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Radiation Safety Flashcards

7 cards from real ARRT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Radiation Safety flashcards as text

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

    Answer: Using fluoroscopy-like CT intermittently and stepping back during exposures

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

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

    Answer: NRC and Agreement States

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

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

    Answer: Tube current (mA) based on patient attenuation

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

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

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

    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.

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

    Answer: Decreasing scan length from 40 cm to 30 cm

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

  6. In CT, iterative reconstruction (IR) algorithms primarily allow dose reduction by:

    Answer: Producing diagnostic-quality images at lower mAs settings than filtered back projection

    Iterative reconstruction models image noise mathematically, allowing lower mAs protocols to produce acceptable image quality compared to filtered back projection.

  7. A pregnant patient requires urgent abdominal CT. What is the approximate threshold fetal dose below which deterministic effects (e.g., malformations) are considered negligible?

    Answer: 50 mGy

    Below approximately 50 mGy, deterministic effects such as malformations or growth retardation are not expected; however, stochastic risk remains and dose should be minimized.