Particle Therapy 2017

RBE for protons • Effect is diluted by contributions of higher energies • Clinically, a value of 1.1 is adopted  • Increased RBE potentially relevant at distal edge • RBE may lead to effective over‐range of 1‐2mm

(Paganetti 2002)

(in-vitro studies, Center of SOBP)

(in-vivo studies, Center of SOBP)

LET optimization and range effects are discussed No clinical proton RBE has ever been determined!