Practice Test Geeks(CMD) Certified Medical Dosimetrist Practice Test
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Quality Assurance & Control Flashcards

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

Read the first 7 Quality Assurance & Control flashcards as text

  1. A medical dosimetrist is performing chart rounds and notices a patient received 210 cGy instead of 200 cGy per fraction for the first three fractions. What is the dosimetric significance of this error?

    Answer: The cumulative overdose of 30 cGy may exceed normal tissue tolerance and requires physician review

    A 5% per-fraction overdose resulting in 30 cGy cumulative error requires physician review to assess biological impact on tumor and normal tissue tolerances.

  2. Which of the following best describes the role of independent monitor unit verification in radiation therapy QA?

    Answer: Confirming that the planned MU are correct using a second, independent calculation method

    Independent MU verification uses a separate algorithm or manual calculation to confirm the primary TPS-calculated monitor units, serving as a check against computational errors.

  3. During patient-specific IMRT QA, a significant disagreement is found between measured and calculated dose in one region of the plan. Which investigation step should occur FIRST?

    Answer: Review the treatment plan for calculation errors and verify detector positioning

    The first step is to review the treatment plan for errors and confirm detector setup before repeating the measurement, to avoid repeating an erroneous procedure.

  4. What is the AAPM-recommended frequency for performing a full mechanical and radiation isocenter coincidence test (e.g., Winston-Lutz) on a dedicated SRS/SBRT linac per TG-142?

    Answer: Monthly

    TG-142 recommends monthly isocenter coincidence testing for SRS/SBRT-capable linacs, with tighter tolerances (1 mm) compared to standard linacs.

  5. A dosimetrist is validating a new treatment planning system for clinical use. Which document provides the framework for TPS commissioning and acceptance testing?

    Answer: AAPM TG-53

    AAPM TG-53 provides comprehensive guidelines for quality assurance of radiation therapy treatment planning systems, covering commissioning, acceptance testing, and ongoing QA.

  6. When using film dosimetry for IMRT QA, radiochromic film (EBT3) is preferred over radiographic film primarily because:

    Answer: Radiochromic film does not require dark room processing and has lower energy dependence

    EBT3 radiochromic film self-develops without chemical processing and exhibits lower energy dependence compared to radiographic film, making it more practical and accurate for megavoltage dosimetry.

  7. A patient's treatment course involves daily IGRT with cone-beam CT (CBCT). Which QA test ensures the CBCT imaging isocenter is coincident with the treatment isocenter?

    Answer: Winston-Lutz test adapted for CBCT guidance

    A Winston-Lutz–style test adapted for CBCT verifies that the imaging isocenter aligns with the treatment radiation isocenter, ensuring accurate patient setup corrections.