Revealing the underlying mechanism of microbeam radiation therapy with low energy Monte Carlo simulations

17th International Conference on the Use of Computers in Radiation Therapy

物理学;计算机科学

McNamara, A.L.^1 ; Oelfke, U.^2 ; Kuncic, Z.^1

Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, Australia^1

Department of Medical Physics Radiation Oncology, DKFZ Heidelberg, University of Heidelberg, Germany^2

关键词: Biological response;    Cluster distributions;    Conventional radiation therapy;    Higher energy beams;    Irreversible damage;    Microbeam Radiation Therapy;    Secondary electrons;    Transport simulation;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/489/1/012018/pdf
DOI  :  10.1088/1742-6596/489/1/012018

学科分类：计算机科学（综合）

来源: IOP

【 摘 要 】

Microbeam radiation therapy (MRT) is a new experimental oncological modality, intended for the treatment of inoperable brain tumours, particularly in difficult cases where conventional radiation therapy can cause irreversible damage. MRT consists of an array of highly collimated, quasi-parallel x-ray microbeams aimed at the tumour tissue, delivering high dose within the beam path and low doses in regions between the beams. For reasons still not fully understood, healthy tissue exposed to the microbeam array is able to regenerate while tumour volumes are significantly reduced. Low energy Monte Carlo radiative transport simulations provide new insight into understanding the underlying mechanisms of MRT. In particular, predicting the ionisation cluster distribution, which is a significant cause of lethal damage to cells, would provide insight into the biological responses. Geant4-DNA was used to model an x-ray microbeam of width 20 μm in liquid water. Secondary electrons, predominately responsible for ionisation clustering, were tracked to predict damage to cells within and adjacent to the beams. We find that higher energy beams (100 keV) produce less secondary electrons in the regions outside the beam than low energy beams (30-50 keV).