A novel 3D printing method for a notched eye plaque "dummy" for uveal melanoma brachytherapy

Suture preplacement by the ocular oncology surgeon is a critical step before inserting a radioactive plaque for ocular melanoma brachytherapy. We report on a novel 3D-printing method to create a custom "dummy" plaque applicator for the 22 mm notched gold plaque using in-house 3D-printing.

A computer-aided design (CAD) file was created replicating a heavily used gold plaque that no longer has a satisfactory "dummy" plaque. The file was exported as a 3D file (surface tessellation language, STL) and prepared using Formlabs' PreForm print software. The 3D-printed dummies were oriented on the printer to have no cups or supports on the surfaces that would come in contact with the patient's external sclera. The dummies were printed in FormLabs BioMed Clear V1 on a Formlabs Form-3 3D printer. Postprinting, the dummies were processed in isopropyl alcohol and cured according to manufacturer instructions. They were polished utilizing a rotary tool to improve transparency. Chemical and sterilization cycle tests were performed to ensure dummy integrity.

Four "dummy" plaques were printed. The 3D-printed "dummy" dimensions were verified to be within 0.5-mm of the notched plaque using digital calipers. The polishing process created acceptable light opacity for the eye plaque procedure in the operating room. No impactful discoloration or material change was observed during the chemical and sterilization cycle tests performed.

3D printing can produce custom eye plaque dummies using transparent, biocompatible, chemically inert materials suitable for human use. This capability introduces an additional layer of patient-specific hygienics.