[Questionable hyperparathyroidism: diagnostic value of thallium-technetium subtraction scintigraphy]

The diagnostic exclusion of hyperparathyroidism belongs to the standard repertoire of a practicing urologist involved in stone prophylaxis. Primary indicators of hyperparathyroidism are increases in serum calcium and in parathyroid hormone. Additional diagnostic methods are needed, since the methods most often used so far are inadequate, especially insofar as adenomas and ectopic tumors or recurrences can remain unrecognized. Exploratory surgical intervention means a difficult and traumatizing operation. Therefore, a sensitive technique for localization of adenomas is an urgent necessity. Thallium-pertechnetate subtraction scintigraphy was first introduced for localization of an adenoma of the parathyroid by Ferlin's group. This technique yielded better results than any previously known methods, with a success rate of 92%. The object of the present paper is not only to present a method that is not yet sufficiently well accepted among urologists, but also to offer a critical evaluation of the examination results known so far. The method cannot yet make exploratory surgery unnecessary, even when clinical and biochemical examinations give rise to a strong suspicion. However, since ectopic adenomas and possible relapse can be recognized with 90-100% accuracy, which is important in deciding on the surgical strategy, the method should be included in the preoperative diagnostic armamentarium.