Proton relative biological effectiveness — uncertainties and opportunities

Review of proton RBE. It explains that proton prescriptions and organ constraints are based on physical dose multiplied by a generic constant RBE of 1.1, derived from early in vivo measurements; that RBE varies with LET, dose, biological endpoint and tissue radiosensitivity; and gives typical dose-averaged LET values across a spread-out Bragg peak, rising from about 0–3 keV/µm up to the center to 9–15 keV/µm in the dose fall-off, with the rise in LET and RBE extending the biologically effective range by 1 to 2 mm. Read in Europe PMC (PMC6200410).

A shorter companion to TG-256: where the clinical proton RBE of 1.1 came from, and typical LET values across a spread-out Bragg peak.