Technetium 99m-methoxyisobutylisonitrile in early diagnosis of thyroid cancer

The study was aimed at evaluation of applicability of 99mTc-labeled MIBI accumulation for early diagnosis of thyroid cancer. The investigated group included 16 patients with cold nodules of the thyroid in whom the presence of thyroid cancer or thyroid adenoma was diagnosed by means of a thin-needle biopsy. All the patients studied were subjected to surgical treatment. Prior to the operation, each patient was subjected to scintigraphic examination of the thyroid 10 minutes after intravenous administration of 185 MBq (5 mCi) 99mTc-MIBI. Scintigraphy was performed by using a ZLC Digitrac gamma camera of Siemens equipped with a Micro Delta computer. The accumulation of the tracer within the cold nodules was demonstrated in 11 patients with thyroid cancer (7 with follicular cancer, 2 with papillary cancer, 1 with anaplastic cancer and 1 with metastases to the thyroid) and in 2 patients with thyroid adenoma. This represents diagnostic accuracy of 0.85 in cases of thyroid cancer and 0.65 in cases of thyroid adenoma. Two conclusions can be formulated on the basis of the results obtained: first conclusion is that both thyroid cancer and thyroid adenoma do exhibit the ability to accumulate 99mTc-MIBI; the second conclusion is that 99mTc-labeled MIBI as used for scintigraphy of cold nodules of the thyroid is an useful marker of thyroid cancer in its early phase.