The importance of background correction during calculation of the major salivary gland function in salivary gland scintigraphy

Abstract

Objective: The aim of this study was to compare the parotid (P) and submandibular (SM) glands uptake and excretion ratios of 99mTc-pertechnetate, which were calculated by using the backgrounds drawn on five different areas. Methods: Ninety-eight P and 98 SM glands of totally 48 patients were included in the study. 99mTc-pertechnetate salivary gland scintigraphy was performed in all patients. Oral stimulation with lemon juice was made at 15th minute of the imaging. The 99mTc-pertechnetate uptake and excretion ratios of the P and SM glands were calculated separately without using any background, and by using the backgrounds drawn on wide frontal, narrow frontal, temporal, cervical and shoulder regions. These values were statistically compared with each other in pairwise manner. Results: The radioactivity uptake and excretion ratios of the P and SM glands calculated without using any background correction were statistically different from that calculated by using any background correction. In addition, the radioactivity uptake and excretion ratios of the P and SM glands calculated by using the backgrounds drawn on five different areas were mostly found statistically different from each other (p<0.05). Conclusion: Background correction is important during the calculation of the uptake and excretion ratios of P and SM glands. This study demonstrates that calculated uptake and excretion ratios of P and SM glands may differ according to the used background area