Computed Tomography Test CT Radiation Safety and Dosimetry 3

Question 1

Which CT technique reduces dose by acquiring fewer projections and reconstructing with iterative algorithms?

Accepted Answer

Low-dose CT with iterative reconstruction

Answer

Low-dose CT combined with iterative reconstruction algorithms can reduce dose by up to 80% compared to traditional filtered back projection while maintaining diagnostic quality.

Question 2

The term 'Z-axis dose profile' in CT refers to dose distribution along which direction?

Accepted Answer

Patient cranio-caudal (head-to-foot) axis

Answer

The Z-axis is the cranio-caudal axis along which the patient moves through the gantry, and the dose profile describes radiation distribution along this direction.

Question 3

What effect does increasing CT tube voltage (kVp) have on patient dose?

Accepted Answer

Increases dose due to higher photon energy and greater beam penetration

Answer

Higher kVp increases photon energy and quantity (via space charge effect), generally increasing patient dose, though it may allow mAs reduction in large patients.

Question 4

In CT fluoroscopy-guided procedures, which group is at highest risk for radiation injury?

Accepted Answer

The interventionalist's hands if placed in the beam

Answer

CT fluoroscopy uses continuous X-ray exposure, and the interventionalist's hands can receive very high doses if placed near or in the primary beam.

Question 5

Which regulatory body in the United States sets occupational radiation dose limits for CT technologists?

Accepted Answer

Nuclear Regulatory Commission (NRC)

Answer

The NRC sets the annual occupational whole-body dose limit of 50 mSv (5 rem) for radiation workers in the US, including CT technologists.

Computed Tomography Test Practice Test

Computed Tomography Test Practice Test

Computed Tomography Test CT Radiation Safety and Dosimetry 3