Disparate imaging of the autonomous functioning thyroid nodule with /sup 99m/Tc pertechnetate and radioiodine

Four nodules, visualized with /sup 99m/Tc pertechnetate at 20 to 60 min, were not visualized with either 123I or 131I at 2 to 4 hours. Each nodule was demonstrated to have autonomy of function in excess of surrounding normal tissue when imaged with radioiodine after TSH suppression. Rapid turnover of an iodine moiety would seem to explain this phenomenon better than the trapping-only function previously ascribed to lesions with disparate imaging using pertechnetate and iodine radionuclides