Which of the following is a deterministic radiation effect?

• A. Cancer
• B. Skin erythema
• C. Genetic mutations
• D. Leukemia

Answer: (B)

Deterministic effects have a threshold dose, and the severity of the effect increases as the dose goes up. Skin erythema is a classic example because you don’t see redness below a certain skin dose, but once you pass that threshold, redness appears and becomes more pronounced as the absorbed dose increases. This ties directly to damage in skin cells and microvasculature that manifests after exposure in a dose-dependent way.

In contrast, cancer, genetic mutations, and leukemia are stochastic effects. They don’t have a sharp dose at which they begin; instead, the probability of occurrence rises with dose, and the severity is not tied to the dose in the same deterministic manner.