Practice Test Geeks(ARRT) American Registry of Radiologic Technologists Computed Tomography Certification Practice Test
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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. Which phantom is used to measure CTDI100 according to the standard FDA/IEC protocol?

    Answer: A 16 cm diameter PMMA phantom for head and a 32 cm phantom for body

    The FDA/IEC protocol uses a 16 cm PMMA phantom for head measurements and a 32 cm phantom for body measurements to derive CTDI100.

  2. A CT technologist notices the dose reference level (DRL) for a routine chest CT is being routinely exceeded. The BEST first step is to:

    Answer: Review and optimize the scan protocol to determine if dose can be reduced without compromising diagnostic quality

    DRLs serve as benchmarks; exceeding them triggers a protocol review to identify optimization opportunities while preserving diagnostic image quality.

  3. What is the primary radiation hazard associated with CT compared to conventional radiography?

    Answer: Significantly greater patient dose due to multiple rotational acquisitions and extended scan volumes

    CT delivers substantially higher patient doses than conventional radiography because it involves multiple rotational X-ray acquisitions covering large anatomical volumes.

  4. Which factor does NOT directly influence the CTDI_vol value displayed on the CT console?

    Answer: Reconstruction kernel (filter)

    Reconstruction kernel is a post-processing parameter applied after data acquisition and does not change the radiation output; CTDI_vol reflects acquisition parameters only.

  5. A technologist is scanning a patient with metal hip implants. To reduce dose while managing metal artifact, which approach is MOST appropriate?

    Answer: Use metal artifact reduction (MAR) software at standard dose rather than routinely increasing mAs

    Metal artifact reduction software effectively manages implant artifacts at standard dose; routinely increasing mAs adds unnecessary patient dose without eliminating artifacts.

  6. Under NRC regulations, which of the following events involving a CT scanner MUST be reported as a medical event?

    Answer: Delivery of a dose differing from the prescribed dose by more than 50 mSv effective dose or 500 mSv to an organ when not due to patient condition

    A medical event under 10 CFR 35.3045 requires reporting when the wrong patient receives a dose, or dose differs from the prescribed dose by >50 mSv effective dose or >500 mSv to any organ.

  7. The inverse square law states that radiation intensity is related to distance by which relationship?

    Answer: Intensity is inversely proportional to the square of the distance

    The inverse square law: I ∝ 1/d², meaning doubling the distance from the source reduces intensity to one-quarter of its original value.