What factor is crucial in determining the external dose from radiation?

The determination of external dose from radiation is heavily influenced by time spent in the radiation field. The longer an individual is exposed to a source of radiation, the greater their dose will be. This is based on the principle that radiation interacts with tissues over time, and the total dose received is the product of both the intensity of the radiation and the duration of exposure.

In practical terms, if a person spends more time near a radiation source without any intervening protective measures, they will accumulate a higher dose of radiation compared to someone who limits their exposure. This highlights the importance of managing exposure time as a critical factor in radiation safety protocols.

While factors such as the type of radiation emitted, distance from the radiation source, and shielding effectiveness are all significant in assessing radiation risk and dose, they do not directly account for the time-related accumulation of dose. Safe practices in radiation areas often include minimizing time spent in those areas as a simple yet effective measure to reduce exposure and ensure safety.