Development of an Assemblable, Daily, Quality-Assurance Device for Line-Scanning Proton Therapy

Proton beam therapy requires a reliable and efficient method of daily quality assurance. Various daily quality-assurance systems were developed for a simple and efficient quality assurance of spot-scanning proton therapy nozzles. To promote the same effectiveness in daily quality assurance of line-scanning proton therapy nozzles, we developed an assemblable, all-in-one, daily, quality-assurance system for line-scanning proton therapy nozzles. The system uses a high-density polyethylene device mounted on a two-dimensional ionization chamber array detector. The device is modularized for routine daily quality-assurance activities (output measurements, range verifications, and scan pattern measurements). A proton beam delivery plan was created for daily quality assurance based on the CT-scanned image of the device. Each step of the daily quality-assurance procedure was tested with the developed system. Using the developed system, proton beam range verifications and gamma analysis of the scan pattern test were combined into a measurement with a single beam delivery. The developed system will improve the efficiency of daily quality assurance for line-scanning nozzles while using an assemblable design to add flexibility.