Noninvasive scintigraphic method to quantify unstimulated secretions from individual salivary glands

Purpose: Historically salivary gland function has been associated with maintenance of oral hygiene The difference in secretory behavior of parotid and submandibular glands has previously been shown. The purpose of this study was to establish a noninvasive technique for quantification of unstimulated (resting state) secretion of saliva based on the tracer output theory. Procedures: A total of 14 99mTc-pertechnetate salivary function studies were performed under Gamma camera. The time activity curves were subjected to a two step background subtraction protocol (area normalised background subtraction, followed by a graphical method for background correction). Individual salivary glands were modeled as Organ Curve=Input−Output. From these Uptake rates and unstimulated salivary gland fractional output rates (FOR) were calculated. Main results: Parotid as well as submandibular glands have identical Uptake rates for the tracer. A distinct pattern was noted in submandibular glands as against parotid glands. Submandibular glands showed a steady rise in total quantity of unstimulated secretion. The FOR for submandibular glands was about three times higher than parotid glands (P<0.000001). The observed distribution of FOR for parotid and submandibular glands FOR showed that parotid-FOR was normally on the lower side whereas submandibular-FOR showed a wide range of distribution which was multimodal in nature. Principal conclusion: A unique approach has been presented for quantification of unstimulated salivary secretion. The method is simple and noninvasive.