Ch. 23 - Digital Equipment (Exp I & II)

Question 1

Digital radiography (DR) is characterized by…

Answer 1

The use of reusable receptors

Question 2

Computers operate using a ______ language.

Answer 2

Binary machine

Question 3

Each binary number is called a…

Answer 3

Bit

Question 4

An eight-bit word is called a…

Answer 4

Byte

Question 5

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

Answer 5

RAM

Question 6

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

Answer 6

ROM

Question 7

Computed radiography is also referred to as…

Answer 7

PSP technology

Question 8

Indirect DR uses _______ as the detector material.

Answer 8

Amorphous silicon

Question 9

CR systems acquire clinical information by…

Answer 9

Laser scanning a PSP plate

Question 10

The window width controls…

Answer 10

Image contrast

Question 11

The window level controls…

Answer 11

Brightness

Question 12

Window width changes are sometimes called…

Answer 12

• Gray scale expansion
• Enhancing visibility of detail
• Gray scale compression

Question 13

Resolution is controlled by ____ size.

Answer 13

Pixel

Question 14

A common feature between indirect and direct DR technology is…

Answer 14

Thin film technology (TFT)

Question 15

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

Answer 15

Matrix

Question 16

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

Answer 16

Electronic address

Question 17

In digital imagine, the limiting factor in spatial resolution is the…

Answer 17

Pixel size

Question 18

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

Answer 18

256

Question 19

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

a. ) Gall bladder
b. ) Contrast filled urinary bladder
c. ) 3mm renal calculi (stone)
d. ) Contrast-filled appendix

Answer 19

c.) 3mm renal calculi (stone)

Question 20

Which of the following is not related to the others?

a. ) Local processing
b. ) Manual processing
c. ) Point processing
d. ) Geometric processing

Answer 20

b.) Manual processing

Question 21

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 ad c

Answer 21

d.) Both b and c

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

Answer 22

d.) All of the above

Question 23

The purpose of LUT is to…

Answer 23

Apply a predetermined scale of contrast to the digital data set.

Question 24

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

Answer 24

High contrast

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

Answer 25

d.) Electronic magnification of the image is an example of local area processing

Question 26

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

Answer 26

d.) Both a and b

Question 27

When matrix size is increased ad pixel size goes down,

Answer 27

Spatial resolution increases

Question 28

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

Answer 28

Digital fluoroscopy

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...

Answer 29

Increasing the exposure technique.

Question 30

Of the following, the best S:N ratio is a. ) 10:1 b. ) 100:1 c. ) 500:1 d. ) 1,000:1

Answer 30

d.) 1,000:1

Question 31

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

Answer 31

c.) DQE of 68% and MTF of 0.80

Question 32

The deviation index (DI)...

Answer 32

Compares entrance dose to the detector to a reference industry-standard target dose.

Question 33

An S value of 200 represents...

Answer 33

An exposure to the IP of 1 mR

Question 34

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

Answer 34

An EI number increase from 1500 to 1800.

Question 35

The response to radiation exposure with a digital receptor is...

Answer 35

Linear

Question 36

Grossly overexposed digital images will demonstrate...

Answer 36

A loss of contrast

Question 37

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

Answer 37

d.) All of the above

Question 38

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

Answer 38

35 keV

Question 39

In the technology of CR, the latent image is actually...

Answer 39

Electron "holes" in Europium

Question 40

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. ) Is is determined by the size of the DEL in DR systems d. ) It is measured from the center-to-center of the pixels

Answer 40

b.) It is not related to spatial resolution

Question 41

All of the following impact digital image spatial resolution EXCEPT: a. ) Pixel pitch b. ) Bits/pixel c. ) DEL dimension d. ) Sampling frequency

Answer 41

b.) Bits/pixel

Question 42

The size of the digital file size is determined by the: a. ) Bit depth b. ) Pixel size c. ) Matrix d. ) All of the above

Answer 42

d.) All of the above

Question 43

In CR technology, pre-processing of data includes: a. ) Histogram analysis b. ) Gray scale analysis c. ) Exposure data recognition (EDR) d. ) All of the above

Answer 43

d.) All of the above

Question 44

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

Answer 44

The data is fixed and not able to be reprocessed.

Question 45

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

Answer 45

d.) Both b and c

Question 46

All of the following are TRUE of 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

Answer 46

c.) It is most likely to occur with DR technology, particularly amorphous selenium