Proton Therapy at the Institut Curie – CPO: operation of an IBA C235 cyclotron looking forward scanning techniques

Since 1991, more than 6100 patients (mainly eye and head&neck tumours) were treated at the Institut Curie – Centre de Protonthèrapie d’Orsay (IC – CPO) using Single Scattering and Double Scattering (DS) proton beam delivery technique. After 19 years of activity, a 200 MeV synchrocyclotron has been shut down and replaced by a 230 MeV C235 IBA proton cyclotron. This delivers beam to two passive fixed treatment rooms and to one universal nozzle equipped gantry (DS, Uniform Scanning – US, Pencil Beam Scanning – PBS). In the past two years of operation more than 95.5% of the scheduled patients (near 500/year) were treated without being postponed. According to IBA recommendations, we have realized preventive maintenance and we have improved some diagnostic tools allowing us to reduce the number of downtime events from 499 in 2011 to 351 in 2012 [1]. In order to enhance cancer treatment capabilities we are now involved in the transition towards scanning particle therapy, requiring even more accurate quality assurance protocols. We describe here the main cyclotron issues looking forward the scanning technique, the main goal being the progress of our reliability performances.