Walter Tinganelli1, Olga Sokol1, Martina Quartieri1, Anggraeini Puspitasari1, Ivana Dokic2, Amir Abdollahi2, Marco Durante3, Thomas Haberer4, Jürgen Debus5, Daria Boscolo1, Bernd Voss1, Stephan Brons4, Christoph Schuy1, Felix Horst1, Ulrich Weber1. 1. Biophysics Department, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt. 2. Heidelberg Ion-Beam Therapy Center, Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg; Clinical Cooperation Unit Radiation Oncology, Heidelberg Institute of Radiation Oncology, National Center for Radiation Oncology, National Center füor Tumor Diseases, Heidelberg University and German Cancer Research Center, Heidelberg. 3. Biophysics Department, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt; Institut für Festkörperphysik, Technische Universität Darmstadt, Darmstadt. Electronic address: m.durante@gsi.de. 4. Heidelberg Ion-Beam Therapy Center, Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg. 5. Clinical Cooperation Unit Radiation Oncology, Heidelberg Institute of Radiation Oncology, National Center for Radiation Oncology, National Center füor Tumor Diseases, Heidelberg University and German Cancer Research Center, Heidelberg; Division of Molecular and Translational Radiation Oncology, Department of Radiation Oncology, Heidelberg Faculty of Medicine and Heidelberg University Hospital, Heidelberg Ion-Beam Therapy Center, Heidelberg; German Cancer Consortium Core-Center Heidelberg, German Cancer Research Center, Heidelberg, Germany.
Abstract
PURPOSE: To establish a beam monitoring and dosimetry system to enable the FLASH dose rate carbon ion irradiation and investigate, at different oxygen concentrations, the in vitro biological response in comparison to the conventional dose rate. METHODS AND MATERIALS: CHO-K1 cell response to irradiation at different dose rates and at different levels of oxygenation was studied using clonogenic assay. The Heidelberg Ion-Beam Therapy Center (HIT) synchrotron, after technical improvements, was adjusted to extract ≥5 × 108 12C ions within approximately 150 milliseconds. The beam monitors were filled with helium. RESULTS: The FLASH irradiation with beam scanning yields a dose of 7.5 Gy (homogeneity of ±5%) for a 280 MeV/u beam in a volume of at least 8 mm in diameter and a corresponding dose rate of 70 Gy/s (±20%). The dose repetition accuracy is better than 2%, the systematic uncertainty is better than 2%. Clonogenic assay demonstrates a significant FLASH sparing effect which is strongly oxygenation-dependent and mostly pronounced at 0.5% O2 but absent at 0% and 21% O2. CONCLUSION: The FLASH dose rates >40 Gy/s were achieved with carbon beams. Cell survival analysis revealed FLASH dose rate sparing in hypoxia (0.5%-4% O2).
PURPOSE: To establish a beam monitoring and dosimetry system to enable the FLASH dose rate carbon ion irradiation and investigate, at different oxygen concentrations, the in vitro biological response in comparison to the conventional dose rate. METHODS AND MATERIALS: CHO-K1 cell response to irradiation at different dose rates and at different levels of oxygenation was studied using clonogenic assay. The Heidelberg Ion-Beam Therapy Center (HIT) synchrotron, after technical improvements, was adjusted to extract ≥5 × 108 12C ions within approximately 150 milliseconds. The beam monitors were filled with helium. RESULTS: The FLASH irradiation with beam scanning yields a dose of 7.5 Gy (homogeneity of ±5%) for a 280 MeV/u beam in a volume of at least 8 mm in diameter and a corresponding dose rate of 70 Gy/s (±20%). The dose repetition accuracy is better than 2%, the systematic uncertainty is better than 2%. Clonogenic assay demonstrates a significant FLASH sparing effect which is strongly oxygenation-dependent and mostly pronounced at 0.5% O2 but absent at 0% and 21% O2. CONCLUSION: The FLASH dose rates >40 Gy/s were achieved with carbon beams. Cell survival analysis revealed FLASH dose rate sparing in hypoxia (0.5%-4% O2).
Authors: Thomas Held; Thomas Tessonnier; Henrik Franke; Sebastian Regnery; Lukas Bauer; Katharina Weusthof; Semi Harrabi; Klaus Herfarth; Andrea Mairani; Jürgen Debus; Sebastian Adeberg Journal: Radiat Oncol Date: 2022-07-08 Impact factor: 4.309
Authors: Francesco Romano; Claude Bailat; Patrik Gonçalves Jorge; Michael Lloyd Franz Lerch; Arash Darafsheh Journal: Med Phys Date: 2022-05-07 Impact factor: 4.506