Parathyroid imaging with thallium-201 subtraction scintigraphy: a report of 33 cases.

Thallium-201 subtraction scintigraphy has been used in Wellington Hospital for preoperative localisation of parathyroid adenomas since 1984. The technique wa audited by comparing the scan reports with the outcome at operation in 33 patients, 30 of whom underwent a primary exploration. In our unselected patients we found the technique to have poor sensitivity (45.4%) with a high false positive rate (21%). There was no difference in the mean size of the glands correctly identified compared to those that were missed. Our experience has led us to believe that thallium-201 subtraction scintigraphy has not lived up to its early promise and is not a useful technique for routine preoperative localisation of parathyroid adenomas.