RADIOLOGIC TECHNOLOGY – DIGITAL RADIOGRAPHY (DR) PRACTICE
TEST (140 QUESTIONS) – MOST TESTED QUESTIONS &
COMPREHENSIVE EXAM REVIEW MATERIAL
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):
a. 1
b. 3
c. 5
d. 6 - ANSWER****c
Whenever there is an insufficient sampling rate for a high-frequency digital image, ______
artifacts may be created:
a. pixel drop-out
b. halo
c. reticulation
d. aliasing - ANSWER****d
When compared to CR, which of the following is not a disadvantage of DR:
a. Tendency to use the bucky grid for distal extremities
b. Less flexibility in positioning
c. Bulky and cumbersome receptor plates
d. Less consistency in image quality - ANSWER****d
,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:
a. computed tomography
b. conventional tomography
c. linear positron emission tomography
d. scanned projection radiography
e. direct-scan radiography - ANSWER****d
For DR, the size of the individual detector elements (dexels) currently used is closest to:
a. 1 cm
b. 1 mm
c. 100 microns (1/10th mm)
d. 1 micron (1/1000th mm)
e. 1 nanometer - ANSWER****c
The Nyquist criterion states that to prevent aliasing, the sampling rate must be _____ the spatial
frequency of the image:
a. Equal to
b. At least twice
c. One-half
d. Four times - ANSWER****b
Which of the following would be caused by fluctuations in the electrical current passing through
the image acquisition system or digital processing system:
a. Electronic aliasing
b. Grid aliasing
,c. Electronic mottle
d. Material mottle - ANSWER****c
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
d. all of the above
e. b & c only - ANSWER****d
The development of which of the following enabled DR systems to use a flat-shaped receptor
plate:
a. thin-film transistors (TFTs)
b. electronic capacitors
c. photostimulable phosphor plates
d. the photomultiplier tube
e. flat light guides - ANSWER****a
Which of the following has the highest DQE, at 77%:
a. conventional screens and film
b. CR phosphor plates
c. direct-conversion DR plates
d. indirect-conversion DR plates - ANSWER****d
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?
, a. the pixel
b. the dexel (or del)
c. the voxel
d. the rexel
e. the dynode - ANSWER****b
To a computer expert, a true pixel is a numerical value assigned to a(n):
a. small square area in the image
b. small circular area in the image
c. small square detector surface
d. small circular detector surface
e. point with no dimensions - ANSWER****e
In a DR image receptor, most of the square area of each dexel is dedicated to what portion of
the detector element:
a. the thin-film transistor
b. the semiconductor layer
c. the capacitor
d. the gate lines - ANSWER****b
For CR, the most common source of image artifacts is the:
a. patient
b. phosphor plate
c. reader (processor)
d. computer - ANSWER****b
TEST (140 QUESTIONS) – MOST TESTED QUESTIONS &
COMPREHENSIVE EXAM REVIEW MATERIAL
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):
a. 1
b. 3
c. 5
d. 6 - ANSWER****c
Whenever there is an insufficient sampling rate for a high-frequency digital image, ______
artifacts may be created:
a. pixel drop-out
b. halo
c. reticulation
d. aliasing - ANSWER****d
When compared to CR, which of the following is not a disadvantage of DR:
a. Tendency to use the bucky grid for distal extremities
b. Less flexibility in positioning
c. Bulky and cumbersome receptor plates
d. Less consistency in image quality - ANSWER****d
,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:
a. computed tomography
b. conventional tomography
c. linear positron emission tomography
d. scanned projection radiography
e. direct-scan radiography - ANSWER****d
For DR, the size of the individual detector elements (dexels) currently used is closest to:
a. 1 cm
b. 1 mm
c. 100 microns (1/10th mm)
d. 1 micron (1/1000th mm)
e. 1 nanometer - ANSWER****c
The Nyquist criterion states that to prevent aliasing, the sampling rate must be _____ the spatial
frequency of the image:
a. Equal to
b. At least twice
c. One-half
d. Four times - ANSWER****b
Which of the following would be caused by fluctuations in the electrical current passing through
the image acquisition system or digital processing system:
a. Electronic aliasing
b. Grid aliasing
,c. Electronic mottle
d. Material mottle - ANSWER****c
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
d. all of the above
e. b & c only - ANSWER****d
The development of which of the following enabled DR systems to use a flat-shaped receptor
plate:
a. thin-film transistors (TFTs)
b. electronic capacitors
c. photostimulable phosphor plates
d. the photomultiplier tube
e. flat light guides - ANSWER****a
Which of the following has the highest DQE, at 77%:
a. conventional screens and film
b. CR phosphor plates
c. direct-conversion DR plates
d. indirect-conversion DR plates - ANSWER****d
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?
, a. the pixel
b. the dexel (or del)
c. the voxel
d. the rexel
e. the dynode - ANSWER****b
To a computer expert, a true pixel is a numerical value assigned to a(n):
a. small square area in the image
b. small circular area in the image
c. small square detector surface
d. small circular detector surface
e. point with no dimensions - ANSWER****e
In a DR image receptor, most of the square area of each dexel is dedicated to what portion of
the detector element:
a. the thin-film transistor
b. the semiconductor layer
c. the capacitor
d. the gate lines - ANSWER****b
For CR, the most common source of image artifacts is the:
a. patient
b. phosphor plate
c. reader (processor)
d. computer - ANSWER****b
