26th EURADOS Webinar: Secondary Radiation in a Compact Proton Therapy System скачать в хорошем качестве

26th EURADOS Webinar: Secondary Radiation in a Compact Proton Therapy System

26th EURADOS Webinar: Secondary Radiation in a Compact Proton Therapy System with a Gantry-Mounted Synchrocyclotron - EURADOS Insights and Results Overview Proton therapy is known for its precise dose delivery, but secondary radiation—especially neutrons—remains a challenge for patient radiation protection. Understanding and accurately measuring these unwanted doses is crucial, particularly for new techniques like the compact proton therapy systems Mevion S250i Hyperscan, where the synchrocyclotron is mounted directly on the rotating gantry. Mevion S250i Hyperscan provides a scanned 227 MeV proton beam, delivered in pulses with a pulse width of 10 μs at 750 Hz frequency, which is afterwards degraded in energy by an energy modulator system. EURADOS Working Groups WG9 (Radiation dosimetry in radiotherapy) and WG11 (High-Energy Radiation Dosimetry) joined forces to investigate the neutron and gamma radiation fields generated in this unique system. In the last 10 years WG9 has conducted comprehensive measurements of out-of-field neutron and photon doses inside water phantoms and pediatric anthropomorphic phantoms irradiated with photon and proton systems. By using a well-characterized set of passive detectors and advanced spectrometry systems available among our members, WG9 has produced high-quality dosimetric data that enhance understanding of secondary and scattered radiation fields. WG11 has extensive experience in high-energy neutron dosimetry in pulsed fields using rem counters, valuable tools for on-line assessment of neutron H*(10). However, selecting an appropriate survey meter requires proper prior knowledge of the facility and radiation field. The Mevion proton beam, delivered in 10 μs pulses at 750 Hz, poses unique challenges for commercial rem counters, due to both its energy and time structure. We tested the reliability of widely used rem counters to evaluate their limits in this stray neutron field. This webinar will present key insights from our experimental campaign at compact proton therapy systems Mevion S250i Hyperscan, focusing on: Agenda Welcome & Introduction (Liliana Stolarczyk) Proton Therapy Facility with a Gantry-Mounted synchrocyclotron (Gloria Vilches-Freixas) Assessing Secondary Radiation: Insights from Passive Detector Measurements (Marie Davidkova) Active Detectors in Pulsed Proton Fields: Challenges & Findings (Gabriele Zorloni) Unfolding the Spectrum - Results of neutron spectrometry (Carles Domingo) Q&A