BED calculation
Mathematical model comparing biological effectiveness of different radiation fractionation schemes.
Full Definition
Biologically Effective Dose (BED) calculation is a radiobiological model that allows comparison of different radiation fractionation schedules by accounting for the repair of sublethal damage between fractions. The linear-quadratic model forms the basis for BED calculations, incorporating the α/β ratio specific to different tissues and tumor types. BED enables clinicians to compare conventional fractionation with hypofractionated or hyperfractionated regimens on a biologically equivalent basis. The calculation is particularly important in stereotactic radiotherapy, where very high doses per fraction are used, and in situations where treatment schedules must be modified due to interruptions or patient factors.
Usage
Usage note: Requires specification of α/β ratio for accurate comparison between regimens.
In Context
- "The BED calculation confirmed biological equivalence between the two fractionation schemes." — radiobiology analysis
- "Using an α/β ratio of 3 Gy, the BED calculation showed excessive normal tissue dose." — treatment planning review