Petrich Christian, Winter Johanna, Dimroth Anton, Wilkens Jan J, Bartzsch Stefan
TUM School of Natural Sciences, Technical University of Munich (TUM), Garching, Germany; Department of Radiation Oncology, TUM School of Medicine and Health and Klinikum rechts der Isar, TUM University Hospital, Technical University of Munich (TUM), Munich, Germany; Institute of Radiation Medicine, Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Neuherberg, Germany; Forschungs-Neutronenquelle Heinz Maier-Leibnitz Zentrum (FRM II), Technical University of Munich (TUM), Garching, Germany.
Department of Radiation Oncology, TUM School of Medicine and Health and Klinikum rechts der Isar, TUM University Hospital, Technical University of Munich (TUM), Munich, Germany; Institute of Radiation Medicine, Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Neuherberg, Germany; Forschungs-Neutronenquelle Heinz Maier-Leibnitz Zentrum (FRM II), Technical University of Munich (TUM), Garching, Germany.
Phys Med. 2025 Jan;129:104861. doi: 10.1016/j.ejmp.2024.104861. Epub 2024 Dec 26.
Microbeam radiation therapy (MRT) has shown superior healthy tissue sparing at equal tumour control probabilities compared to conventional radiation therapy in many preclinical studies. The limitation to preclinical research arises from a lack of suitable radiation sources for clinical application of MRT due to high demands on beam quality. To overcome these limitations, we developed and built the first prototype of a line-focus X-ray tube (LFXT). During commissioning, characterisation of the X-ray focal spot is necessary. For the generation of microbeams, we require a specially designed collimator adapted to the LFXT.
We present an adapted edge method and a pinhole method for focal spot measurements of the LFXT prototype as well as the design of the microbeam collimator with a slit width of 50μm, spaced by 400μm. Monte Carlo simulations validated the focal spot measurement techniques and the design of the collimator.
We showed that the adapted edge method is more complex but superior to the adapted pinhole method in terms of quantitative validity. Simulations for the microbeam collimator showed a sharp microbeam dose profile with a peak-to-valley dose ratio (PVDR) above 23 throughout 50 mm of water.
During commissioning, the adapted focal spot visualisation methods will be used to determine the focal spot dimensions and to optimise machine parameters. The LFXT prototype will enable preclinical MRT with significantly higher dose rates than any other compact MRT source and will pave the way for the first clinical trials in a hospital setting.
在许多临床前研究中，与传统放射治疗相比，微束放射治疗（MRT）在同等肿瘤控制概率下显示出对健康组织的更好保护。临床前研究的局限性源于缺乏适用于MRT临床应用的合适辐射源，因为对束流质量要求很高。为了克服这些限制，我们开发并制造了线聚焦X射线管（LFXT）的首个原型。在调试过程中，有必要对X射线焦点进行表征。为了产生微束，我们需要一个专门设计的适用于LFXT的准直器。
我们提出了一种适用于LFXT原型焦点测量的边缘法和针孔法，以及狭缝宽度为50μm、间距为400μm的微束准直器的设计。蒙特卡罗模拟验证了焦点测量技术和准直器的设计。
我们表明，改进后的边缘法更复杂，但在定量有效性方面优于改进后的针孔法。微束准直器的模拟显示，在50mm水模体中，微束剂量分布尖锐，峰谷剂量比（PVDR）超过23。
在调试过程中，改进后的焦点可视化方法将用于确定焦点尺寸并优化机器参数。LFXT原型将使临床前MRT能够以比任何其他紧凑型MRT源更高的剂量率进行，并将为医院环境中的首次临床试验铺平道路。
