(Sunday, 7/12/2020) [Eastern Time (GMT-4)]
Room: AAPM ePoster Library
Purpose: To document, quantify, and correlate the treatment of choroidal melanoma to clinical outcomes and radiobiological dosimetry.
Methods: Data from 157 patients treated from 2014 to 2018 with LDR brachytherapy using COMS eye plaques and Iodine-125 seeds were used. The seed activities were chosen to deliver 85 Gy to the tumor apex or to a prescription point (if the apex < 5mm) at 1.48 cGy/min dose rate. The plaque sizes were 10, 12, 14, 16, 18, 20, and 22 mm including notched or deep notched. The plaques were modeled in Varian BrachyVision version 11.6 (Varian Medical Systems) with seed coordinates from the AAPM TG-129. Treatment planning calculations used TG-43 protocol and did not consider plaque heterogeneities, seed carrier attenuation, or special collimation protecting the optic nerve. Point dose data were extracted for the apex, prescription point, sclera, opposite retina, lens, macula, and optic disk. Radiobiological dosimetry were calculated using appropriate a/ß values. The population average radiobiological dosimetry were reported along with clinical results after timely follow-ups.
Results: Prior to treatment 89.17% of patients reported vision acuity >20/200 and 10.83% had visual acuity of
Conclusion: In spite of the small patient population and short term follow up, it is of interest to correlate the radiation induced effects and create a guideline for the improvement of the treatment.
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