CA IX(carbonic anhydrase IX)

which is highly overexpressed in several solid tumors with limited distribution in normal tissues

is a drug target in the diagnosis and treatment of tumors.In this work

anti-carbonic anhydrase IX(CA IX) monoclonal antibody(MAb) was labeled with 99Tcm.Under the optimized conditions

the labeling yield and the radiochemical purity of 99Tcm-MAb were 85%.99Tcm-MAb was stable in NBCS and PBS.99Tcm-MAb was injected into tail vein of three nude mice bearing HT-29 tumor for planar imaging.The radioactivity was not observed in the tumor 24 h post injection(p.i.).Biodistribution at 24 h p.i.in the mice showed a little uptake of99Tcm-MAb in tumors.The planar imaging with125I-MAb at 48 h p.i.showed high concentration of radioactivity in the tumor.Because of slow metabolic cycle of Ab in the body and the short half-life of 99Tcm

99Tcm-MAb is not suitable for tumor imaging for targeting CA IX.