Comparison of Clinical Parameters for Proton Therapy in the United States Paige Summers, MS

Disclosure This project is supported by the Federal Share of program income earned by Massachusetts General Hospital on C06 CA059267, Proton Therapy Research and Treatment Center and by grants CA10953 and CA81647 (NCI, DHHS).

RPC Background Funded by the NCI, tasked with ensuring that radiotherapy institutions participating in clinical trials deliver clinically comparable and consistent doses Asked to develop monitoring program for proton therapy facilities too

Proton Therapy Facilities Monitored by RPC: 10 clinical sites 1 international site in Japan Forecast ~20 new centers Will likely see increase in clinical trials with proton therapy, making comparability important NJ 2012 Shizuoka 2003

Proton Approval Steps Proton facility questionnaire Annual monitoring of beam calibrations by the RPC Ability to electronically transfer treatment plans Irradiation of RPC’s baseline proton phantoms On-site dosimetry review visit

Information Collected by the RPC Typical review components: Dosimetry equipment calibration CT scanner, CTN/RSP conversion Patient immobilization Treatment planning procedures QA documentation

Patient Simulation Parameters InstitutionScannerkVpmAsSlice ThicknessAcquisition ModePitchSFOV [cm] 1GE LightSpeed RT mmAxialN/A50 2GE LightSpeed RT mmHelical Philips PET / Big Bore120 / / mmHelical0.51 / / 85 4GE VCT mmAxial/Helical N/A / Siemens Biograph 16 PET120 / mmHelical Siemens Sensation mmHelical GE LightSpeed RT mmHelical GE LightSpeed RT mmHelical Values obtained during on-site audit Can institutions improve simulation imaging parameters? Lower CT dose?

Treatment Margins Described by institution in facility questionnaire Site-Specific Lateral Margins [mm] BrainH&NAbdomenPelvis Institution Institution Institution Institution Institution Institution Institution Institution Institution Institution Institution Penetration Uncertainty Margins Institution 13% Institution 23.5% + 3mm Institution 31.50% Institution 43.5% + 3mm Institution 52 mm Institution 63.5% + 3mm Institution 71% + 1mm Institution 81.5% + 1.5mm Institution 9- Institution 101% + 1mm Institution 113.5% + 3mm

Prescribing Dose Prescription Levels BrainH&NThoraxAbdomenPelvisExtremities Institution % Institution %- 97.5%- Institution 395%92%95% Institution 4100% Institution 5100% Institution 698% Institution 795% Institution 898% Institution 995% Institution 1095% Institution 1195% Institutions normalizing in different ways, to different levels

Significance Differences exits across centers Task groups focusing on QA, papers on outcomes – not many recommendations about clinical parameters - could use more recommendations from experienced proton centers Important to consider variation of dosimetric parameters in planning clinical trials – proton alone or mixed modality

Questions? ??

Proton Approval Steps Proton facility questionnaire Annual monitoring of beam calibrations by the RPC Ability to electronically transfer treatment plans Successful irradiation of RPC’s baseline proton phantoms Successful completion of on-site dosimetry review visit

Facility Questionnaire AAPM Proton Advisory group aids RPC & QARC in updating proton facility questionnaire Submitted to QARC via or paper – copy sent to RPC Questions covered: Experiences in the clinic Dose calibration & verification Proton beam production & delivery Treatment Planning Immobilization Patient Alignment QA

RPC Proton Site Visits Typical site visit measurements Beam calibration comparison – RPC/Inst CAX lateral and depth dose profiles for reference and patient fields Scanning beam – less fields tested, more profiles obtained X-ray system measurements TLD measurements