ARRT Radiation Safety 3

Question 1

During a CT-guided biopsy procedure, which measure BEST reduces radiation exposure to the interventional CT technologist?

Accepted Answer

Using fluoroscopy-like CT intermittently and stepping back during exposures

Answer

Intermittent CT fluoroscopy combined with stepping away from the gantry during exposures significantly reduces occupational dose during interventional procedures.

Question 2

Which regulatory body sets the annual occupational effective dose limit of 50 mSv in the United States?

Accepted Answer

NRC and Agreement States

Answer

The Nuclear Regulatory Commission (NRC) and Agreement State regulations set the 50 mSv/year occupational effective dose limit (10 CFR 20).

Question 3

An automatic exposure control (AEC) system in CT adjusts which parameter in real time?

Accepted Answer

Tube current (mA) based on patient attenuation

Answer

CT AEC (tube current modulation) automatically adjusts mA based on patient size and attenuation to maintain consistent image quality at optimal dose.

Question 4

What is the recommended gonadal shielding practice for most routine CT examinations of the abdomen and pelvis?

Accepted Answer

Gonadal shielding is not routinely recommended because it can degrade image quality and obscure anatomy

Answer

Current ACR and AAPM guidance (2019) recommends against routine gonadal shielding in CT because it degrades image quality, increases dose, and gonads are rarely in the primary beam.

Question 5

Which scan parameter change will REDUCE patient dose while keeping all other factors constant?

Accepted Answer

Decreasing scan length from 40 cm to 30 cm

Answer

Reducing scan length directly reduces the total volume irradiated and therefore lowers DLP and patient dose.

(ARRT) American Registry of Radiologic Technologists Computed Tomography Certification Practice Test

(ARRT) American Registry of Radiologic Technologists Computed Tomography Certification Practice Test

ARRT Radiation Safety 3