A noninvasive scintigraphic assessment of the colonic transit of nondigestible solids in man.

A noninvasive, scintigraphic technique for quantifying large intestinal transit time that provides low radiation doses was developed. The scintigraphic large intestinal transit (SLIT) method uses a total of 100 microCi of 111In encapsulated in ten 2-cm nondigestible capsules, which are ingested after a 6-hr fast. Two hundred fifty microcuries of 99mTc-sulfur colloid were given to outline the gastrointestinal tract. Images were acquired at 4-hr intervals until all capsules were excreted. Normal volunteers (n = 10) consumed a standardized diet 2 days prior and during imaging. Segmental transit times were measured in the following: ascending, transverse, descending, recto-sigmoid colons; hepatic and splenic flexures. The radiation absorbed dose to the large intestine for the SLIT technique is less than half of that associated with other radiographic methods of colonic transit time measurement.