LET-based plans optimise proton therapy

In clinical practice today, proton therapy is planned assuming a constant value of 1.1 for the relative biological effectiveness (RBE) of protons. RBE, however, is a complex variable that depends on many factors and – despite extensive research – there is no accepted variable RBE model available for use in clinical treatment planning. As such, the biological uncertainties of protons remain a major challenge for realising the full potential of proton therapy.
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