Influence of the particle size of activated charcoal on labeling efficiency with 67Ga-citrate for colonic transit study

Indium-111 and 99mTc have been proposed for colonic transit study, but 111In is expensive and the half-life of 99mTc is too short for the study. Gallium-67 citrate is inexpensive and has a suitable half-life. In our previous study, we successfully labeled 67Ga-citrate activated charcoal, and the labeling efficiency exceeded 91% after a 96 hour incubation period. In this work, we evaluated the influence of the size of activated charcoal particles on the labeling efficiency with 67Ga-citrate. The data showed that the influence of particle size on the labeling efficiency of activated charcoal with 67Ga was insignificant. Both sizes of activated charcoal particles can be used for labeling with 67Ga in colonic transit study.