biologically effective dose
Also written as: BED — Biologically Effective Dose
Mathematical model comparing different fractionation schemes based on their biological effects on tissues.
Full Definition
The biologically effective dose (BED) is a calculated value that allows comparison of different radiation fractionation schedules by accounting for the biological response of tissues to radiation dose per fraction. The BED calculation incorporates the linear-quadratic model parameters (α/β ratios) that describe tissue sensitivity to fractionation. This concept is particularly important in hypofractionated treatments, stereotactic radiosurgery, and when converting between different fractionation schemes while maintaining equivalent biological effects.
Usage
Usage note: Requires specification of α/β ratio when reporting BED values.
In Context
- "The biologically effective dose for the SBRT regimen was calculated to be equivalent to 75 Gy in 2-Gy fractions." — Treatment protocol
- "BED calculations indicated that the hypofractionated schedule would provide similar tumor control." — Clinical study report