVp distance

mA - the fluoroscopy equipment normally operates at very low mA unless it is used in radiographic mode - radiographic mode provides a higher-quality image so mA is increased to reduce quantum mottle (or improve the signal-to-noise ratio in digital systems), time is decreased to avoid motion, and kVp is decreased to reduce scatter

All of the following affect spatial resolution EXCEPT: A) receptor angle B) focal spot size C) source-to-image distance (SID) D) mAs

mAs - receptor angle, focal spot size, & SID all affect the sharpness of structural edges on an image - mAs only affects the visibility of spatial resolution

Which of the following is TRUE regarding a fixed kVp chart? A. kVp is increased by 2 for every 1-cm increase in part thickness. B. kVp is increased by 15% for every 1-cm increase in part thickness. C. mAs is increased by a factor of 2 for every 4-cm increase in part thickness. D. mAs is increased by 15% for every 4-cm increase in part thickness.

mAs is increased by a factor of 2 for every 4-cm increase in part thickness - when using a fixed kVp chart, the optimal kVp for the anatomical part is selected & the mAs is varied according to part size - the general guideline is doubling or halving the mAs for approximately every 4-cm change in part thickness

The ________ explains why maintaining exposure relies on a change in time inversely proportional to a change in milliamperage (mA). A. mAs - intensity relationship B. mAs - distance compensation C. mAs grid conversion D. mAs reciprocity law

mAs reciprocity law

If all other factors remain constant in intensified fluoroscopy, the shift of the focal point toward the input phosphor: A. increases image brightness. B. increases the number of electrons created. C. improves image contrast. D. magnifies the image.

magnifies the image

Which of the following is used to minimize areas of brightness outside of the exposure field? A. masking B. smoothing C. equalization D. stitching

masking

Patient demographics and examination information are stored with a digital radiography image in the image's A. metadata. B. radiology information system (RIS). C. study ID. D. modality worklist.

metadata - demographic & examination info. are stored with every DICOM image as metadata

An increase in ________ will increase receptor exposure while maintaining image contrast. A) kilovoltage peak (kVp) B) source-to-image distance (SID) C) milliampere-seconds (mAs) D) object-to-image distance (OID)

milliampere-seconds (mAs) -increasing kVp increases receptor exposure, but decreases contrast - increasing SID decreases receptor exposure - increasing OID decreases receptor exposure & increases the contrast

The measurement of an imaging system's ability to demonstrate a specific image contrast for a specified spatial resolution is known as: A. dynamic range. B. quantum mottle. C. detective quantum efficiency. D. modulation transfer function.

modulation transfer function

Anodes consist of all the following materials EXCEPT FOR: tungsten. molybdenum. rhenium. nickle.

nickle

Spatial resolution of a computed radiography/direct radiography (CR/DR) image is predominantly controlled by the: A. matrix size. B. voxel size. C. pixel size. D. Hounsfield unit.

pixel size - spatial resolution of the image is predominately controlled by the pixel size

Which of the following does NOT describe the focusing cup? A. positively charged B. primarily composed of nickel C. prevents divergence of electron beam D. controls the spread of the space charge

positively charged - focusing cup is primarily nickel; nickel supplies a negative charge, which helps to condense the space charge and repel it away from the cathode assembly

Region of interest processing is a: A. point processing function. B. histogram. C. postprocessing function. D. look-up table.

postprocessing function - defining a region of interest (ROI) is a postprocessing function

The voltage between the anode and cathode is also called the: A. potential difference. B. space charge effect. C. mAs. D. Edison effect.

potential difference

Underexposure is MOST likely to result in which of the following? A. quantum mottle B. sampling error C. plate erasure failure D. detector saturation

quantum mottle

A series of unchanged exposures repeated sequentially is used to assess: A. timer accuracy. B. linearity. C. reproducibility. D. screen-film contact.

reproducibility - checking for consistent tube output with sequential exposures at the same setting assesses exposure reproducibility

The number of signal selections sent from a photodetector to the analog-to-digital converter is known as: A. pixel pitch. B. sampling pitch. C.field of view. D. sampling frequency.

sampling frequency

The ability of a system to record detail (expressed as the number of lan pairs per millimeter) is known as: A. spatial resolution. B. quality assurance. C. detail factor. D. finite factor.

spatial resolution