High Reliability, Modular Radiotherapy Treatment Linac for cancer care in Developing Countries

目前，非洲只有不到10%的能力为癌症患者提供放射治疗。该项目的参与者正在与英国和全球合作者（如CERN和国际癌症专家团（ICEC））合作，在非洲具有挑战性的环境中开发医疗直线加速器解决方案。要解决的关键因素是放射治疗系统直线加速器中组件的寿命、服务和维修。这个项目旨在通过改变设计来解决这些因素，除了实现模块化的设计approaches.During以前的一个项目，我们研究了使用射频脉冲调制栅极枪注入电子束到射频结构，以增加捕获。该项目的结果表明，它可以提供几乎100%的捕获和提供非常窄的能量分布的光束（典型的放射治疗系统只能捕获50%的光束）。然而，最近的研究表明，使用栅极会使阴极寿命缩短三倍。研究还表明，通过在较低的梯度下操作直线加速器的第一单元，可以提高直线加速器的效率，从而实现90%的捕获，使用方便的DC脉冲调制枪，只有25%的电子在低能尾部。我们认为，这种效应是由于速度聚束，并要求资金进一步研究这一点，试图达到100%的捕获没有电子的尾巴。这种方法可以允许非常长的使用寿命，几乎不需要维护。模块化设计将提高系统发生故障时的修复能力。

Currently Africa has less than 10% of the required capacity to deliver radiotherapy to cancer patients. The participants in this project are working with UK and global collaborators, such as CERN and the International Cancer Expert Corps (ICEC), to develop medical linac solutions in challenging environments in Africa. The key factors to address are the lifetime, service and repair of components in the linac of the radiotherapy system. This project aims to address these factors by making changes to the design in addition to implement the modular design approach.During a previous project we investigated the use of RF pulse modulated gridded guns to inject bunches of electron beams into the RF structure to increase capture. The results of the project demonstrated that it's possible to provide almost 100% capture and deliver the beam with a very narrow energy spread (typical radiotherapy systems are only able to capture 50% of the beam). However recent studies have suggested the use of the grid reduces the cathode lifetime by a factor of three. The studies also demonstrated that the linac efficiency can be improved by operating first cell of linac at lower gradient enabling 90% capture, with only 25% of electrons in the low energy tail using convenient DC pulse modulated guns. We believe that this effect is due to velocity bunching and request funds to further study this to attempt to reach 100% capture with no electrons in the tail. Such an approach could allow very long lifetimes with little maintenance. Modular design will improve the capability to repair when the system does fail.