Absorbed dose

Absorbed dose is a dose quantity which represents the specific energy (energy per unit mass) deposited by ionizing radiation in living matter. Absorbed dose is used in the calculation of dose uptake in living tissue in both radiation protection (reduction of harmful effects), and radiation oncology (potential beneficial effects, for example in cancer treatment). It is also used to directly compare the effect of radiation on inanimate matter such as in radiation hardening.

The SI unit of measure is the gray (Gy), which is defined as one joule of energy absorbed per kilogram of matter.^[1] The older, non-SI CGS unit rad, is sometimes also used, predominantly in the USA.