Development of real-time dosimetry methods for VHEE FLASH Radiation Therapy

癌症是一个关键的社会问题。在全球范围内，仅在2018年，就有1810万人被诊断出癌症，960万人死亡，4380万人患有癌症。目前的预测预计，到2030年，新诊断的患者将增加约2460万人，相关死亡人数将增加1300万人。自1895年发现X射线以来，X射线在癌症治疗中发挥了关键作用。众所周知，高能粒子束在进入物质并在物质中传播时会储存动能。在放射治疗中，射线的这一特性被用于肿瘤的治疗，因为沉积的能量可以破坏和杀死肿瘤细胞。不同的粒子类型被用于这一目的--光子(最常见的RT类型)、电子、中子、质子和重离子。放射治疗现在是有效的癌症治疗和控制的基本组成部分。最常用的RT方式是使用高能(6至10 MeV)光子，以及一小部分低至中能(3至25 MeV)电子束。放射治疗的主要挑战是传递给肿瘤的剂量受到周围正常组织所能承受的剂量的限制。另一方面，传统的光子放射治疗的特点是近乎指数衰减和吸收，因此在射束入口处传递最大能量，但在远离癌症靶点的距离继续沉积大量能量。能量约为8 MeV的光子光束的最大剂量在软组织深度2-3厘米处达到。放射治疗是迄今为止最具成本效益的癌症治疗方式，另外还有保存正常组织功能的优势。全球癌症控制放射治疗工作组(GTFRCC)估计，到2035年，将需要12,600兆伏级的治疗机来满足LMIC的需求(目前只有385台机器)。目的和目标。STELLA(利用直线加速器延长寿命的智能技术)项目将确定先进的X射线RTT系统的基本规格，以便在具有挑战性的环境中应用。将开发一种符合这些要求的合适的电子束加速器，结合能够提供稳健操作和模块化实施的现代原理和技术。对于加速器，将探索线性加速器(直线加速器)的模块化选择，其维护将更加简单和廉价。这些评估将包括：a)从直线加速器结构简单地分离的模块化电子枪设计的可行性，以便于维修/更换，以提高可靠性和寿命。B)新的开放式直线加速器结构解决方案，其制造成本可大大降低，并消除了对调谐柱制造的要求。C)新的紧凑型射频源为直线加速器供电，以最大限度地减小机器的物理尺寸。D)医院工程师更换更简单的交钥匙射频系统的解决方案。E)如何将高度可变的电力供应的影响降至最低并确定改进的方法。F)改进了本地控制和远程监控的模块化，以预测常见故障模式并最大限度地减少停机时间。G)RTT系统未能对官方发展援助国家的几家医院提供的数据进行统计分析的主要原因。在达累斯伯里克拉拉的调制器、速调管、射频腔和电子枪中也发现了类似的问题，可以作为这些研究的试验台。学生将与ASTEC(Stella原型技术主管)合作。

Cancer is a critical societal issue. Worldwide, in 2018 alone, 18.1 million cases were diagnosed, 9.6 million people died and 43.8 million people were living with cancer. Current projections anticipate an increase with approximatively 24,6 million newly diagnosed patients and 13 million related deaths by 2030.Ever since the discovery of X-rays in 1895, they played key role in cancer treatment. The beams of high-energy particles are known for depositing their kinetic energy when entering and propagating through matter. In radiotherapy (RT), this property of beams is used for the treatment of tumour's, since the deposited energy can damage and kill the tumour cells. Different particle types have been used for this purpose - photons (most common type of RT), electrons, neutrons, protons and heavy ions. RT is now a fundamental component of effective cancer treatment and control. The most frequently used modality of RT uses high-energy (6 to 10 MeV) photon, and in a small proportion low to intermediate energy (3 to 25 MeV) electron beams. The main challenge of RT is that the dose delivered to a tumour is limited by the dose that can be tolerated by the surrounding normal tissues.On the other hand, conventional photon RT is characterised by almost exponential attenuation and absorption, and consequently delivers the maximum energy near the beam entrance, but continues to deposit significant energy at distances beyond the cancer target. The maximum dose for photons beams with an energy of about 8 MeV, is reached at a depth of 2-3cm of soft tissue. RT is by far the most cost-effective modality for cancer treatment with the added advantage of conserving normal tissue function. The Global Task Force on Radiotherapy for Cancer Control (GTFRCC) estimated that 12,600 megavolt-class treatment machines will be needed to meet demand in LMICs by 2035 (there are currently only 385 machines) .Aims and Objectives.The STELLA (Smart Technologies to Extend Lives with Linear Accelerators) project will identify the fundamental specifications for an advanced X-ray RTT system for application in the challenging environments. A suitable electron-beam accelerator will be developed which matches these requirements, incorporating modern principles and technologies which are able to provide robust operation and modularized implementation.For the accelerator, modular options for the linear accelerator (linac) will be explored, which will be simpler and cheaper to maintain. These will include assessments of; a) The feasibility of a modular electron gun design to be simply separated from the linac structure for easy servicing/replacement to increase reliability and lifetime. b) Novel open linac structure solutions which could be substantially cheaper to manufacture and remove requirement for tuning post manufacturing. c) A new compact RF sources to power the linac, to minimise the physical size of the machine. d) Solutions for turn-key RF systems that is simpler for hospital engineers to replace. e) Ways to minimise the impact of highly variable electricity supply and determine improved methodologies. f) Improved modularity for local control and remote monitoring to predict common failure modes and minimise down time. g) The main causes of failure in RTT systems to perform statistical analysis of data provided by several hospitals in ODA countries. Similar issues are found in the Modulators, Klystrons, RF cavities and electron guns in CLARA at Daresbury and it can be used as a test bed for these studies. The student will work in collaboration with by ASTeC (technical lead for STELLA prototyping).