Gray (unit)
SI unit of absorbed dose of ionizing radiation
The gray (symbol Gy) is the SI Unit used to show how much ionizing radiation someone has been exposed to. It measures how much energy has been deposited, or left behind, in someone. It is used frequently in medicine, such as in radiotherapy, and they are also used to diagnose people. Grays are important in figuring out if someone has acute radiation syndrome, for example. Grays are used frequently in radiation protection. They are an important unit in figuring out what health effects someone may have from exposure. Grays are used internationally in order to calculate how much radiation someone has in their body. They are used in many different fields and have many uses.