Objectives: Accurate target definition, treatment planning and delivery increases local tumor control for radiotherapy by minimizing collateral damage. To achieve this goal for uveal melanoma (UM), tantalum fiducial markers (TFMs) were previously introduced in proton and photon beam radiotherapy. However, TFMs cause pronounced scattering effects in imaging that make the delineation of small tumors difficult. The aim of this study was to evaluate silicone fiducial markers (SFMs) for the guiding of stereotactic radiosurgery (SRS) for UM.Methods: In this retrospective interventional pilot case series, three patients with small UMs 3 mm or less in tumor thickness and ≤10 mm in largest basal diameter received silicone fiducial markers. The fiducial markers were punched out (3 mm) from conventional silicone encircling bands for buckle surgery. The markers were sutured onto the sclera at the tumor margins according to the use of TFMs. MRI and CT images were used for the localization of the tumor and the markers before robotic-guided SRS.Results: The silicone fiducial markers were punched out easily from the original band, better to handle than TFMs and easy to suture onto the sclera. They could be visualized in both MRI and CT, but were more visible in CT. In the absence of scattering effects, both the markers and thus the tumor boundaries could be clearly delineated.Conclusions: This is the first report that introduces fiducial markers intraoperatively shaped from conventional silicone encircling bands usually used for retinal detachment surgery. The SFMs allow more accurate tumor delineation, resulting in the more precise planning and administration of SRS when compared to TFMs. This simple modification has a major impact on a well-known treatment approach.
目的：通过精确的靶区定义、治疗计划与实施，最大限度减少附带损伤，从而提高放射治疗的局部肿瘤控制率。为实现葡萄膜黑色素瘤（UM）的这一治疗目标，既往已在质子束和光子束放疗中引入钽基准标记物（TFMs）。然而，TFMs在影像中会产生明显的散射效应，导致小肿瘤的轮廓勾画困难。本研究旨在评估硅胶基准标记物（SFMs）在UM立体定向放射外科（SRS）治疗中的引导作用。 方法：本回顾性介入性先导病例系列研究纳入3例肿瘤厚度≤3mm、最大基底直径≤10mm的小型UM患者。基准标记物从用于巩膜扣带术的常规硅胶环扎带上冲切（3mm）制成。参照TFMs的使用方法，将标记物缝合固定于肿瘤边缘的巩膜表面。在机器人引导SRS治疗前，采用MRI和CT影像进行肿瘤及标记物定位。 结果：硅胶基准标记物易于从原环扎带上冲切成型，比TFMs更易操作且便于缝合至巩膜。标记物在MRI和CT影像中均可见，但在CT中显影更清晰。由于无散射效应干扰，标记物及肿瘤边界均可清晰勾画。 结论：本研究首次报道术中利用视网膜脱离手术常规硅胶环扎带塑形制备基准标记物。与TFMs相比，SFMs能实现更精确的肿瘤轮廓勾画，从而使SRS治疗计划与实施更为精准。这一简易改良对成熟治疗方案具有重要影响。
Silicone Fiducial Markers Improve Precision in Uveal Melanoma Radiation Therapy
肿瘤(癌症)患者之家