PET/MR Guided Localization for Radio-guided Surgery

2672 Objectives 1. Review the existing literature on radio-guided surgery using conventional nuclear medicine and PET radiopharmaceuticals, gamma cameras and PET/CT scanners. 2. Learn about a new technique using PET/MR in the pre-operative localization of lesions prior to radio-guided surgery.\nBackground:\nRadiopharmaceuticals have been used in conjunction with gamma cameras and PET scanners to localize tumor deposits prior to radio-guided surgery using intra-operative probes, often assisted by portable cameras. One disadvantage of PET/CT scanners is that pre-operative lesion localization may require multiple CT acquisitions, thus increasing radiation exposure to the patient. This exhibit will briefly review conventional techniques to localize non-palpable tumor deposits before surgery using nuclear medicine techniques, and will demonstrate in detail a new method of FDG PET/MR-guided pre-operative lesion localization prior to radio-guided surgery.\nA major focus of this review will be on case examples of patients with non-palpable subcutaneous FDG-avid tumor deposits for which surgical resection is the gold standard for management. After confirming uptake on whole-body PET/CT, patients are referred to the PET/MR Department on the day of surgery. FDG is injected and lesions are imaged on a Siemens Biograph mMR PET/MR scanner using conventional static PET and STIR MR sequences. A vitamin E marker is used in conjunction with an FDG point source to mark the tumor location on the skin, and the best orientation for surgical dissection and patient positioning is reviewed. A PET probe is used intra-operatively to assist in identification of tumor deposits.\n Methods - Results -\nConclusions: -