Evaluation of 99mTc-sulfonamide and sulfocoumarin derivatives for imaging carbonic anhydrase IX expression

99mTc(I) and Re (I) complexes with sulfonamide or sulfocoumarin targeting units were synthesized as potential hypoxia tumor imaging agents. The Re sulfocoumarin derivatives were inactive against hCA-I, -II and -IV, but exhibited moderate affinity for hCA-IX. However, uptake in HT-29 tumors was highest for the 99mTc sulfoamide derivative.193