Radiology, Vol 179, 509-512, Copyright © 1991 by Radiological Society of North America
Improved tumor imaging with radiolabeled monoclonal antibodies by plasma clearance of unbound antibody with anti-antibody column
JL Lear, RK Kasliwal, AJ Feyerabend, JP Pratt, PA Bunn, DG Dienhart, R Gonzalez, TK Johnson, DC Bloedow and SW Maddock
Division of Nuclear Medicine, University of Colorado Health Sciences Center, Denver 80262.
Imaging of tumors by using radiolabeled monoclonal antibodies (MoAs) is
hindered by the presence of background activity. To reduce this problem,
the authors investigated the process of removing labeled MoAs from plasma
at selected times by means of extracorporeal immunoadsorption. In seven
patients with either lung or breast carcinoma, an indium-111-labeled murine
antibody was intravenously administered. Six to 24 hours later,
immunoadsorption was performed by passing the patients' plasma through a
goat anti-mouse antibody column connected to a plasma separator. Whole-body
computer images were obtained before and after the treatment. Blood pool
activity in the images was reduced by an average of 59%, while tumor
activity dropped by only 10%. Tumor-to-blood activity ratios therefore more
than doubled, improving by an average of 121% between the pre- and
posttreatment image sets. Eight of 12 areas of known disease and three
areas of unknown but later documented disease were detected after the
immunoadsorption process, while the three areas of unknown disease and
three of the areas of known disease were not detected in the preclearance
images. Thus, the feasibility of using extracorporeal immunoadsorption to
improve MoA imaging of tumors was demonstrated.
