Simultaneous Quantitative Measurement of ¹³¹I‐Iodine and ⁹⁹mTc‐Pertechnetate Uptake by Human Salivary Glands Using Scintiscanning with Validation by Direct Estimation in Biopsy Samples

Abstract. 131 I‐iodide and 99 Tc‐pertechnetate concentration in human salivary glands has been measured simultaneously in vivo by quantitative scintiscanning in 7 thyrotoxic subjects. The mid scan times were 5, 12 and 20 min. and the gland to plasma ratio (G/P) of 131 I rose to 4.03±0.82 (s.e.) in the parotid and 10.7 ±3.1 (s.e.) in the submandibular glands. Corresponding values for G/P 99m TcO 4 ‐were 2.70 ±0.34 in the parotid and 5.3 ± 1.2 in the submandibular glands. Values obtained at parotidectomy 1 h after intravenous administration of a mixture containing 125 I ‐ and 99m TcO 4 ‐ to 6 patients were 4.13 ± 0.85 for G/P 125 I‐ and 2.50 ± 0.62 for G/P 99m TcO 4 ‐. G/P 131 I‐ (or G/P 125 I‐) and G/P 99m TeO 4 ‐, derived by both methods, were significantly correlated in parotid and submandibular glands. There was a significant correlation between G/P 131 I‐/G/P 99m TcO 4 ‐ in the parotid glands and G/P 131 I‐/G/P 99m TcO 4 ‐ in the submandibular glands. ‐It is concluded that 1. salivary gland values of 131 I ‐ and 99m TcO 4 , ‐ as measured by scintiscanning are very close to values obtained by direct counting of excised human salivary gland tissue and 2. that the secretion processes in both glands are physiologically related.