Definition

A radioconjugate composed of an isatin sulfonamide analog labeled with the positron-emitting isotope fluorine F 18, with potential imaging activity for activated caspase-3, which is a marker for apoptosis, using positron emission tomography/computed tomography (PET/CT). Upon administration, fluorine F 18 WC-4-116 is preferentially taken up by and accumulates in cells with high caspase-3 activity. Upon PET/CT imaging, caspase-3 activation may be detected, and apoptotic activity, including chemotherapy-induced tumor apoptosis, may be assessed. Caspase-3, a cysteine protease, plays an important role in apoptosis.