口腔扁平上皮癌の画像診断における塩化タリウムSPECTの臨床的検討

抄録

Recently the usefulness of Thallium 201 chloride (201T1) as a tumor imaging agent for various tumors has been reported However, the application of 201T1 SPECT to oral squamous cell carcinomas has not been established The purpose of this study is to investigate the usefulness of 201T1 SPECT in the assessment of malignancy or in the differential diagnosis of oral squamous cell carcinomas from inflammatory diseases. Thirty-two patients with 33 primary oral squamous cell carcinomas and 4 patients with inflammatory disease were studied SPECT images were acquired 15 minutes (early image) and 3 hours (delayed image) after the intravenous injection with 74MBq 201Tl, and then early uptake ratio (ER), delayed uptake ratio (DR), and retention index (RI) were measured The relations between these parameters and the size, the site, the degree of differentiation and the mode of invasion of the primary tumor were analyzed statistically. 201T1 SPECT correctly identified 32 of the 33 tumors, with 32 patients having oral squamous cell carcinoma, making the positive rate 97% Significant negative correlation was observed between RI and major or minor axis of tumors, therefore, this study revealed that RI was influenced by the size of a tumor In comparison with the average value of RI according to histopathological diagnosis, there was statistically significant difference (p=0011) between carcinomas (0 80±0 16, n=30) and inflammatory diseases (0 58±0 04, n=4), thus, it was supposed that differential diagnosis between them could be possible About the tumors with the range of minor-axis 20mm-40mm for little influence of tumor size to the RI, the tendency to decrease for the RI of well-differentiated group or low-invasive group was seen. For oral squamous cell carcinomas, 201T1 SPECT had a high positive rate The application was suggested for use in the differential diagnosis between inflammatory disease and carcinomas, where clinical usefulness could be expected.