Abstract: AIM: To study the biodistribution of ^99mTc labeled Anti-colon cancer monoclonal antibody (^99mTc-ACCmAb) in normal and nude mice and the imaging of same antibody in nude mice, which were carried with human colon cancer.METHODS: Normal mice and Nude mice that are carried the L010-16 human colon cancer received, intravenously, ^99mTc labeled monoclonal antibodies, and then the radioactivity was detected in normal mice in different time points and the imaging was checked by using the SPECT in nude mice.RESULTS: The radioactivity of ^99mTc at 6 h 5 min decreased 76.6 % in comparison with the 30 min in normal mice blood, and the radioactivity was the 23.4 % of the 30 min in the blood.The radioactivity in 6 h 5 min was 27.2 % of the 30 min in normal mice liver and decreased 76.8 %.In the normal mice injected ^99mTc-ACCmAb, the radioactivity at 6 h 5 min decreased 68.4 % compared with the 30 min in normal mice blood, the radioactivity was the 31.6 %of the 30min in the blood, the radioactivity at 24 h are 6.1 %and it dropped 93.9 % compare with the 6 h 5 min.In nude mice, the radioactivity of ^99mTc-ACCmAb at 24 h is 2.1 % of the first half-life.It decreased 97.9 % compared with the 6 h 5 min.Although the ratio of blood and tumor was the highest, the imaging results were still better than other time points.CONCLUSION: ^99m Tc-ACCmAb may concentrate in nude mice, which are carried with human colon carcinoma.It may become the diagnostic reagent for radio-immunoguided and ensure to remove the tumor during operations.

Key words: ^99m Tc-ACCmAb, colon cancer, distribution, SPECT radio-imaging