Technical and dosimetric realization of in vivo x-ray microbeam irradiations at the Munich Compact Light Source.

Autor: Burger K; Department of Radiation Oncology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, 81675, Germany.; Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, 85748, Germany., Urban T; Department of Radiation Oncology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, 81675, Germany.; Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, 85748, Germany., Dombrowsky AC; Department of Radiation Oncology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, 81675, Germany.; Institute of Radiation Medicine (IRM), Department of Radiation Sciences (DRS), Helmholtz Zentrum München, Neuherberg, 85764, Germany., Dierolf M; Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, 85748, Germany., Günther B; Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, 85748, Germany., Bartzsch S; Department of Radiation Oncology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, 81675, Germany.; Institute of Radiation Medicine (IRM), Department of Radiation Sciences (DRS), Helmholtz Zentrum München, Neuherberg, 85764, Germany., Achterhold K; Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, 85748, Germany., Combs SE; Department of Radiation Oncology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, 81675, Germany.; Institute of Radiation Medicine (IRM), Department of Radiation Sciences (DRS), Helmholtz Zentrum München, Neuherberg, 85764, Germany., Schmid TE; Department of Radiation Oncology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, 81675, Germany.; Institute of Radiation Medicine (IRM), Department of Radiation Sciences (DRS), Helmholtz Zentrum München, Neuherberg, 85764, Germany., Wilkens JJ; Department of Radiation Oncology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, 81675, Germany.; Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, 85748, Germany., Pfeiffer F; Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, 85748, Germany.; Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, München, 81675, Germany.
Jazyk: angličtina
Zdroj: Medical physics [Med Phys] 2020 Oct; Vol. 47 (10), pp. 5183-5193. Date of Electronic Publication: 2020 Aug 27.
DOI: 10.1002/mp.14433
Abstrakt: Purpose: X-ray microbeam radiation therapy is a preclinical concept for tumor treatment promising tissue sparing and enhanced tumor control. With its spatially separated, periodic micrometer-sized pattern, this method requires a high dose rate and a collimated beam typically available at large synchrotron radiation facilities. To treat small animals with microbeams in a laboratory-sized environment, we developed a dedicated irradiation system at the Munich Compact Light Source (MuCLS).
Methods: A specially made beam collimation optic allows to increase x-ray fluence rate at the position of the target. Monte Carlo simulations and measurements were conducted for accurate microbeam dosimetry. The dose during irradiation is determined by a calibrated flux monitoring system. Moreover, a positioning system including mouse monitoring was built.
Results: We successfully commissioned the in vivo microbeam irradiation system for an exemplary xenograft tumor model in the mouse ear. By beam collimation, a dose rate of up to 5.3 Gy/min at 25 keV was achieved. Microbeam irradiations using a tungsten collimator with 50 μm slit size and 350 μm center-to-center spacing were performed at a mean dose rate of 0.6 Gy/min showing a high peak-to-valley dose ratio of about 200 in the mouse ear. The maximum circular field size of 3.5 mm in diameter can be enlarged using field patching.
Conclusions: This study shows that we can perform in vivo microbeam experiments at the MuCLS with a dedicated dosimetry and positioning system to advance this promising radiation therapy method at commercially available compact microbeam sources. Peak doses of up to 100 Gy per treatment seem feasible considering a recent upgrade for higher photon flux. The system can be adapted for tumor treatment in different animal models, for example, in the hind leg.
(© 2020 The Authors. Medical Physics published by Wiley Periodicals LLC on behalf of American Association of Physicists in Medicine.)
Databáze: MEDLINE
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