Imaging of Brain Tumors with Copper-64 Chloride: Early Experience and Results

Objectives: To conduct the first investigational study that is aimed at evaluating the ability of the simple salt (CuCl2)-Cu-64 to diagnose cerebral tumors in patients affected by glioblastoma multiforme (GBM). Methods: Nineteen patients with a documented history and radiologic evidence of brain tumors were enrolled in the study. Eighteen patients were diagnosed with GBM, and one patient was diagnosed with grade II astrocytoma. After initial cerebral magnetic resonance imaging (MRI), patients were administered with (CuCl2)-Cu-64 (13 MBq/kg) and brain positron emission tomography (PET)/computed tomography (CT) imaging was performed at 1, 3, and 24 hours after administration. Standardized uptake values (SUVs) were calculated and used to figure out the pharmacokinetic profile of the tracer. Absorbed radiation doses were estimated using OLINDA/EXM. Results: Copper-64 chloride clearly visualized brain cancerous lesions within 1 hour after injection, with stable retention of radioactivity at 3 and 24 hours. Excellent agreement was found between PET/CT and MRI. No uptake of the tracer was observed in low-grade astrocytoma. The agent cleared rapidly from the blood and was mostly excreted through the liver, without significant kidney washout. Analysis of time variation of SUVmax values showed persistent uptake in malignant tissues with a slight increase of radioactive concentration at 24 hours. Conclusions: Copper-64 chloride has favorable biological properties for brain imaging and warrants further investigation as a diagnostic tracer for GBM.