経時的唾液腺シンチグラフィーによる唾液腺機能の定量的評価

抄録

Salivary gland function was evaluated quantitatively using sequential salivary gland scintigraphy. ^99mTc-pertechnetate at a dose of 3m Ci was i.v. administered. The analysis was performed by means of gamma camera attached with high resolution parallelhole collimator or bilateral collimator and computer system. As a stimulation test, 200mg ascorbic acid granules were i.v. administered after 35 minutes. Bilateral parotid and submandibular glands were selected as region of interest (ROI) and the average value was calculated for data analysis.
Subjects enrolled in this study included 20 cases of normals, 21 cases of suspected Sjögren's syndrome, 5 cases of established Sjögren's syndrome, 20 cases of xerostomia and 10 cases of radiation xerostomia.
The analysis was made by determining parameters as follows: 1) RI uptake by parotid gland at 10, 20, 30 minutes after injection, 2) RI uptake by submandibular gland at, 10, 20, 30 minutes after injection, 3) maximum uptake time, 4) uptake ratio of left to right parotid glands, 5) secretion rate after stimulation, 6) reaction time after stimulation, 7) RI uptake by parotid gland at 40, 50, 60 minutes after injection, and 8) RI uptake by submandibular gland at 40, 50, 60 minutes after injection.
Concerning RI uptake rate by parotid and submandibular glands, these values in patients with suspected Sjögren's syndrome, xerostomia and radiation xerostomia increased with time lapse similar to those in normal cases. In established Sjögren's syndrome, however, higher uptake rates were obtained at, 10, 20, and 30 minutes after injection with both parotid and submandibular glands. The maximum uptake time by parotid and submandibular glands in normal subjects were 31.4±3.7 and18.4±10.4 minutes respectively. A significant difference as for the maximum uptake time was noted only in patients with suspected Sjögren's syndrome. The uptake ratio of left to right parotid glands showed no difference in patients with suspected and established Sjögren's syndrome and xerostomia. Some higher left to right uptake ratios were observed in several patients with radiation xerostomia. Although decreased secretion rate and/or delayed reaction time after stimulation were noted in established Skigren's syndrome and radiation xerostomia cases, no difference was observed in suspected Sjögren's syndrome and xerostomia cases as compared to normal subjects.
RI uptake by parotid and submandibular glands at 10 and 40 minutes after injection, secretion rate and reaction time after stimulation were useful for evaluating salivary gland function.
A quantitative analysis using sequential salivary scintigraphy is considered to be a valuable technique for evaluating various salivary gland diseases.