Accumulations in the salivary gland due to Tc-99m pertechnetate imaging improved after isotope therapy for Graves' disease.

Figure 1. Salivary gland scintigraphy performed before (March 2005) and after (August 2005) iodine-131 internal radiation therapy (I-131 IRT). Anterior images obtained at 10 and 20 minutes after intravenous injection of Tc-99m, and at 5 minutes after washout by Vitamin C are shown. Original scintigraphy was performed as a dynamic study with 1 min/frame. Significantly higher accumulation was observed in both parotid glands after I-131 IRT. Tracer washout into the oral cavity was also higher after the I-131 IRT. For comparison of function before and after I-131 IRT, the right and left parotid counts divided by background count are shown in the table, in which the background was defined as the average submandibular count just after washout. The improved function after I-131 IRT was also supported by the quantification. □ SHORT COMMUNICATION □