We estimated the serum levels of SCC-Ag, CEA and TPA in 69 patients with head or neck neoplasia and 31 healthy patients using a radioimmunometric method (double antibody). SCC-Ag concentrations were significantly increased in 43.4% cancer patients with respect to the cut-off point value (1.7 ng/ml) of the control group, and the specificity was 96.7%. The data varied according to the evolutive phase of disease. Since the combined evaluation of SCC-Ag, TPA and CEA serum levels increased the sensitivity, that was 71.0%, we thought it opportune to use all these markers in the tumoral pathology taken into consideration.

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. administration of thallium. In some cases, simultaneous imaging and integral digital plot with 131I or 99mTc and 201Tl were performed. In all 12 malignant nodules, 201 Tl has showed a high uptake, while it did not concentrate in 47 benign nodules (cystic or macrofollicular adenomas); thallium uptake was nevertheless found in 10 solid neoformations in which histological pictures were negative for malignancy or atypical lesions. The computerized study of the 201Tl intranodular concentration, with the analysis of its dynamic function curves, seems to offer further possibility in differentiating and in a more objective evaluation of the "cold" areas on the thyroid scan.

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Radiothallium (201TI) has been proposed as a tracer in nuclear medicine for the diagnosis of cold thyroid nodules. Its potassium-mimetic characteristics, like those of 131Cs, can provide information on its turnover in the thyroid nodules; this serves as a basis for the distinction between benign and malignant thyroid tumours. The author presents a study on the diagnostic efficacy of 201TI as a tracer for thyroid nodules with the aim of evaluating the dynamic uptake and the biodistribution of 201TI after intravenous injection of 555–740 kBq/kg. A quantitative analysis was made by continuous scanning of 201TI distribution during the first 20–30 min following thallium injection, with further surveys from 40 to 60 min or more when fixation in a nodule was demonstrated. The ratio between 201TI uptakes in the nodule and in healthy tissue (density index) was calculated and a multiparametric analysis of the corresponding activity/ time curves was performed. This study included 176 patients. Concordance between clinico-histological diagnosis and radio-isotopic findings was demonstrated in 102 out of 106 colloidocystic goitres, in 42 out of 48 benign nodules including thyroiditis, and in 21 out of 22 malignant tumours; a significant statistical difference in the density index between solid and cystic nodules, but no difference between benign and malignant nodules; and a different201 Tl dynamic behaviour in nodules of different nature, with a clear statistical difference in the thallium release between malignant nodular and healthy tissue (nodular disappearance index). This method can improve the diagnosis value of scintigraphy for thyroid nodules enhancing the sensitivty of the radioisotopic applications in comparison with other non-invasive techniques.

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