Image Production & Processing Flashcards

In digital radiography, what does the exposure index (EI) primarily indicate?

Answer: The amount of radiation that reached the detector

The exposure index is a measure of the radiation exposure reaching the digital detector, used to assess whether the detector was properly exposed.

Which artifact in computed radiography (CR) appears as a ghost image from a previous exposure due to incomplete erasure?

Answer: Lag artifact (ghosting)

Lag (ghosting) occurs when residual signal from a previous exposure is not fully erased from the PSP plate before the next exposure.

What is the primary advantage of direct digital radiography (DR) over computed radiography (CR)?

Answer: Immediate image availability without plate handling

DR panels provide immediate image display because there is no separate plate processing step, improving workflow efficiency.

In digital imaging, which term describes the range of exposure values over which the detector can produce a diagnostic image?

Answer: Dynamic range

Dynamic range refers to the range of exposure values (from very low to very high) that a digital detector can accurately capture and display.

What happens to image noise (quantum mottle) when mAs is decreased in digital radiography?

Answer: Noise increases because fewer photons form the image

Reducing mAs decreases the number of photons reaching the detector, resulting in a noisier (more mottled) image due to quantum noise.

Which factor primarily determines the spatial resolution of a digital detector system?

Answer: Pixel size (detector element size)

Spatial resolution in digital radiography is primarily limited by the size of the detector elements (pixels) — smaller pixels yield higher resolution.