Absorbed Dose
The physical quantity measuring the amount of energy deposited by ionizing radiation per unit mass of matter.
Governing formula
D = dE / dm, 1 Gy = 1 J / kg = 100 rad
SI unit
Gy (Gray = J/kg)
In depth
Absorbed dose is a fundamental physical quantity independent of radiation type or biological tissue response. 1 Gray equals 1 Joule of energy absorbed per kilogram of mass.
Examples in the real world
Delivering a cumulative absorbed dose of 60 Gy to a solid tumor over a 6-week radiotherapy treatment course.