Which unit is used to express radiation absorbed dose?

The unit used to express radiation absorbed dose is the Gray (Gy). One Gray is defined as the absorption of one joule of radiation energy by one kilogram of matter. In the context of absorbed dose, it measures the amount of energy deposited by ionizing radiation in a given mass of material, which is essential for understanding the effects of that radiation on biological tissues.

While the Rad is also a unit for measuring absorbed dose, where one Rad is equivalent to 0.01 Gray, it is now largely considered outdated and has been largely replaced by the Gray in most standards and regulations. This transition helps unify measurements globally under the SI (International System of Units).

The Rem and Curie are not appropriate for absorbed dose; rather, Rem is used to express dose equivalent, which considers the biological effect of radiation, while the Curie measures the radioactivity of a material, specifically the quantity of radioactive decay.