[Efficacy of pancreatic scan--comparison among conventional scan, SPECT and X-CT]

We studied the efficacy of pancreas scintigraphy using 75Se-selenomethionine by conventional method and SPECT in 26 patients diagnosed as pancreatic tumor or pancreatitis. X-CT was also performed in all patients and compared its efficacy with that of scintigraphy. In order to evaluate the image quality, 4 doctors analysed the images independently without clinical information and score them according to the possible abnormality. The average score of each film was adopted as an index for sensitivity, and the standard deviation was evaluated as objectiveness of the images. As for the detection of pancreatic tumor, both the sensitivity and the objectiveness of X-CT were superior to those of scintigraphies. However, evaluation by scintigraphy combined with X-CT increased the diagnostic sensitivity of pancreatitis than that of X-CT alone in some cases. These results suggest that the scintigraphy has no indication to suspected pancreatic tumor, but it still has some value in limited cases of pancreatitis. Almost no advantage was noted in SPECT combined with conventional image. Main reason was the artifact of SPECT preventing the accurate interpretation. Only benefits of SPECT were to decrease the false positive rate and to increase the objectiveness of 75Se-selenomethionine scan. When the scan is discussed as the examination, careful considerations should be done on the point of limited advantage on diagnostic efficacy and marked disadvantage of radiation to patients and environment.