Intraoperative radioimmunolocalization of XXXX with a hand-held gamma probe and MAb B72.3: comparison of in vivo gamma probe counts with in vitro MAb radiolocalization.

@entity1 @entity5 @entity75 @entity189 @entity3006 @entity14 @entity694
A new intraoperative approach to @entity5 localization using radiolabelled monoclonal antibody (MAb) B72.3 involves the use of a hand-held gamma-detecting probe ( @entity3006 ) by the surgeon and, subsequently, the pathologist. We report here the use of 125I-labelled MAb B72.3 IgG and a @entity3006 to localize primary and metastatic @entity14 in 31 @entity1 . The @entity1 were administered radiolabelled MAb i.v., and all underwent surgical exploration 5 to 35 days post-injection. In vivo localization of the MAb was evaluated using a @entity3006 , with @entity5 and normal tissue counts being obtained. In each case, the subsequent @entity5 and normal tissue that were resected were analyzed in vitro for MAb localization; this was evaluated by calculating the radiolocalization index, i.e., the ratio of the injected dose per gram localized to @entity5 versus that of normal tissue. When the @entity3006 was used intraoperatively, MAb B72.3 localized @entity5 in 68% (21/31) of the @entity1 ; the arbitrary criterion of @entity5 -to-normal tissue ratios higher than or equal to 2.0:1 in vivo being taken as positive. Resected @entity5 radiolocalization indices ranged from 0.5 to 543, and 71% (22/31) of the @entity1 studied had @entity5 with radiolocalization indices higher than or equal to 3. Of 50 @entity189 biopsies, 34 that were probe-positive were antigen-positive when B72.3 was used in immunoperoxidase assays, while 4 @entity189 biopsies that were probe-negative were also antigen-negative. Twelve of 50 biopsies were probe-negative and antigen-positive, but many of these lesions only contained a few antigen-positive cells; none of the 50 was probe-positive and antigen-negative. Tumors of all histologic grades localized injected MAb and, in general, higher in vivo probe ratios and radiolocalization indices were obtained from @entity1 who underwent surgery 20 to 35 days following injection of the MAb. MAb B72.3 localized @entity5 in all sites to which @entity694 commonly metastasizes, including mesenteric and peri-aortic lymph nodes, liver, lung, and peri-rectal soft tissue. There was a strong statistical correlation (p = 0.001) between detecting MAb B72.3 localization to @entity5 using the @entity3006 intraoperatively and subsequent in vitro analysis of cpm/g for @entity5 versus normal tissues. These studies thus further validate the use of 125I-labelled MAb B72.3 IgG and of a hand-held gamma probe for the intraoperative detection of @entity75 .
