SI derived unit of energy imparted to an element of matter by ionizing radiation divided by the mass of that element (absorbed dose of radiation) equal to one joule per kilogram and admitted for reasons of safeguarding human health, Gy = J kg −1.
PAC, 1996, 68, 957 (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 975