Radiotherapy BED & EQD2 (linear-quadratic)
Radiobiology conversion: biologically effective dose (BED) and the 2-Gy-equivalent dose (EQD2) for a fractionation schedule, from the linear-quadratic model and the tissue α/β ratio.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Number of fractions
- 30
- Dose per fraction
- 2 Gy
- α/β ratio
- 10 Gy
Result: BED 72 Gy; EQD2 60 Gy (α/β 10).
The tool opens with these values already filled in. Replace them with your own.
What the result means
- α/β
- ≈ 10 Gy for tumor / early-responding tissue, 3 Gy for late-responding normal tissue.
What you enter
- Number of fractions
- Dose per fraction
- α/β ratio
How this is calculated
- Formula
- BED = n·d·(1 + d/(α/β)); EQD2 = BED/(1 + 2/(α/β)).
Fowler JF. The linear-quadratic formula and progress in fractionated radiotherapy. Br J Radiol. 1989;62(740):679-694. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.