Radiography Exam ARRT Radiography 5

Question 1

The specific absorption of x-ray photons by the photoelectric effect is MOST likely to occur when:

Accepted Answer

Photon energy is slightly greater than the binding energy of the electron

Answer

Photoelectric absorption is most probable when the incident photon energy just exceeds the binding energy of the inner-shell electron.

Question 2

Which modality uses gradient magnetic fields superimposed on the static magnetic field to spatially encode the MR signal?

Accepted Answer

Gradient coils

Answer

Gradient coils create small, controlled variations in the magnetic field used for slice selection, frequency encoding, and phase encoding in MRI.

Question 3

The Bucky factor (grid factor) represents:

Accepted Answer

How much more mAs is required when using a grid compared to non-grid technique

Answer

The Bucky factor indicates the exposure increase needed when adding a grid; a factor of 4 means 4× more mAs is required.

Question 4

For the AP axial projection of the coccyx, the central ray is angled:

Accepted Answer

30° caudad

Answer

A 10–30° caudad angle is directed to 2 inches superior to the pubic symphysis to project the coccyx free of superimposition.

Question 5

Which of the following is a late (deterministic) effect of high-dose radiation exposure?

Accepted Answer

Cataracts of the lens

Answer

Cataracts are a deterministic (non-stochastic) effect with a threshold dose; they occur at high exposures to the ocular lens.

Radiography Exam Practice Test