[Is the "exponential fitting" in the stomach emptying curve justified?]

Gastric emptying of a solid meal labelled with 1 mCi99mTc-sulphur colloid has been studied with a gamma camera and computer in 5 healthy volunteers. The emptying process was analyzed for the three periods 0--30 min, 45--75 min, and 90-120 min after ingesting the meal. The half emptying time (T1/2) was calculated by exponential fitting for the three periods separately and an anlysis of variance of the regression slopes was performed. The nil hypothesis of no difference between the T1/2 calculated from the three periods was rejected at a level of significance of 0.01 in 13 out of 14 experiments. The authors discuss the practical implications of these findings for the use of T1/2 in the study of gastric emptying with labelled test meals.