Primary lung cancer: biodistribution and dosimetry of two In-111-labeled monoclonal antibodies.

This study was undertaken to measure the biokinetics and organ dosimetry of indium-111-labeled monoclonal antibodies (MoAbs) with a whole-body gamma camera imaging technique. Twenty patients with primary lung cancer were studied with two different MoAb agents (anti-carcinoembryonic antigen ZCEO25 and antiadenocarcinoma LA20207). Imaging was performed at 1, 24, 72, and 144 hours after injection. Scintigraphic whole-body retention was verified by means of comparison with the results from in vitro counting of excreta. Organ retention was verified in an abdominal phantom. The MoAb cleared slowly from the heart and lungs, the brain and spleen showed no clearance, and the liver showed increased activity over the 6-day period. Dosimetry for ZCE025 showed a dose to the liver of 1.3 rad/mCi (0.36 mGy/MBq); heart, 1.5 rad/mCi (0.40 mGy/MBq); spleen, 1.1 rad/mCi (0.29 mGy/MBq); total body, 0.49 rad/mCi (0.13 mGy/MBq); and testes, 0.39 rad/mCi (0.11 mGy/MBq). The dosimetry for LA20207 was similar.