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

该项目旨在改进眼部肿瘤的斑块治疗，考虑到更准确的诊断。近距离放射治疗是眼内肿瘤最常用的治疗方式。它的成功高度依赖于应用于肿瘤和危险器官的准确剂量分布。作为多特蒙德工业大学DFG项目EI869/1-1的一项成果，通过蒙特卡洛模拟和测量获得了所有常用Ru-106涂层眼斑的非常精确的空间剂量分布知识。此外，与埃森大学的合作产生了一种新的非常紧凑的ABI核素斑块设计(使用放射性核素Ru-106和I-125的组合的斑块)。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)，同时保留了尽可能多的正常组织。这种斑块的确切剂量分布也将被确定。虽然获得的剂量测量精度超过了当前的标准，但只有结合更精确的临床诊断才能优化治疗结果。全光学相机的引入将加强和改进诊断特征的可能性。这款相机将有助于从眼底镜下三维重建球茎内部几何形状，以及感兴趣的结构的详细视图，如肿瘤和乳头。这将提供肿瘤相对于斑块位置的位置和拓扑的精确确定，并且首次单独使用光学方法。在这样的眼底图中，斑块的位置将用固定在斑块边缘的LED来标记，并通过封闭和手术后可见。该项目将产生一个结合剂量测量和诊断数据的治疗计划系统。这些成果将与全球领先的眼癌治疗中心之一的埃森大学合作取得。计划在埃森进行一项单独的临床试验，以确定可行性。联合考虑剂量学和诊断数据将有助于更好地使安全裕度适应实际临床情况。在保持肿瘤控制率的同时，将讨论降低剂量的可能性，目的是将副作用降至最低。

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.