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

癌症是一个严重的社会问题。仅在2018年，全球就有1810万例癌症确诊病例，960万人死亡，4380万人患有癌症。目前的预测预计，到2030年，新诊断患者将增加约2460万，相关死亡人数将增加1300万。自从1895年发现x射线以来，它们在癌症治疗中发挥了关键作用。高能粒子束在进入物质并通过物质传播时以其动能沉积而闻名。在放射治疗（RT）中，光束的这种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。不同类型的粒子被用于这一目的——光子（最常见的RT类型）、电子、中子、质子和重离子。放疗现在是有效的癌症治疗和控制的基本组成部分。RT最常用的方式是使用高能（6至10 MeV）光子，以及一小部分低至中能量（3至25 MeV）电子束。放射治疗的主要挑战是，给肿瘤的剂量受到周围正常组织可耐受剂量的限制。另一方面，传统光子RT的特点是几乎呈指数衰减和吸收，因此在光束入口附近提供最大能量，但在癌症目标以外的距离继续沉积大量能量。能量约为8mev的光子束的最大剂量在软组织的2-3cm深度达到。放疗是迄今为止最具成本效益的癌症治疗方式，具有保留正常组织功能的额外优势。全球癌症控制放疗工作组（GTFRCC）估计，到2035年，将需要12,600台兆伏特级治疗机来满足中低收入国家的需求（目前只有385台机器）。目的和目标。STELLA（通过线性加速器延长使用寿命的智能技术）项目将确定先进x射线RTT系统的基本规范，用于具有挑战性的环境。一种合适的电子束加速器将开发符合这些要求，结合现代原理和技术，能够提供稳健的操作和模块化的实施。对于加速器，将探索线性加速器（直线加速器）的模块化选项，这将更简单，更便宜的维护。这些评估将包括：a)模块化电子枪设计的可行性，简单地从直线结构中分离出来，便于维修/更换，以提高可靠性和使用寿命。b)新颖的开放式直线结构解决方案，可以大大降低制造成本，并消除对调谐后制造的要求。c)一个新的紧凑型射频源为直线加速器供电，以尽量减少机器的物理尺寸。d)交钥匙射频系统的解决方案，使医院工程师更容易更换。e)如何尽量减少多变的电力供应的影响，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，以预测常见的故障模式并最大限度地减少停机时间。g) RTT系统无法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。在达斯伯里CLARA的调制器、速调管、射频腔和电子枪中也发现了类似的问题，它可以作为这些研究的试验台。该学生将与ASTeC （STELLA原型的技术领导）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).