TC-99M-LABELED NONSPECIFIC POLYCLONAL HUMAN IMMUNOGLOBULIN-G IS TAKENUP BY MALIGNANT-TUMORS

A new agent originally introduced for localizing inflammatory lesions is Tc-99m human immunoglobulin G (HIG). Recently, focal uptake of this agent was seen in malignant lesions in a limited number of patients d uring inflammation imaging studies. In this prospective clinical study , the authors aimed to evaluate the uptake of Tc-99m HIG in malignant lesions. Nineteen patients with histopathologically proven malignant t umors were studied (seven had distant metastases, the primary tumor wa s surgically removed in two). There was no evidence of inflammation or infection in any patient. The authors imaged patients at 1, 4, and 24 hours after injection. The dose was 15-20 mCi (555-740 MBq). Focal up take was detected in the primary tumor in six patients and in the meta stases in five patients, raising some question about the specificity o f Tc-99m HIG imaging for the detection of inflammation and infection.