Lead contact lens for crystalline lens shielding in electron therapy for eyelid tumors.

In radiotherapy for eyelid tumors, a sufficient dose is required in the target tissue while preserving the crystalline lens. A I-mm thick, 20-mm diameter lead contact lens was prepared for crystalline lens protection. The lens was coated with an acrylic polymer and weighted 5.5 g. Six MeV electron therapy was scheduled using a 10 mm bolus on the eyelid. A simulation experiment proved that 0.78 +/- 0.04 percent of the maximal eyelid dose was given at the crystalline lens portion. A total of 14 eyelids in eight patients with cutaneous lymphoma, angiosarcoma, or basal cell carcinoma were treated with the contact lens. No cataract was found after irradiation over an average period of 24.3 months. The combination of the lead contact lens, bolus, and 6 MeV electron beam was a simple procedure and provided adequate dose distribution in the treatment of various eyelid tumors.