DETECTION OF DEEP VENOUS THROMBI AND PULMONARY EMBOLUS WITH TECHNETIUM-99M-DD-3B6 22 ANTIFIBRIN MONOCLONAL-ANTIBODY FAB' FRAGMENT/

Technetium-99m-labeled anti-fibrin DD-3B6/22 Fab' monoclonal antibody fragments, which specifically target human crosslinked fibrin with hig h affinity, were evaluated in humans for safety and their capacity to detect deep vein thrombi and pulmonary embolism. Methods: Twenty patie nts with proven deep-vein thrombosis, documented by contrast venograph y, or venous duplex scan, were injected with a 600 MBq (0.5 mg) dose o f antibody. Planar images of the lower limbs were recorded at 0, 2, 6 and 24 hr and chest scintigrams were recorded at 6 and 24 hr. Results: All venography documented thrombus sites, calves, popliteal and femor al, were detected with the radioimmunoconjugate. For the venous duplex scan-proven thrombus sites, all except two calf thrombi in two patien ts with bilateral disease and other positive sites were detected. Five patients had bilateral deep-vein thrombosis with multiple sites being visualized with the radioimmunoconjugate in the calf, popliteal and f emoral regions. One case of pulmonary embolus was also definitively de monstrated. Documented thrombus sites were detected at 2 and 6 hr post injection. Nineteen patients were on heparin. No adverse reactions to the injected dose were observed and one low titer human anti-mouse ant ibody response may have occurred. Conclusion: The results indicate tha t Tc-99m-DD-3B6/22 Fab' has potential for noninvasive detection of dee p-vein thrombosis and pulmonary embolism.