Optimization studies of eye tumor - brachytherapy taking into account the position and dimensions of the tumor and the design, dosimetry and positioning of the radioactive eye plaque

该项目旨在改进眼内肿瘤的眼斑治疗，考虑到更精确的诊断。近距离放射治疗是眼内肿瘤最常用的治疗方式。作为德国多特蒙德工业大学EI 869/1-1 DFG项目的一项成果，我们通过蒙特卡罗模拟和测量，获得了所有常用Ru-106涂层眼斑的空间剂量分布的精确知识。此外，与Universitätsklinikum埃森大学的合作产生了一种新的、非常紧凑的双核素斑块设计（一种使用放射性核素Ru-106和I-125组合的斑块）。与Ru-106斑块相比，双核素斑块扩大了可治疗肿瘤大小的范围（高达7至10 mm高），同时尽可能保留正常组织。虽然获得的剂量精确度超过了目前的标准，但只有与更精确的临床诊断相结合才能优化治疗效果。全光摄像机的引入将增强和提高诊断功能的可能性。这台相机将有助于从眼底镜三维重建内部球的几何形状，沿着感兴趣的结构的详细视图，如肿瘤和乳头。这将提供与斑块位置相关的肿瘤位置和拓扑结构的确定，精确地，并且首次仅使用光学方法。在这样的眼底视图中，斑块的位置将被固定在斑块边缘的LED标记，并通过巩膜切除术和手术后可见。该项目将产生一个结合剂量测定和诊断数据的治疗计划系统。这些结果将与世界领先的眼癌治疗中心之一的埃森大学合作实现。计划在埃森进行一项单独的临床试验以确定其可行性。剂量测定和诊断数据的综合考虑应有助于更好地使安全裕度适应实际临床情况。将讨论剂量递减的可能性，同时提高肿瘤控制率，目的是最大限度地减少副作用。

The project is aimed at an improvement of the ophthalmic plaque therapy ofocular tumors, taking a more precise diagnostics into consideration.Brachytherapy is the most frequently used treatment modality forintraocular tumors. Its success highly depends on the exact dosedistribution applied to the tumor and to organs at risk.As an achievement of the DFG project EI869/1-1 at Technical UniversityDortmund, a very precise knowledge of spatial dose distributions of allcommonly used Ru-106 coated eye-plaques was gained by Monte Carlosimulations and measurements. Furthermore, a collaboration with theUniversitätsklinikum Essen resulted in a new and very compact design for abi-nuclide plaque (a plaque using a combination of the radionuclidesRu-106 and I-125). Compared to Ru-106 plaques bi-nuclide plaques extendthe range of treatable tumor sizes (up to 7 to 10 mm height), sparing asmuch normal tissue as possible at the same time. The exact dosedistribution for this type of plaque will be determined as well.While the gained dosimetric precision exceeds current standards, only acombination with a more precise clinical diagnostics will optimizetherapeutic outcomes. The introduction of a plenoptic camera shall enhanceand improve the possibilities of diagnostic features. This camera willfacilitate the three-dimensional reconstruction of the interior bulbusgeometry from a funduscopy, along with a detailed view of interestingstructures, such as the tumor and papilla. This will offer thedetermination of the position and topology of the tumor in relation toplaque position, precisely and, for the first time, by sole usage of anoptical method. In such a fundus view, the plaque position will be markedwith LEDs fixed to the rim of the plaque and visible through the scleraduring and after surgery.This project shall result in a treatment planning system that combines thedosimetric anddiagnostic data. These results shall be achieved in collaboration with theUniversitätsklinikum Essen, one of the worldwide leading centers for thetreatment of eye cancer. A separate clinical trial in Essen is planned toascertain feasibility. Combined consideration of dosimetric and diagnosticdata shall help to better adapt safety margins to the actual clinicalsituation. The possibility for a dose de-escalation, while maintainingtumor control rate, will be discussed with the objective to minimize sideeffects.