Biologically effective dose (BED) and EQD2
A way of converting any radiotherapy schedule into a common currency so that, say, five big doses can be compared with 25 small ones. EQD2 expresses the same thing as the equivalent total dose in 2 Gy fractions.
Overview
Because the effect of radiation depends on fraction size as well as total dose, physicists calculate the biologically effective dose from the total dose, the dose per fraction and the tissue's alpha/beta ratio. EQD2 rescales this to the dose that would have the same effect if given in 2 Gy fractions, the historical standard. Both are used to design hypofractionated schedules, sum doses in re-irradiation and compare brachytherapy with external beam.
Showing the technology this term belongs to: The linear-quadratic model and fractionation.
Similar pages
not linked directly; found by shared links- TermAlpha/beta ratio
Shares The linear-quadratic model and fractionation, Hypofractionated radiotherapy and the tag radiation-wave1.
- TermBrachytherapy (internal radiotherapy)
- TermGray unit (Gy)
Shares The linear-quadratic model and fractionation, Re-irradiation.
- TermHypofractionation (fewer, larger radiotherapy doses)
Shares The linear-quadratic model and fractionation, Hypofractionated radiotherapy.