Thallium-201 SPECT and technetium-99m-phytate subtraction liver imaging in the evaluation of pancreatic cancers.

Unlabelled: We preliminarily evaluated the usefulness of 201Tl SPECT in the investigation of pancreatic cancers.

Methods: The subjects included 32 patients with malignant tumors, 16 with benign disorders and 10 controls. SPECT was performed 10 min after the injection of 148-222 MBq of 201Tl; subjects had fasted to minimize intestinal activity. In addition, subtracted SPECT using 99mTc-phytate to separate the boundary of abnormal uptake from liver activity was carried out in 14 patients.

Results: Thallium-201 did not accumulate in the pancreatic bed of the controls. In contrast, 29 of the 32 patients with malignant tumors showed positive phytate uptake with a sensitivity of 90.6% in the detection of malignancy. Of the 16 benign disorders, only four patients showed abnormal uptake; however, the mean value of the lesion-to-hepatic ratio (0.43 +/- 0.06; range, 0.35-0.51), as an index of the degree of uptake, was lower than that in positive malignant tumors (0.72 +/- 0.16; range, 0.53-1.28). Thallium-201 activity per milligram of resected cancer tissue in two patients was 2-3 times greater than in normal tissue. Follow-up 201Tl SPECT in the five treated patients demonstrated similar alterations between 201Tl uptake and tumor markers.

Conclusion: Our results suggest that 201Tl SPECT may have clinical potential in the investigation of pancreatic cancers.