What term describes the additive biologic effect from repeated exposure to radiation?

• A. Cumulative effect
• B. Acute effect
• C. Deterministic effect
• D. Stochastic effect

Answer: (A)

Repeated radiation exposure adds to the total biological burden; the effects from each exposure accumulate over time. This is why the term cumulative effect is used—it describes how the sum of doses received across multiple events drives greater overall damage and risk, especially for late outcomes like cancer. Each small exposure contributes to the total, so the risk increases with the total dose, even if individual doses are below levels that cause immediate harm.

An acute effect, in contrast, comes from a single high dose delivered in a short period. Deterministic effects have a threshold and become more severe as dose rises, not simply from accumulating exposures. Stochastic effects are probabilistic, with risk increasing with dose but without a defined threshold; they describe the chance of occurrence rather than a direct, additive dose-response.