Internal Pair Production of 90Y Permits Hepatic Localization of Microspheres Using Routine PET: Proof of Concept

Radioembolization with Y-90 microspheres represents a novel transarterial radiation treatment for liver tumors. The purpose of this pilot study was to evaluate the findings of postimplantation PET/CT of Y-90 glass microspheres. Methods: Three patients with hepatocellular carcinoma and 2 patients with liver metastases (1 neuroendocrine, 1 colorectal) underwent PET/CT after radioembolization. Four patients underwent imaging at 1 mo to assess response and confirm PET/CT findings; 1 patient underwent PET/CT at 4 d after Y-90 implantation. Patients were followed for adverse events. Results: Standard PET/CT enabled the localization of Y-90 glass microspheres for all patients. None of the patients experienced adverse events related to nontarget deposition. Conclusion: Standard PET/CT may be used to assess the localization of Y-90 glass microspheres. This approach provides a simple, rapid, and universally applicable method of confirming microsphere deposition. With further validation, this technique may potentially become the standard of care for confirming microsphere distribution.