Deck 23: Digital Radiography

Question 1

A common feature between indirect and direct DR technology is

A)thin film technology (TFT).
B)a scintillation layer.
C)cassettes.
D)imaging plates (IP).

Answer 1

thin film technology (TFT).

Question 2

An eight-bit word is called a

A)byte.
B)RAM.
C)bit.
D)ROM.

Answer 2

byte.

Question 3

Computed radiography is also referred to as

A)PSP technology.
B)flat panel technology.
C)indirect DR.
D)direct DR.

Answer 3

PSP technology.

Question 4

If the digital FOV is 1024 and the display matrix is 256, the pixel size would be

A)4
B)128
C)768
D)262,144

Question 5

CR systems acquire clinical information by

A)laser scanning a PSP plate.
B)gathering light from a scintillator.
C)direct digital transformation of x-ray photon energy to a selenium plate.
D)capturing light from a charged couple device (CCD).

Question 6

A matrix of size 2048x1536 would have _______ pixels.

A)512
B)3584
C)3,145,728
D)none of the above

Question 7

Computerized digital images consist of a ________ of picture elements, each with a video display value or gray shade.

A)row
B)matrix
C)column
D)pixel

Question 8

The window width controls

A)image density.
B)image contrast.
C)speed.
D)depth.

Question 9

When the main power to the computer is turned off, ____ is erased.

A)RAD
B)RAM
C)REM
D)ROM

Question 10

Each binary number is called a

A)pixel.
B)bit.
C)byte.
D)voxel.

Question 11

Which computer device does not store memory?

A)floppy disc
B)diskette
C)optical disk
D)mouse

Question 12

The window level controls

A)image density.
B)image contrast.
C)speed.
D)brightness.

Question 13

Digital radiography (DR) is characterized by

A)the electronification of data scanned from a film-based media.
B)the use of reusable receptors.
C)the application of analog counting techniques.
D)the processing of the receptor data using dry chemistries.

Question 14

Each pixel in a digital display matrix is located according to its

A)electronic address.
B)voxel position.
C)DICOM address.
D)FOV.

Question 15

Window width changes are sometimes called

A)gray scale expansion.
B)enhancing visibility of detail.
C)gray scale compression.
D)all of the above

Question 16

When the main power to the computer is turned off, ____ is maintained.

A)RAD
B)REM
C)ROM
D)RAM

Question 17

Computers operate using a ____ language.

A)monosyllabic source language
B)binary machine
C)logarithmic machine
D)26-letter symbolic

Question 18

In digital imaging, the limiting factor in spatial resolution is the

A)pixel depth.
B)pixel size.
C)bit depth.
D)pixel pitch.

Question 19

Indirect DR uses ________ as the detector material.

A)calcium tungstate
B)amorphous selenium
C)amorphous silicon
D)CCD

Question 20

Resolution is controlled by ____ size.

A)bit
B)pixel
C)matrix
D)byte

Question 21

When changing exposure technique from 9 mAs to 18 mAs using computed radiography, the radiographer should expect

A)an increase in S number from 350 to 475.
B)an EI number increase from 1500 to 1800.
C)a visible change in radiographic image density.
D)all of the above

Question 22

In digital image processing, an overexposed or underexposed image can be modified to achieve an acceptable "look" through a histogram analysis.This is the result of the digital processing technique of

A)histogram stretching.
B)histogram modification.
C)rescaling.
D)all of the above

Question 23

The relationship between digital image resolution

A)is direct with matrix size.
B)is indirect with pixel size.
C)is direct with pixel bit depth.
D)both a and b

Question 24

Of the choices below, the best S:N ratio is

A)10:1.
B)100:1.
C)500:1.
D)1000:1.

Question 25

All of the following are true of local area processing EXCEPT:

A)It relies on the application of kernels to pixels.
B)Kernels are ultimately applied to the entire pixel data set.
C)Spatial filtering is an example of local area processing.
D)Electronic magnification of the image is an example of local area processing.

Question 26

Which of the choices below would produce the highest spatial frequency and contrast?

A)gall bladder
B)contrast filled urinary bladder
C)3 mm renal calculi (stone)
D)contrast-filled appendix

Question 27

Of the many types of digital image procedures performed in a contemporary medical imaging department, the largest file sizes are typically generated by

A)digital mammography.
B)MRI.
C)computed radiography.
D)digital fluoroscopy.

Question 28

The purpose of a LUT is to

A)determine the exposure index.
B)create the histogram.
C)apply a predetermined scale of contrast to the digital data set.
D)perform geometric processing in order to reorient the image on display.

