ARRT Digital Imaging and Exposure Factors

Question 1

In digital radiography, which exposure indicator value signifies optimal exposure on most current CR/DR systems?

Accepted Answer

EI of 300 (system-dependent target near 300)

Answer

EI of 50

Answer

EI of 1200

Answer

EI of 25

Question 2

What does a deviation index (DI) of 0 indicate in a digital imaging system?

Accepted Answer

Exposure is exactly at the target exposure index

Answer

Severe underexposure

Answer

Severe overexposure

Answer

Equipment malfunction

Question 3

Which primary exposure factor has the greatest effect on subject contrast in digital radiography?

Accepted Answer

kVp (kilovoltage peak)

Answer

mA (milliamperage)

Answer

Exposure time

Answer

Source-to-image distance

Question 4

In computed radiography (CR), what component captures the latent image?

Accepted Answer

Photostimulable phosphor (PSP) imaging plate

Answer

Flat-panel detector with amorphous silicon

Answer

Charge-coupled device (CCD)

Answer

Direct conversion selenium detector

Question 5

What is the primary advantage of direct conversion flat-panel detectors (FPD) over indirect conversion FPDs?

Accepted Answer

Superior spatial resolution due to no light-spreading step

Answer

Lower cost

Answer

Higher radiation dose to patient

Answer

Faster read time only

Question 6

Which artifact in digital radiography results from a CR imaging plate not being completely erased before reuse?

Accepted Answer

Ghost image (ghosting)

Answer

Moiré artifact

Answer

Grid cutoff

Answer

Quantum mottle