FAP and colorectal carcinoma: In the first study, Welt et al. used the chloramine T method to label the F19 mAb with Iodine-131 (131I: β−—emitter: t1/2 = 8.0 d; E β−max = 0.97 MeV) to prepare [131I]I-F19 mAb in order to determine if the radiolabeled antibody could detect FAP expression in colorectal carcinoma tumors.