What does 'protraction' refer to in radiation exposure?

Protraction in the context of radiation exposure refers to spreading out a radiation dose over a longer duration. This method can lead to less acute biological effects compared to delivering the same dose over a shorter, concentrated period. The rationale is that when radiation exposure is protracted, the biological systems have more time to repair damage between exposures, potentially leading to reduced overall harm and increased cellular repair processes.

In contrast, concentrating a dose in a short period can lead to higher immediate damage and greater biological effects, as tissues may not have adequate time to recover. Reducing the total dose or enhancing biological effects are different concepts and do not directly relate to the definition of protraction in radiation biology. Thus, understanding protraction focuses on how the timing and distribution of radiation exposure impact biological response.