Relative biological effectiveness

Definition

Relative Biological Effectiveness (RBE) is a measure of the effectiveness of ionizing radiation in causing biological damage. It compares the dose of a test radiation to the dose of a reference radiation (usually X-rays or gamma rays) that produces the same biological effect.

5 Must Know Facts For Your Next Test

1. The RBE value depends on the type and energy of radiation.
2. RBE is used to compare different types of radiation, such as alpha particles, beta particles, and gamma rays, in terms of their biological impact.
3. The standard reference for RBE calculations is typically 250 keV X-rays or cobalt-60 gamma rays.
4. Higher LET (Linear Energy Transfer) radiations generally have higher RBE values.
5. RBE is crucial for understanding and evaluating the risks associated with exposure to different types of ionizing radiation.

Review Questions

• What does Relative Biological Effectiveness (RBE) measure?
• Why are 250 keV X-rays or cobalt-60 gamma rays often used as references in RBE calculations?
• How does Linear Energy Transfer (LET) relate to Relative Biological Effectiveness?

Related terms

Linear Energy Transfer (LET): The amount of energy transferred by ionizing radiation per unit length of tissue traveled.

Ionizing Radiation:

Radiation with enough energy to remove tightly bound electrons from atoms, creating ions.

Sievert (Sv): A unit used to measure the health effect of ionizing radiation, taking into account the type of radiation and its biological effects.