Emil Schüler1, Stefania Trovati1, Gregory King1, Frederick Lartey1, Marjan Rafat1, Manuel Villegas1, A Joe Praxel1, Billy W Loo2, Peter G Maxim3. 1. Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California. 2. Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California. Electronic address: BWLoo@stanford.edu. 3. Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California. Electronic address: PMaxim@stanford.edu.
Abstract
PURPOSE: A key factor limiting the effectiveness of radiation therapy is normal tissue toxicity, and recent preclinical data have shown that ultra-high dose rate irradiation (>50 Gy/s, "FLASH") potentially mitigates this effect. However, research in this field has been strongly limited by the availability of FLASH irradiators suitable for small animal experiments. We present a simple methodologic approach for FLASH electron small animal irradiation with a clinically available linear accelerator (LINAC). METHODS AND MATERIALS: We investigated the FLASH irradiation potential of a Varian Clinac 21EX in both clinical mode and after tuning of the LINAC. We performed detailed FLUKA Monte Carlo and experimental dosimetric characterization at multiple experimental locations within the LINAC head. RESULTS: Average dose rates of ≤74 Gy/s were achieved in clinical mode, and the dose rate after tuning exceeded 900 Gy/s. We obtained 220 Gy/s at 1-cm depth for a >4-cm field size with 90% homogeneity throughout a 2-cm-thick volume. CONCLUSIONS: We present an approach for using a clinical LINAC for FLASH irradiation. We obtained dose rates exceeding 200 Gy/s after simple tuning of the LINAC, with excellent dosimetric properties for small animal experiments. This will allow for increased availability of FLASH irradiation to the general research community.
PURPOSE: A key factor limiting the effectiveness of radiation therapy is normal tissue toxicity, and recent preclinical data have shown that ultra-high dose rate irradiation (>50 Gy/s, "FLASH") potentially mitigates this effect. However, research in this field has been strongly limited by the availability of FLASH irradiators suitable for small animal experiments. We present a simple methodologic approach for FLASH electron small animal irradiation with a clinically available linear accelerator (LINAC). METHODS AND MATERIALS: We investigated the FLASH irradiation potential of a Varian Clinac 21EX in both clinical mode and after tuning of the LINAC. We performed detailed FLUKA Monte Carlo and experimental dosimetric characterization at multiple experimental locations within the LINAC head. RESULTS: Average dose rates of ≤74 Gy/s were achieved in clinical mode, and the dose rate after tuning exceeded 900 Gy/s. We obtained 220 Gy/s at 1-cm depth for a >4-cm field size with 90% homogeneity throughout a 2-cm-thick volume. CONCLUSIONS: We present an approach for using a clinical LINAC for FLASH irradiation. We obtained dose rates exceeding 200 Gy/s after simple tuning of the LINAC, with excellent dosimetric properties for small animal experiments. This will allow for increased availability of FLASH irradiation to the general research community.
Authors: Eric S Diffenderfer; Ioannis I Verginadis; Michele M Kim; Khayrullo Shoniyozov; Anastasia Velalopoulou; Denisa Goia; Mary Putt; Sarah Hagan; Stephen Avery; Kevin Teo; Wei Zou; Alexander Lin; Samuel Swisher-McClure; Cameron Koch; Ann R Kennedy; Andy Minn; Amit Maity; Theresa M Busch; Lei Dong; Costas Koumenis; James Metz; Keith A Cengel Journal: Int J Radiat Oncol Biol Phys Date: 2020-02-01 Impact factor: 7.038
Authors: Jinghui Wang; Stefania Trovati; Philipp M Borchard; Billy W Loo; Peter G Maxim; Rebecca Fahrig Journal: Med Phys Date: 2017-11-06 Impact factor: 4.071