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Irradiator Commissioning and Dosimetry for Assessment of LQ α and β Parameters, Radiation Dosing Schema, and in vivo Dose Deposition
Published on: March 11, 2021
Commissioning, Characterization, and First High-Dose-Rate Irradiations at a Compact X-Ray Tube for Microbeam and
Christian Petrich1, Johanna Winter2, Anton Dimroth3
1Department of Radiation Oncology, TUM School of Medicine and Health, TUM University Hospital, Technical University of Munich, Munich, Germany; Department of Physics, School of Natural Sciences, Technical University of Munich, Garching, Germany; Heinz Maier-Leibnitz Zentrum (MLZ), Garching, Germany; Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, Neuherberg, Germany.
A new compact line-focus x-ray tube (LFXT) prototype enables advanced minibeam and microbeam radiation therapy. This technology promises better tumor control and reduced normal tissue toxicity for future clinical applications.
Area of Science:
- Medical Physics
- Radiation Oncology
- X-ray Technology
Background:
- Minibeam and microbeam radiation therapy offer improved outcomes by reducing normal tissue toxicity and enhancing tumor control.
- Current compact radiation sources are limited, restricting clinical use of minibeams to superficial tumors and precluding microbeams.
Purpose of the Study:
- To develop and construct the first prototype of a compact line-focus x-ray tube (LFXT).
- To assess the LFXT's potential for clinical translation of minibeam and microbeam radiation therapy.
Main Methods:
- Commissioning and initial operation of the LFXT prototype.
- Optical and radiological characterization of the focal spot and dosimetric measurements.
- Preclinical in vitro cell and in vivo mouse brain irradiations using the LFXT.
Main Results:
- The LFXT prototype was successfully conditioned up to 300 kV, with a focal spot width of 72.3 μm.
- Dosimetry revealed sharp microbeam profiles with a peak-to-valley dose ratio >10 in a 70-mm PMMA phantom.
- An open-field dose rate of 4.3 Gy/s was achieved; in vitro/in vivo tests confirmed feasibility for 1.5-2 cm field sizes with no observable side effects in mice.
Conclusions:
- The first proof-of-concept LFXT prototype was successfully constructed and commissioned.
- The LFXT demonstrates superior beam quality compared to conventional x-ray tubes for microbeam applications.
- Future developments will address prototype limitations, enabling clinical minibeam and microbeam radiation therapy.
