High resolution dosimetric detector for synchrotron microbeam cancer therapy

生物医学成像和治疗(BMIT)光束线最近在萨斯卡通的加拿大光源(CLS)上上市，这是一个真正特殊和独特的机会，可以开展对生物医学技术总体目标领域产生影响的研究。在这一战略拨款期间，我们建议开发一种高分辨率剂量探测器，用于监测微束放射治疗(MRT)的高剂量分布。微束放射治疗是基于用强同步辐射产生的X射线的微平面阵列照射肿瘤。用平行的X射线薄层平面层进行照射，可以避免对包括中枢神经系统在内的正常组织进行照射，并优先损害肿瘤。MRT已被证明在癌症治疗中有很大的好处，并且依赖于同步加速器的可用性-因此在加拿大有特殊和独特的机会。应用MRT的最大问题之一是测量同步加速器产生的束流中的高剂量分布，因为剂量很大，并且随着微米的距离而变化。因此，需要一个高空间分辨率、高动态范围的剂量学探测器来执行MRT。我们提出了一种新型的高分辨率剂量探测器板，它是基于玻璃或微晶玻璃板中的稀土离子在入射的高剂量辐射下转变为另一种氧化态。转换量取决于剂量，并且高度局限于入射辐射区域。稀土离子的新氧化态(经过适当激发后)的荧光发射可以很容易地与未转化离子的荧光发射区分开来。荧光共聚焦成像将被用来获得剂量分布，该成像带有滤光片来去除未转化的稀土离子的发射。此外，这项研究的目标是开发可重复使用的剂量测定板，并将优化稀土掺杂板的介质、响应和读出光学系统，以进行高分辨率测量。该战略项目直接给加拿大带来了巨大的健康益处，使用了加拿大同步加速器，并培训了HQP的跨学科实验技能。

The recent availability of the Biomedical Imaging and Therapy (BMIT) beam line at the Canadian Light Source (CLS) in Saskatoon is a truly exceptional and a unique opportunity to carry out research that has impact in the overall target area of biomedical technologies. During this strategic grant we propose to develop a high resolution dosimetric detector for use in monitoring the high dose profile in Microbeam Radiation Therapy (MRT). Microbeam Radiation Therapy is based on the irradiation of tumors with microplanar arrays of intense synchrotron-generated x-rays. Irradiation with parallel arrays of thin, planar slices of x-ray beams spares the normal tissue, including the central nervous system, and preferentially damages tumors. MRT has been shown to be of great benefit in cancer therapy, and relies on the availability of a synchrotron source - hence the exceptional and unique opportunity in Canada. One of the biggest problems in applying MRT is the measurement of the high dose profile in the synchrotron generated beam, since the dose is large and varies over distances of micrometers. Thus, a high spatial resolution, high dynamic range dosimetric detector is needed to be able to perform MRT. We propose a novel high resolution dosimetric detector plate which is based on the conversion of rare-earth (RE) ions in a glass or glass-ceramic plate to another oxidation state by the incident high dose radiation. The converted amount depends on the dose and is highly localized to the incident radiation region. The fluorescence emission from the new oxidation state (after suitable excitation) of the RE ion can be easily distinguished from that from unconverted ions. Fluoroscopic confocal imaging, with filters to remove the emission from unconverted RE ions, will be used to obtain the dose distribution. Further, the research will aim to develop reusable dosimetric plates, and will optimize the RE-doped plate medium, response and the read-out optics for high resolution measurements. The strategic project has direct enormous health benefits to Canada, uses the Canadian synchrotron, and trains HQP in interdisciplinary experimental skills.