Technetium-99m trapping index as a test of thyroid function.

Thyroid examinations were performed in parallel in over 300 patients using 131I and 99mTc pertechnetate. The aim of the study was to evaluate the use of the 99mTc pertechnetate neck/thigh ratio as an index of thyroid function. Results presented indicate that the 99mTc trapping index can be reliably used as a simple and accurate index of thyroid function.