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    Radiation Biologically Effective Dose (BED) Calculator

    Calculates biologically effective dose (BED) and equivalent dose (EQD2) for cancer radiotherapy.
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    Patients undergoing radiation (to compare different fractionation regimens).

    • Note that BED is the biologically effective dose, not biologically equivalent dose.

    • EQD2 is the equivalent dose in 2-Gy fractions.

    • An α/β ratio of 10 is typically used for early-responding tissues and tumors.

    • An α/β ratio of 3 is typically used for late-responding tissues, such as normal tissue.

    • Prostate cancer has a low α/β ratio of ~1.5.

    Compares different fractionation regimens with hypofractionation or stereotactic body radiation therapy (SBRT) using a common numerical score.

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    Can also be used to determine total dose received over multiple radiation courses.

    Formula

    BED = D x (1 + [d / (α/β)])

    EQD2 = D x ([d + (α/β)] / [2 Gy + (α/β)])  

     

    Where variables are as follows:

    Variable

    Description

    BED

    Biologically effective dose, in Gy

    EQD2

    Equivalent dose in 2-Gy fractions, in Gy

    d

    Dose per fraction, in Gy

    D

    Total dose (number of fractions x dose per fraction), in Gy

    α/β ratio

    Property of irradiated tissue

    Dr. John F. Fowler

    About the Creator

    John F. Fowler, DSc, PhD, FInsTP, (d. 2016) was the director of the Gray Laboratory at Mount Vernon Hospital in England, UK. He also served as president of the Hospital Physicists Association, European Society of Radiation Biology, and the British Institute of Radiology. Dr. Fowler’s primary research was focused on dose fractionation and tumor control.

    To view Dr. John F. Fowler's publications, visit PubMed

    Content Contributors
    • Neil Panjwani, MD
    Reviewed By
    • Hilary Bagshaw, MD
    About the Creator
    Dr. John F. Fowler
    Content Contributors
    • Neil Panjwani, MD
    Reviewed By
    • Hilary Bagshaw, MD