Practice Test Geeks(CMD) Certified Medical Dosimetrist Practice Test
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CMD Clinical Oncology & Disease Sites Flashcards

6 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 6 CMD Clinical Oncology & Disease Sites flashcards as text

  1. For prostate cancer treated with definitive external beam radiotherapy, which structure is a primary organ at risk (OAR) that the dosimetrist must carefully contour and spare?

    Answer: Rectum

    The rectum is the most critical OAR for prostate EBRT; dose-volume constraints (e.g., V70Gy < 20%) are used to minimize the risk of late rectal toxicity.

  2. In breast cancer radiotherapy following lumpectomy, what is the target volume that typically receives the boost dose?

    Answer: Tumor bed (lumpectomy cavity)

    The tumor bed (surgical cavity) receives a boost dose after whole-breast irradiation to reduce local recurrence, particularly in younger patients with high-risk features.

  3. Which OAR dose constraint is most critical when treating head and neck cancers to prevent permanent xerostomia?

    Answer: Mean parotid dose < 26 Gy

    Keeping the mean parotid gland dose below approximately 26 Gy reduces the risk of long-term xerostomia, which is the most common debilitating late effect of head and neck RT.

  4. For lung cancer radiotherapy, what is a key pulmonary dose-volume constraint used to predict radiation pneumonitis risk?

    Answer: Mean lung dose (MLD) ≤ 20 Gy

    Mean lung dose ≤ 20 Gy and V20 ≤ 30–35% are standard constraints; exceeding these thresholds significantly increases the risk of symptomatic radiation pneumonitis.

  5. In whole-brain radiation therapy (WBRT), which structure should be considered for sparing to reduce neurocognitive decline?

    Answer: Hippocampus

    Hippocampal avoidance WBRT (HA-WBRT) spares the hippocampus (memory center) to reduce radiation-induced neurocognitive toxicity, as validated in the NRG CC001 trial.

  6. What is the standard clinical target volume (CTV) margin concept added around the gross tumor volume (GTV) in radiation therapy?

    Answer: Subclinical microscopic disease spread beyond the visible tumor

    The CTV margin around the GTV accounts for potential microscopic tumor extension not visible on imaging, based on known patterns of disease spread for each tumor site.