Positron-Scanning with Copper-64 in the Diagnosis of Intracranial Lesions

Copper versenate injected intravenously in man achieves within 2 hours concentrations in metastatic tumors about 9 times and in more rapidly growing gliomas about 5 times those in normal brain. Concentrations of copper in muscle rise steadily whereas those in tumor and normal brain fall. Copper scanning, best carried out within an hour of injection, has detected about 55 per cent of a random series of intracranial tumors. In the same patients arsenic scans detected 76% of the tumors. However, some tumors were detected by copper in which the arsenic failed. Vascular lesions of the brain are less likely to yield a positive scan with copper than with arsenic. About 5% of an intravenously injected dose of copper versonate is excreted in the urine. The rest largely undergoes physical decay of its activity before excretion occurs. The Cu64 activity injected for a diagnostic scan gives a whole-body radiation dosage of 0.33 rad, which is about the weekly permissible dose for personnel constantly exposed to radiation. Hence, this diagnostic maneuver may be repeated several times with impunity.