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

放射疗法通常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死肿瘤细胞，同时限制健康组织的辐射暴露。 尽管放射疗法广泛应用于治疗癌症，但与辐射与物质相互作用有关的基本问题仍然存在。 此外，未来潜在的治疗方法促进了新的研究领域。 该研究计划涉及复杂计算机代码的开发和应用，这些代码采用所谓的“蒙特卡罗”（MC）方法来模拟辐射穿过物质的过程。 这些 MC 模拟可用于计算剂量、辐射在组织中沉积的能量，以及研究与放射治疗相关的各种问题。*** 要考虑的现有治疗方法是近距离放射治疗，其中将放射源放置在肿瘤旁边或肿瘤内部（例如，前列腺、乳房或眼睛中）。 广泛使用的剂量计算算法不准确；快速、准确且全面的 MC 剂量计算程序正在开发中，将用于研究近距离放射治疗物理学。***人们越来越有兴趣在细胞成分和 DNA 水平上模拟辐射相互作用和辐射引起的损伤，以了解辐射的生物效应。 包括细胞及其成分在内的微观组织结构的模拟提出了计算挑战；此外，在非常低的能量和短距离尺度下可能需要符合现代量子物理学的新方法。 将开发从患者层面到组织中的细胞和细胞成分的多个尺度上进行辐射传输模拟的新方法。 这些技术将用于了解不同辐射源的组织内能量沉积模式，以加深对辐射生物效应的理解。 这些新的计算方法还将应用于研究未来潜在的治疗技术，例如涉及纳米尺寸设备的放射治疗和其他靶向治疗。*** 这项研究将增进我们对辐射与物质相互作用和辐射剂量测定的了解。 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。 该研究项目的成果将在涉及辐射物理学的许多领域得到应用，包括诊断成像、辐射防护、放射生物学和放射治疗。 这项研究将有助于新治疗技术的开发，并对过去和当前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. **