Use of 201Tl SPECT for evaluation of biologic behavior in pituitary adenomas.

UNLABELLED Although pituitary adenomas are regarded as benign tumors, some of them behave aggressively with malignant behavior of invasion and metastasis. Prediction of such biologic behavior in a tumor is important for therapeutic planning. The purpose of this study was to assess the usefulness of 201Tl chloride SPECT (201Tl SPECT) for evaluation of biologic behavior in pituitary adenomas. METHODS 201Tl SPECT was performed on 22 patients with pituitary adenomas. 201Tl uptake indices were calculated, and the results were compared between invasive pituitary adenomas and noninvasive pituitary adenomas. Correlation of the 201Tl uptake index and the MIB1 monoclonal antibody labeling index (MIB1 labeling index) of the tumors was also estimated. RESULTS In comparison with noninvasive pituitary adenomas, invasive pituitary adenomas exhibited significantly higher 201Tl uptake indices on both the early and the delayed images (P = 0.0010 and 0.0019, respectively). A significant correlation was found between the 201Tl uptake index on the delayed image and the MIB1 labeling index (P = 0.0107). CONCLUSION 201Tl SPECT can be useful for detecting biologic aggressiveness in pituitary adenomas.