PET Imaging of the Immune System Using Analog Probes

The goal of this proposal is to assess the biodistribution of 18F-Clofarabine, a new tracer developed for use in PET/CT scans. The investigator's hypothesis is this tracer will allow for imaging immune activation in patients with melanoma before and after treatment with immunotherapy. A maximum of 10 subjects are intended to be included in this study. Each subject will undergo a maximum of two 18F-Clofarabine PET/CT scans, with each visit taking up to 4 hours. The first visit will be prior to the first cycle of immunotherapy treatment, and the second scan will take place 2-4 weeks after the immunotherapy treatment has started. Prior to the PET scan an IV line will be placed. Blood pressure, heart rate, blood oxygen and ECG will be obtained. Then the 18F-Clofarabine will be injected and the PET/CT scan acquisition started. After a maximum of 120 min of scanning, subjects will undergo again blood pressure, heart rate, blood oxygen and ECG.