Numerous distinct units, acknowledged on a global scale as SI units, are employed to quantify ionizing radiation. For instance, the becquerel (symbol Bq) serves as the SI unit for the inherent activity of a radioactive source, like uranium. In medical contexts, the gray (symbol Gy) and the sievert (symbol Sv) are the most frequently utilized units.
The gray stands as the SI unit measuring the radiation effectively taken in by any material or tissue when exposed to radiation. Specifically, one gray corresponds to the absorption of one joule of energy (originating from gamma radiation or X-rays) for every kilogram of irradiated substance. The gray has replaced an earlier unit known as the rad (1 Gy = 100 rads).
Given that certain forms of radiation exert varying effects on living organisms, the sievert serves as a gauge to assess the influence of an absorbed dose. It incorporates supplementary factors, including the type of radiation and its energy, to quantify the repercussions on the body stemming from equivalent quantities of distinct absorbed energies.