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

点击翻译按钮获取中文摘要

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.