Quality assurance program for CatalystTM, a 3D surface imaging system for patient setup verification in radiotherapy

Abstract

Introduction The aim of this study is to come up with a quality assurance program for CatalystTM (C-Rad, Uppsala, Sweden), a ‘‘non-radiographic” patient setup verification device. Materiel and methods The Catalyst system consists of an optical surface scanning and re-projection device mounted in the ceiling in front of our Varian clinac. The system gives an instant feedback during the patient repositioning and is designed to be integrated in the treatment workflow. The software is interfaced with our clinac console, the motorized couch and the R&V system: ARIA. This report presents the acceptance and the commissioning we performed for this new equipment installed in our center. A quality assurance program has also been established to maintain the safety, accuracy, precision sensitivity and reliability of this patient positioning system in time. Results Acceptance testing provided by the supplier has been made during the installation. These tests are useful to become familiar with equipment operation and its limitations and demonstrate that the equipment is working. The commissioning procedures have been based on the AAPM task group report 147. The main parts of these tests are integration of equipment, measurements of spatial reproducibility and drift and estimation of the localization accuracy. All of this led us to a better understanding of Catalyst and allowed us to establish a complete quality program. The communication and the integration of Catalyst with all our equipment are fully functional. We only detected a potential misusage when we import a treatment plan with multiple isocentres. During the first six months, the daily check operation shows less than 1 mm deviation in all directions, with a mean of 0.6 ± 0.3 mm. And we did not observe any spatial drift due to the system warm-up. Reproducibility of surface acquisition and setup procedure was better than 0.5 mm and 0.5° and 1 mm and 1°, respectively. The system accuracy was better than 1 mm and 1° hen a catalyst image was used as reference. A global worsening was observed using an external surface extracted from CT study. Conclusion This localization and positioning system is expected to become an important component within our radiation therapy process, so a quality assurance of this system is essential. Moreover, this study allows us to refine and to adapt our clinical procedure. The aim of this study is to come up with a quality assurance program for CatalystTM (C-Rad, Uppsala, Sweden), a ‘‘non-radiographic” patient setup verification device. The Catalyst system consists of an optical surface scanning and re-projection device mounted in the ceiling in front of our Varian clinac. The system gives an instant feedback during the patient repositioning and is designed to be integrated in the treatment workflow. The software is interfaced with our clinac console, the motorized couch and the R&V system: ARIA. This report presents the acceptance and the commissioning we performed for this new equipment installed in our center. A quality assurance program has also been established to maintain the safety, accuracy, precision sensitivity and reliability of this patient positioning system in time. Acceptance testing provided by the supplier has been made during the installation. These tests are useful to become familiar with equipment operation and its limitations and demonstrate that the equipment is working. The commissioning procedures have been based on the AAPM task group report 147. The main parts of these tests are integration of equipment, measurements of spatial reproducibility and drift and estimation of the localization accuracy. All of this led us to a better understanding of Catalyst and allowed us to establish a complete quality program. The communication and the integration of Catalyst with all our equipment are fully functional. We only detected a potential misusage when we import a treatment plan with multiple isocentres. During the first six months, the daily check operation shows less than 1 mm deviation in all directions, with a mean of 0.6 ± 0.3 mm. And we did not observe any spatial drift due to the system warm-up. Reproducibility of surface acquisition and setup procedure was better than 0.5 mm and 0.5° and 1 mm and 1°, respectively. The system accuracy was better than 1 mm and 1° hen a catalyst image was used as reference. A global worsening was observed using an external surface extracted from CT study. This localization and positioning system is expected to become an important component within our radiation therapy process, so a quality assurance of this system is essential.