What does the SI unit "Gray" (Gy) measure in the context of radiation?

The Gray (Gy) is a unit of measurement that specifically quantifies the absorbed dose of ionizing radiation. In radiation therapy and radiology, the absorbed dose is essential because it indicates the amount of energy that radiation deposits in a certain mass of tissue. One Gray is defined as the absorption of one joule of radiation energy by one kilogram of matter, which highlights its focus on the effects of radiation on biological tissues.

Understanding the absorbed dose is crucial for medical professionals as it helps them determine the potential biological effects of radiation exposure, gauge the efficacy of radiation treatments, and ensure patient safety. This makes the measurement of absorbed dose a central consideration in both diagnostic imaging and treatment planning. Other units, such as the sievert (Sv), may measure the biological effect of the absorbed dose, but the Gray specifically refers to the amount of energy absorbed and does not account for the type of radiation or its biological impact.