Absorbed dose
![External dose quantities used in radiation protection and dosimetry](/Images/godic/202412/19/Dose_quantities_and_units4233.png")
![The international Radura logo, used to show a food has been treated with ionizing radiation.](/Images/godic/202412/19/Radura_international.svg4233.png")
![Various doses of radiation in sieverts, ranging from trivial to lethal.](/Images/godic/202412/19/Radiation_Dose_Chart_by_Xkcd4234.png")
Absorbed dose is a physical dose quantity D representing the mean energy imparted to matter per unit mass by ionizing radiation. In the SI system of units, the unit of measure is joules per kilogram, and its special name is gray (Gy). The non-SI CGS unit rad is sometimes also used, predominantly in the USA.