Computational techniques for studying the interactions of radiation with matter and applications in radiotherapy physics

放射治疗通常被用作癌症的治疗方法。所有形式的放射治疗都旨在最大限度地杀灭肿瘤细胞，同时限制健康组织的辐射暴露。尽管放射治疗被广泛应用于癌症治疗，但与辐射与物质相互作用有关的基本问题仍然存在。此外，未来可能的治疗方法促使人们研究新的领域。这项研究计划涉及开发和应用复杂的计算机代码，这些代码使用所谓的‘蒙特卡罗’(MC)方法来模拟辐射通过物质的过程。这些MC模拟可用于计算辐射在组织中沉积的能量，以及研究与放射治疗相关的广泛问题。*考虑的现有治疗是近距离放射治疗，在该治疗中，放射源被放置在肿瘤(例如，前列腺、乳腺或眼睛)的旁边或内部。广泛使用的剂量计算算法不准确；一个快速、准确和全面的MC剂量计算程序正在开发中，并将用于研究近距离放射物理学。*在细胞成分和DNA水平上模拟辐射相互作用和辐射诱导的损伤以了解辐射的生物效应越来越受到人们的关注。对包括细胞及其组件在内的微观组织结构的模拟提出了计算挑战；此外，可能需要在非常低的能量和短距离尺度下采用与现代量子物理一致的新方法。将开发在多个尺度上模拟辐射传输的新方法，从患者水平向下到组织中的细胞和细胞成分。这些技术将被应用于了解不同辐射源在组织内的能量沉积模式，从而发展对辐射的生物效应的理解。这些新的计算方法还将被用于研究未来可能的治疗技术，如使用纳米设备进行放射治疗和其他靶向治疗。*这项研究将促进我们对辐射与物质的相互作用和辐射剂量学的了解。它将产生新的计算技术来模拟从宏观到微观长度尺度的辐射传输。开发的计算机代码将分发给国际研究界，以促进进一步的研究。这一研究计划的成果将在许多涉及辐射物理的领域得到应用，包括诊断成像、辐射防护、放射生物学和放射治疗。这项研究将有助于开发新的治疗技术，并对过去和现在的治疗产生新的见解。**

Radiotherapy is commonly used as a treatment for cancer. All forms of radiotherapy aim to maximize tumour cell kill while limiting healthy tissue radiation exposure. Despite the widespread application of radiotherapy to treat cancer, fundamental questions relating to the interactions of radiation with matter remain. Further, potential future treatment methods prompt new areas of investigation. This research program involves the development and application of sophisticated computer codes which employ the so-called 'Monte Carlo' (MC) method to model the passage of radiation through matter. These MC simulations can be used to compute dose, the energy deposited by radiation in tissue, as well as to study a wide array of questions relevant for radiotherapy treatments.*** An existing treatment to be considered is brachytherapy, in which radioactive sources are placed next to or inside a tumour (in, e.g., the prostate, breast, or eye). Widely-used dose calculation algorithms are inaccurate; a fast, accurate, and comprehensive MC dose calculation program is under development and will be used to study brachytherapy physics.***There is increasing interest in simulating radiation interactions and radiation-induced damage at the level of cellular constituents and DNA to understand the biological effects of radiation. Simulations of microscopic tissue structure including cells and their components present computational challenges; furthermore, new approaches consistent with modern quantum physics may be required at very low energies and short distance scales. New methods for performing simulations of radiation transport on multiple scales, from patient-level down to cells and cell components in tissue, will be developed. These techniques will be applied to understand patterns of energy deposition within tissue for different radiation sources, towards developing an understanding of the biological effects of radiation. These new computational approaches will also be applied to study potential future treatment techniques such as delivery of radiotherapy involving nanometre-sized devices and other targeted therapies.*** This research will advance our knowledge of the interactions of radiation with matter and radiation dosimetry. It will yield new computational techniques to simulate radiation transport from macroscopic to microscopic length scales. Computer codes developed will be disseminated to the international research community to foster further research. The results of this research program will find application in many fields involving radiation physics including diagnostic imaging, radiation protection, radiobiology, and radiation therapy. This research will contribute to the development of new treatment techniques, as well as yielding new insights into past and current treatments. **