利用晶体透镜聚焦高能电子束以应用于放射治疗
Focusing of high energy electron beam using crystal lenses for applications in radiotherapy
AI总结：
本文探讨了利用弯曲硅晶体透镜替代四极磁铁聚焦极高能电子束用于放射治疗的可行性，通过Geant4模拟验证了其聚焦能力，并提出了增强聚焦强度的技术要求与替代方案。
摘要：
两种主要的放射治疗方法中，要么在束流产生和操作方面较为简化，但这会损害组织中的能量沉积曲线（光子治疗），要么需要庞大的加速器设施和复杂的束流传输系统，以提供良好的能量沉积曲线形状（强子治疗）。通过将极高能电子束（束能量在几百 MeV 量级）聚焦于肿瘤病灶区域，有可能同时实现这两种方法的优点，例如设备成本低、束流易于产生以及组织中合适的能量沉积曲线形状。然而，束流聚焦通常使用四极磁铁完成，这使得束流传输系统从工程角度来看复杂且具有挑战性。本文探讨了一种替代方案的可行性，即利用出口面形状合适的弯曲硅晶体来进行聚焦。这种晶体透镜可以是非常轻的物体（质量在克量级），从而使得放射治疗设施的束流传输系统更加简单。作为这项可行性研究的结果，在 Geant4 中准备了一个具有仿形出口的弯曲硅晶体的模拟。从模拟中获得的结果证明了这种仿形晶体的聚焦能力。然而，该晶体的聚焦强度不够强。为实现聚焦效率的提升所需的技术要求已被识别和理解。此外，还提出了在使用仿形晶体的同时提供更强聚焦的替代方案。
英文摘要：
The two dominant radiotherapy methods are either simplified in terms of beam generation and handling, which compromises the energy deposition curve in tissues (photon therapy), or require extensive accelerator facilities and complex beam delivery systems to provide a favorable shape of the energy deposition curve (hadron therapy). The advantages of both of these methods, such as the low cost of the apparatus, ease of beam generation, and a suitable shape of the energy deposition curve in tissues, can potentially be achieved by using a very high-energy electron beam (beam energy in the order of a few hundreds of MeV) focused on the area of the tumor lesion. However, focusing of the beam is usually done with the use of quadrupole magnets which makes the beam delivery system complex and challenging from the engineering point of view. In this thesis, the feasibility of an alternative solution is explored, where focusing is performed by a bent silicon crystal with an appropriate shape of its exit face. Such a crystal lens can be a very light object (mass in the order of grams), allowing for much simpler beam delivery systems of radiotherapy facilities. As a result of this feasibility study, a simulation of a bent silicon crystal with profiled exit was prepared in Geant4. The outcome obtained from the simulation proved the focusing ability of such profiled crystal. However, the focusing strength of the crystal is not strong enough. Technical requirements needed to enable an improvement in focusing efficiency were identified and understood. Moreover, alternative solutions providing stronger focusing while using profiled crystals were proposed.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
