PET scanning of ocular melanomas after proton therapy

Abstract

In an effort to understand the possibility of using PET as a tool for dose verification after proton therapy in ocular melanomas, a Lucite phantom was irradiated at the proton therapy facility at TRIUMF with a raw and spread-out Bragg peak of 74 MeV protons and scanned in two different PET scanners at UBC. A tantalum clip, used as a marker during patient treatment, was attached to the phantom. Irradiation with the raw Bragg peak results in a different activation profile than with the spread-out Bragg peak. The difference is easily observable in the PET scan. In addition, one patient treated for choroidal melanoma was scanned. In the patient scan the activity in the irradiated tumor is clearly visible. A FLUKA simulation of the facility is currently being validated against experimental measurements.