When do I use EQD2 instead of BED?

EQD2 is used when comparing normal tissue toxicity across different schedules, since it directly expresses the dose in clinically familiar 2 Gy units. BED is more useful for comparing tumour control.

Does a higher EQD2 always mean more toxicity?

For late-reacting tissues (a/b = 3), hypofractionated regimens can have higher EQD2 than conventionally fractionated courses with the same BED, meaning more late normal tissue effect.

EQD2 - Equivalent Dose in 2 Gy Fractions

Convert any fractionation scheme to EQD2 for comparison. EQD2 = BED / (1 + 2/(a/b)) = nd x (d + a/b) / (2 + a/b). Allows comparison of hypofractionated and conventional schedules on a common scale.

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EQD2 - Equivalent Dose in 2 Gy Fractions

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Frequently Asked Questions

When do I use EQD2 instead of BED?

Does a higher EQD2 always mean more toxicity?