Evaluation of a magnetic resonance guided linear accelerator for stereotactic radiosurgery treatment. Issue 3 (June 2018)

• Record Type: Journal Article
• Authors: Wen, Ning; Kim, Joshua; Doemer, Anthony; Glide-Hurst, Carri; Chetty, Indrin J.; Liu, Chang; Laugeman, Eric; Xhaferllari, Ilma; Kumarasiri, Akila; Victoria, James; Bellon, Maria; Kalkanis, Steve; Siddiqui, M. Salim; Movsas, Benjamin
• Is Part Of: Radiotherapy and oncology. Volume 127:Issue 3(2018)
• Page Start: 460
• Page End: 466
• Publication Date: 2018-06
• Subjects: MR-Linac -- Stereotactic radiosurgery -- Accuracy -- Single isocenter multiple targets; Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2018.04.034
• Languages: English
• ISSNs: 0167-8140

Abstract

Abstract: Introduction: The purpose of this study was to investigate the systematic localization accuracy, treatment planning capability, and delivery accuracy of an integrated magnetic resonance imaging guided Linear Accelerator (MR-Linac) platform for stereotactic radiosurgery. Materials and methods: The phantom for the end-to-end test comprises three different compartments: a rectangular MR/CT target phantom, a Winston–Lutz cube, and a rectangular MR/CT isocenter phantom. Hidden target tests were performed at gantry angles of 0, 90, 180, and 270 degrees to quantify the systematic accuracy. Five patient plans with a total of eleven lesions were used to evaluate the dosimetric accuracy. Single-isocenter IMRT treatment plans using 10–15 coplanar beams were generated to treat the multiple metastases. Results: The end-to-end localization accuracy of the system was 1.0 ± 0.1 mm. The conformity index, homogeneity index and gradient index of the plans were 1.26 ± 0.22, 1.22 ± 0.10, and 5.38 ± 1.44, respectively. The average absolute point dose difference between measured and calculated dose was 1.64 ± 1.90%, and the mean percentage of points passing the 3%/1 mm gamma criteria was 96.87%. Conclusions: Our experience demonstrates that excellent plan quality and delivery accuracy was achievable on the MR-Linac for treating multiple brain metastases with a single isocenter.