High resolution dosimetric detector for synchrotron microbeam cancer therapy

最近在萨斯卡通的加拿大光源（CLS）的生物医学成像和治疗（BMIT）光束线的可用性是一个真正的例外和独特的机会，进行研究，在生物医学技术的整体目标领域的影响。在这一战略拨款期间，我们建议开发一种高分辨率剂量检测器，用于监测微束放射治疗（MRT）中的高剂量分布。微束放射治疗是基于用强同步加速器产生的X射线的微平面阵列照射肿瘤。X射线束的薄平面切片的平行阵列的照射使包括中枢神经系统在内的正常组织免于损伤，并且优先损伤肿瘤。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源的可用性-因此在加拿大有特殊和独特的机会。应用MRT的最大问题之一是同步加速器产生的光束中的高剂量分布的测量，因为剂量很大并且在微米的距离上变化。因此，需要高空间分辨率、高动态范围剂量测定检测器以能够执行MRT。我们提出了一种新的高分辨率剂量检测板，这是基于转换的稀土（RE）离子在玻璃或玻璃陶瓷板的另一种氧化态的入射高剂量辐射。转换量取决于剂量，并且高度局限于入射辐射区域。从新的氧化态（适当的激发后）的稀土离子的荧光发射可以很容易地区分从未转换的离子。将使用荧光共聚焦成像（使用过滤器去除未转化RE离子的发射）来获得剂量分布。此外，该研究将旨在开发可重复使用的剂量板，并将优化RE掺杂板介质，响应和读出光学系统，以实现高分辨率测量。该战略项目对加拿大有直接的巨大健康利益，使用加拿大同步加速器，并培训HQP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.