201Tl in the scintigraphic evaluation of the "cold" thyroid areas.

201Tl-chloride, which has a metabolic behaviour similar to that of potassium and cesium, has been used in 68 patients for the evaluation of thyroid nodules previously recognized as "cold" on 131I or 99mTc scans. All patients were re-examined with gamma-camera and/or sequential scintigraphic recordings during 60 min after i.v.

201Tl for the differential diagnosis of cold thyroid nodules.

We used 201Tl-chloride for studying and differentiating thyroid areas shown to be 'cold' in previous 131I or 99mTc scanning. We investigated sixteen thyroid neoplasms that were removed surgically shortly afterwards. We found an intense intranodular accumulation of 301T1 in five scintigraphs shown to be of histologically malignant neoplasms, and an intense accumulation also in one of those shown to be histologically benign.