99mTc-pertechnetate in the detection of thyroid carcinoma in a ten year period.

During a 10-year period, 63 patients with thyroid malignancies were imaged with 99mTc-pertechnetate (99mTc) and 9 of them also underwent imaging with 131I. To evaluate 99mTc in the detection of thyroid carcinoma, the scans were blindly analyzed and compared with the reports of surgeons and pathologists. The carcinomas were located in hypoactive nodules in 60 cases, there were cold nodules in the three remaining thyroids, but accurate localization of the carcinomas was not possible, however, it seemed that only one of these could have been situated either in a hot or a cold nodule. The 99mTc and 131I images were almost the same. The most common carcinomas were papillary (46%) and follicular (38%) forms. More than one hypoactive nodule was detected in 48% of patients, two or more carcinoma nodules were noted in 17%, and multinodular goitre in 29% of patients. Our study confirms the usefulness of 99mTc in carcinoma detection, we suggest that reimaging of all the functioning nodules on the 99mTc scan with radioiodine, as recommended by many authors, is neither necessary nor justifiable.