EP62-1LPSPMed: Used to Encapsulate Radioactive Iodine-125 Seeds Within a 3D-printed Episcleral Plaque
Overview of EP62-1LPSPMed
Master Bond EP62-1LPSPMed is an ultra-low-viscosity, two-part epoxy with a long working life that combines strong mechanical performance, broad substrate adhesion, and cryogenic stability. It also shows exceptional resistance to radiation and common medical sterilization methods, as well as biocompatibility, making it well-suited for the precision encapsulation of radioactive iodine-125 (125I) in 3D-printed episcleral plaques.
Application
Episcleral plaque brachytherapy is a standard treatment for intraocular tumors where a device containing radioactive 125I seeds is placed directly on the episclera. 125I seeds then deliver continuous, low-dose radiation directly to tumors to kill cancer cells. Although this approach minimizes damage to surrounding tissues, conventional plaques still deliver unwanted radiation to healthy tissues and often cause retinopathy or cataracts.
Recent advances in 3D printing and radioactivity painting have made it possible to tailor the tumor dose coverage to reduce lateral radiation exposure. Researchers at Canada’s Laboratoire de Biomatériaux pour l’Imagerie Médicale developed a 3D-printed plaque, where tungsten-loaded PEEK filament was used as a radiopaque polymer and shaped into an episcleral plaque with 16 cylindrical cavities (CCs) on its inner surface. These cavities acted as collimators that concentrated radioactivity from 125I to attenuate lateral emission. The authors used Master Bond EP62-1LPSPMed as a biocompatible, ultra-low-viscosity epoxy to encapsulate radioactive 125I within each cavity, ensuring stable source positioning and containment without altering the plaque geometry or radiopacity.
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