Successful imaging or therapy with radiolabeled Mabs depends not only on the concentration of the Mab at the targeted site but on clearance rates from normal tissues relative to that from the tumor. Imaging studies in humans have shown that maximum concentrations of Mabs at the tumor site are attainable within 24 h, but several more days are required before the concentration of the radiolabeled Mab in the circulation decreases to levels low enough for successful ...
