What unit is commonly used to measure radiation exposure?

The most appropriate unit for measuring radiation exposure is the Gray (Gy). The Gray is specifically defined as the absorption of one joule of radiation energy by one kilogram of matter. This unit is directly correlated to the amount of energy deposited by ionizing radiation in a given mass, which is crucial for assessing the biological effect of radiation on tissues.

While Sieverts are also a unit related to radiation, they are used primarily to account for the biological effects and tissue weighting factors associated with different types of radiation, rather than measuring exposure directly. Rads, which is an older unit, provide a measure of absorbed radiation, similar to the Gray but are less commonly used in contemporary contexts. Curie is a unit that measures radioactive decay and activity, rather than the direct effects or exposure of that radiation on human tissues.

Hence, the Gray is the most suitable choice for quantifying radiation exposure in a manner that reflects the impact of radiation on biological systems.