Particle Therapy 2017

New photon technology

IMRT: arbitrary sharp dose gradients concave dose distributions

IGRT/gating/tracking: reducing PTV-margins

reducing surrounding dose Adaptive/painting: reducing CTV (sub)volumes reducing surrounding dose

Is the best tool to explore new clinical directions* Technology development much faster for photons Advantage of photons consolidated by faster upgrading Improves treatment in existing clinical indications

Fundamental disadvantage of protons

Degradation of lateral penumbra in depth

Gradient near PTV, nearby small or sensitive OAR

Loss of the Bragg peak using small pencils Fine painting Small targets

*Early recurrence, immunogenic/vascular cancercell death, synchronous and metachronous painting, (oligo)metastatic disease, elective nodal instead of elective compartmental irradiation