RESUMEN
The purpose of this study was to evaluate the usefulness of thallium-201-chloride (Tl-201) scintigraphy for the examination of patients with tumors of the head and neck, and to estimate the correlation of the expression of Na<sup>+</sup>/K<sup>+</sup>-ATPase with Tl-201 scintigraphy. Tl-201 scintigraphy was performed in 61 patients with squamous cell carcinoma and 10 patients with benign tumors of the salivary gland. The tumor retention index was obtained from the early and delayed dynamic Tl-201 scintigraphies. The expression of Na<sup>+</sup>/K<sup>+</sup>-ATPase on the cell membrane was evaluated immunohistochemically. Evaluation of correlations between the histopathological tissue differentiation of tumors, the tumor retention index of Tl-201 scintigraphy and the expression of Na<sup>+</sup>/K<sup>+</sup>-ATPase was performed. The tumor retention index of Tl-201 scintigraphy correlated well with the histopathological tissue differentiation of tumors and also showed a good correlation with the expression of Na<sup>+</sup>/K<sup>+</sup>-ATPase. In addition, the expression of Na<sup>+</sup>/K<sup>+</sup>-ATPase demonstrated a close correlation with the histopathological tissue differentiation of malignant tumors. The tumor retention index could be used for the differentiation of malignant tumors from benign tumors and the expression of Na<sup>+</sup>/K<sup>+</sup>-ATPase was estimated as one of the most important factors for Tl-201 accumulation in malignant tumors.