Author: Andrew Lukban, Kiran Pant, Charlotte Elizabeth Read, Ren-Dih Sheu 👨🔬
Affiliation: Icahn School of Medicine at Mount Sinai, Mount Sinai Health System, Icahn School of Medicine at Mount Sinai, Department of Radiation Oncology 🌍
Purpose: Ophthalmic brachytherapy relies on Collaborative Ocular Melanoma Study (COMS) protocol and its updated reports. Their reports provide standardized methods for eye plaque brachytherapy, describing gold-alloy-backed plaques loaded with a Silastic insert and LDR seeds. However, the Silastic insert introduces dose uncertainty; thus, the seeds can instead be glued directly to the plaque with or without a gold template insert using dental resin. While directly gluing the seeds decreases dose uncertainty, the gluing process is tedious, lengthy, and error-prone, especially when no gold template is available. The purpose of our study is to reduce radiation worker exposure time by creating a seed carrier template from the dental resin.
Methods: The DuraLay Inlay Pattern Resin powder is mixed with the liquid (3:1), stirred to a moldable consistency, and placed in an empty eye plaque. This resin is flattened and evenly distributed throughout the eye plaque backing. We tried two distinct techniques: (1) engrave the hardened resin and (2) stamp the resin while still moldable with the printed seed loading pattern. Both processes can be performed without any radiation exposure. Lastly, the seeds are loaded into the resin carrier, and a thin resin layer is added to hold the seeds in place. No additional material was introduced in this process.
Results: Stamping moldable resin was faster and less tedious than engraving hardened resin. A resin carrier template with COMS seed placement geometry was created using a 3D-printed precise stamp. Compared to free-hand gluing, this method reduced the radiation worker’s exposure time from >30-45 min./eye plaque to <10 min./eye plaque.
Conclusion: The resin carrier template promotes ALARA techniques by reducing the radiation worker’s exposure time by at least 1/3, depending on the eye plaque size and seed geometry. Additionally, the resin carrier template improves seed placement by closely matching planning placement geometry.