PET and autoradiography using 18F-tetrazine agents. (a) PET/CT fusion of LS174T tumor xenograft labeled using either trans-cyclooctene (TCO) monoclonal antibodies (mAb TCO) or control unlabeled antibodies (mAb) followed by 18F-PMT10 (polymer-modified tetrazine). Arrows indicate location of the tumor xenograft. The bladder was omitted for clarity. (b) Imaging using autoradiography (left side) and fluorescence slices after targeting with fluorescence TCO monoclonal antibody and 18F-PMT10. (c) PET/CT fusion of mouse bearing A431 and LS174T tumors after targeting with anti-A33 TCO monoclonal antibodies followed by 18F-PMT10. Arrows indicate location of tumors and the liver was omitted for clarity. (d) Autoradiography of representative 1 mm LS174T and A431 tumor slices after multistep targeting (reprinted with permission from [80]; Copyright 2012 National Academy of Sciences of the United States of America).