Question 29

Noise on a digital image is the summation of inherent electron system noise and quantum mottle noise.Of these two, the radiographer can improve the noise on an image by

A)decreasing the exposure intensity of the x-ray beam.
B)increasing the exposure technique.
C)turning off any electronic devices during exposures.
D)all of the above

Question 30

Of the choices below, the greatest ALARA violation would be

A)using AEC and increasing the SID to 48".
B)repeating an image with an S number of 210 because of exposure technique.
C)using 90 kVp and a 10:1 radiographic grid.
D)electronically magnifying the image on the monitor and sending it off to be archived.

Question 31

The response to radiation exposure with a digital receptor is

A)non-linear.
B)logarithmic.
C)linear with a threshold.
D)linear.

Question 32

When matrix size is increased and pixel size goes down,

A)spatial resolution decreases.
B)spatial resolution increases.
C)contrast increases.
D)both a and c

Question 33

In digital image processing, the digital data set is arranged into a histograph distribution in order to determine the

A)display matrix.
B)exposure index.
C)values of interest (VOI).
D)both b and c

Question 34

When the quality of a digital detector is inspected for purchase, the preferred detector for purchase would have a

A)DQE of 65% and MTF of 0.55.
B)DQE of 40% and MTF of 0.80.
C)DQE of 68% and MTF of 0.80.
D)DQE of 55% and MTF of 0.35.

Question 35

An S value of 200 represents a/an

A)exposure to the IP of 1 mR.
B)window level of brightness.
C)suboptimum exposure to the receptor.
D)S:N ratio.

Question 36

Grossly overexposed digital images will demonstrate

A)grainy images.
B)a loss of contrast.
C)higher contrast.
D)noisy images.

Question 37

All of the following are related except one.Select the choice that is NOT RELATED to the others.

A)local processing
B)manual processing
C)point processing
D)geometric processing

Question 38

The deviation index (DI)

A)compares entrance dose to the detector to a reference industry-standard target dose.
B)compares entrance dose to the patient to a reference industry-standard target dose.
C)compares exit dose to the detector to a reference industry-standard target dose.
D)compares DQE and MTF with a reference value.

Question 39

If the radiographer applied an ankle LUT to a chest radiograph data set, the image would demonstrate

A)high contrast.
B)low contrast.
C)very high resolution.
D)low resolution.

Question 40

A pixel that has an 8-bit depth displays _______ shades of gray.

A)126
B)256
C)512
D)1024

Question 41

In CR technology, preprocessing of data includes

A)histogram analysis.
B)gray scale analysis.
C)exposure data recognition (EDR).
D)all of the above

Question 42

An x-ray exposure taken at 80 kVp has an average energy of

A)24 keV.
B)35 keV.
C)60 keV.
D)80 keV.

Question 43

All of the following impact digital image spatial resolution EXCEPT

A)pixel pitch.
B)bits/pixel.
C)DEL dimension.
D)sampling frequency.

Question 44

When using a Fuji CR system in the fixed-mode of operation,

A)exposure techniques are variable and adjustable by the computer to adjust density and contrast.
B)the system will not correct for exposure inadequacies and adjust for density problems.
C)your exposure techniques must be accurate, similar to film/screen technology.
D)both b and c

Question 45

In digital image technology, once the image data is sent to PACS

A)the data can be reprocessed by the radiologist.
B)the data is fixed and not able to be reprocessed.
C)the file size is then calculated and compressed.
D)it is converted to raw data for archival.

Question 46

When using CR technology, it is important to remember that

A)the IP is extrasensitive to exposure after the initial x-ray exposure.
B)the IP will lose about 25% of its signal in 8 hours if not processed.
C)the IP is very sensitive to scatter, making grids very important.
D)all of the above

Question 47

All of the following are true of the Moire effect EXCEPT:

A)It results from a conflict in spatial frequencies between the grid frequency and laser scanning frequency.
B)It produces useless diagonal dark lines across the finished image.
C)It is most likely to occur with DR technology, particularly amorphous selenium.
D)It is eliminated with ultra-high grid frequencies 178-200 lpi.

Question 48

All of the following are true of pixel pitch EXCEPT:

A)It is defined as the distance between pixels.
B)It is not related to spatial resolution.
C)It is determined by the size of the DEL in DR systems.
D)It is measured from the center-to-center of the pixels.

Question 49

The size of a digital file size is determined by the

A)bit depth.
B)pixel size.
C)matrix.
D)all of the above

Question 50

In the technology of CR, the latent image is actually

A)sensitivity specks in the barium fluorohalide.
B)free electrons in the amorphous silicon.
C)electron "holes" in Europium.
D)the light from the phosphor following laser excitation of the reader assembly.