Question

A patient comes into the hospital because she is worried about possible exposure to radiation. The doctors determine that the patient has 60 rem of exposure. What is her risk of cancer?
High because her exposure is less than 100 rem.
High because her exposure is greater than 50 rem.

Answer 1

The second statement is correct: "High because her exposure is greater than 50 rem."

Explanation and numbers:
- 60 rem = 0.6 Sv (1 rem = 0.01 Sv).
- Using the commonly used linear no‑threshold estimate (~5% increased lifetime cancer risk per Sv), 0.6 Sv ≈ 0.6 × 5% ≈ a 3% absolute increase in lifetime cancer risk above baseline. (Baseline lifetime cancer risk in many populations is ~30–40%, so this would raise it by roughly 3 percentage points.)
- 60 rem is below commonly cited thresholds for deterministic acute radiation sickness (ARS) symptoms (around ~100 rem/1 Sv and higher), so significant acute radiation illness is unlikely, but the exposure is large enough to be clinically important and to warrant follow‑up.

Recommended actions (brief):
- Document dose and timing, assess for contamination.
- Baseline and serial blood counts (lymphocytes), symptom monitoring.
- Consider expert consultation (radiation safety officer, radiation oncology/hematology) and biodosimetry if precise dose assessment is needed.
- Provide counseling about the modestly increased cancer risk and any pregnancy concerns if applicable.