Gray (Gy)

Definition

Gray (Gy) is the SI unit for the absorbed dose of ionizing radiation, representing the absorption of one joule of radiation energy per kilogram of matter. It measures the amount of energy deposited by radiation in a substance.

5 Must Know Facts For Your Next Test

1. 1 Gy equals one joule per kilogram (1 J/kg).
2. Gray is used to quantify the absorbed dose in tissues and other materials.
3. In medical contexts, Gy helps assess potential biological effects of radiation exposure.
4. Higher doses measured in gray can lead to more significant biological damage.
5. The gray is often used in radiotherapy to determine the appropriate dose for treating cancer.

Review Questions

• What does one gray (Gy) represent in terms of energy and mass?
• How is gray (Gy) relevant in medical treatments like radiotherapy?
• Why is it important to measure absorbed doses in gray when evaluating biological effects of ionizing radiation?

Related terms

Sievert (Sv): Sievert is the SI unit for measuring the health effect of ionizing radiation on the human body, considering both dose and biological impact.

Radiation Dose: The amount of ionizing radiation absorbed by an object or person, often measured in grays (Gy) or sieverts (Sv).

Ionizing Radiation: Radiation with enough energy to remove tightly bound electrons from atoms, creating ions; includes X-rays, gamma rays, and particle radiation.