A systematic review on the usage of averaged LET in radiation biology for particle therapy

Linear Energy Transfer (LET) is widely used to express the radiation quality of ion beams, when characterizing biological effectiveness. However, averaged LET may be defined in multiple ways, and chosen definition impact resulting reported value. We review definitions found literature, quantify which using these various have for different reference setups. recorded 354 publications quantifying relative effectiveness (RBE) hadronic investigated how a Monte Carlo particle transport code. find that kind being applied is, generally, poorly defined. Some influence values up an order magnitude. For involving protons, most dose reporting RBE. The absence what target medium secondary particles are included further contributes ill-defined LET. also evidence inconsistent usage deriving LET-based RBE models. To conclude, due commonly inherent problems models, only as coarse indicator quality. propose more rigorous way values, suggest ideally entire fluence spectra should provided future studies, from any type (or other quantities) inferred.