Comparative PET imaging of experimental tumors with bromine-76-labeled antibodies, fluorine-18-fluorodeoxyglucose and carbon-11-methionine.
The potential of a 76Br-labeled anti-carcinoembryonic antigen monoclonal antibody (MAb), 38S1, as tumor-imaging agent for PET was investigated in a comparative experimental study with [18F]fluorodeoxyglucose ([18F]FDG) and L-[methyl-11C]methionine ([11C]Met).


METHODS
The three radiotracers were administered to nude rats carrying subcutaneous xenografts or liver metastases from a human colonic carcinoma. Tracer biodistribution was evaluated by PET imaging and radioactivity measurement of dissected tissues and also by whole-body autoradiography for subcutaneous xenografts.


RESULTS
For PET imaging of subcutaneous tumors, 76Br-38S1 proved superior to the other radiotracers. Tumor-to-tissue ratios were, except for the tumor-to-blood ratio, generally higher for 76Br-labeled MAb than for [18F]FDG and [11C]Met. Liver metastases were imaged with PET using both 76Br-38S1 and [18F]FDG, and the metastases-to-liver ratios of dissected samples were not significantly different for the two radiotracers.


CONCLUSIONS
The tumor-imaging capacity of 76Br-labeled MAb 38S1 was superior to [18F]FDG and [11C]Met in the subcutaneous tumor model, whereas 76Br-38S1 and [18F]FDG were equally successful for the identification of liver metastases.
Lövqvist
A
A
Department of Diagnostic Radiology, Uppsala University, Sweden.
Sundin
A
A
Roberto
A
A
Ahlström
H
H
Carlsson
J
J
Lundqvist
H
H
D000818:Animals; D000911:Antibodies, Monoclonal; D001345:Autoradiography; D001967:Bromine Radioisotopes / Q000493:pharmacokinetics; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics; D002272:Carcinoembryonic Antigen / Q000276:immunology; D003847:Deoxyglucose / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics; D019788:Fluorodeoxyglucose F18; D008715:Methionine / Q000493:pharmacokinetics; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000000981:diagnostic imaging*; D016719:Radioimmunodetection; D051381:Rats; D011923:Rats, Nude; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed
D000911:Antibodies, Monoclonal; D001967:Bromine Radioisotopes; D002250:Carbon Radioisotopes; D002272:Carcinoembryonic Antigen; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; C086242:carbon-11 methionine; D003847:Deoxyglucose; D008715:Methionine