Dosimetry and Radiobiology for Laser Induced Proton Beams

激光产生的离子束有可能用于未来的癌症治疗，因为它们可以提供紧凑，更便宜的替代来源，目前用于质子和碳离子治疗。相对于高能X射线，离子束疗法在治疗肿瘤方面具有相当大的优势，这是由于通过布拉格峰的能量的限定沉积。这个博士项目是EPSRC资助的一个大型合作项目的一部分，该项目旨在开发具有适用于未来治疗的特性的激光产生的离子束，并测试暴露于正常和肿瘤细胞中的这些光束的后果。与传统来源相比，激光产生的离子束以极高的剂量率提供辐射剂量，除了探索这种制度的放射生物学之外，博士研究的一个关键目标将是确定在这些极端条件下质子和碳剂量测定的有效方法。出于对未来临床应用的潜力，目前的实验活动，采用激光驱动源致力于开发一种方法，用于进行有意义的生物测定在激光等离子体环境中，剂量的顺序几个Gys可以在一个单一的照射。制定适当的剂量测定方法是本研究过程中面临的一个关键挑战。由于激光驱动离子源的稳定性和再现性仍然不理想，为了正确估计辐照条件，必须在每个辐照事件的过程中可靠地测量剂量，理想情况下以非侵入性方式测量。因此，我们将致力于适当的校准薄膜剂量计在特定的能量和剂量范围内的相关的激光驱动离子源。这将包括验证定制的辐射变色薄膜，以及使用丙氨酸颗粒和CR39粒子轨道探测器。除了这些相对剂量测定方法外，该项目还将测试绝对剂量测定工具（如法拉第杯和离子量热计）在激光等离子体环境中的有效性。

Laser-generated ion beams have the potential to be used for future cancer therapies as they may provide compact, less expensive alternative sources to those currently used for proton and carbon-ion therapies. Ion-beam therapies have considerable advantages for treating tumours relative to high energy X-rays due to the defined deposition of energy via a Bragg Peak. This PhD project forms part of a large, EPSRC-funded collaborative effort aimed to develop laser-generated ion beams with properties suitable for future use in therapy, and test the consequences of exposure to these beams in normal and tumour cells. Laser produced ion beams deliver radiation dose at extremely high dose-rates in comparison to conventional sources and, in addition to exploring the radiobiology of this regime, a key goal of the PhD research will be to define effective approaches for proton and carbon dosimetry under these extreme conditions. Motivated by the potential for future clinical applications, current experimental activities employing laser-driven sources are devoted to developing a methodology for carrying out meaningful biological assays in a laser-plasma environment , where doses of the order of several Gys can be delivered in a single irradiation. The development of appropriate approaches to dosimetry is a key challenge to be faced in the course of this research. Since the stability and reproducibility of laser-driven ion sources is still not ideal, for a correct estimate of the irradiation conditions, the dose must be measured reliably in the course of every irradiation event, ideally in a non-invasive manner. We will therefore devote effort to the appropriate calibration of film dosimeters in the specific energy and dose range of relevance to the laser-driven ion sources. This will include the validation of customised radio chromic films, as well as the use of alanine pellets and CR39 particle track detectors. In addition to these approaches to relative dosimetry, the project will aim to test the effectiveness in a laser-plasma environment of tools for absolute dosimetry such as Faraday cups and ion calorimeters.