CEACAM5 and colorectal cancer: Finally, Gu et al [90] evaluated 29 patients with primary colorectal cancer who were injected with 0.5 mCi (18.5 MBq) of 125I-anti-CEA monoclonal antibody (125I-CL58) into the colonic submucosa at the tumor-surrounding areas (at 2, 4, 6, 8,10, and 12 o'clock locations) via colonoscopy at a time of approximately three to 14 days before RIGS.