Which of the following is NOT a characteristic of deterministic effects?

Deterministic effects are biological effects of radiation that occur after receiving a dose above a certain threshold. One of the key characteristics of these effects is that they have a known threshold dose. This means that there must be a minimum amount of radiation exposure before the effects are observed, and once this threshold is exceeded, the likelihood and severity of the effects increase as the dose increases. This relationship is both predictable and consistent.

Therefore, the assertion that deterministic effects occur randomly is not accurate, as they do not happen without a certain level of exposure. Instead, they follow a specific dose-response pattern where the severity aligns with the dose received. This is why the assertion regarding randomness is the characteristic that does not apply to deterministic effects.