Head and Neck Tumors and Neck Node Metastasis: Comparison of Ga-67 Scan and CT Findings

ABSTRACT

PURPOSE: To assess relative diagnostic value of Ga-67 planar, Ga-67 SPECT, and CT images for detection of head and neck tumors and cervical lymph node metastasis. MATERIALS AND METHODS: Thirty eight patients of pathologically proven head and neck tumors including squamous cell carcinomas(n=32), malignant lymphomas(n=3), undifferentiated carcinomas(n=2), adenocarcinomas(n=l) were enrolled in this study. Ga-67 planar and SPECT images were obtained with intravenous injection of 5mCi of Ga-67 citrate. On the basis of 30 and 20 mm in the greatest diameter of cervical lymph nodes, we compared lesion detectability of Ga-67 planar, SPECT, and CT. RESULTS: Thirty eight cases of head and neck tumors were detected in 29 cases(76.3%) with Ga-67 planar image, 37 cases(97.3%) with Ga-67 SPECT, and 32 cases(84.2%) with CT. 25 of 32 squamous cell carcinomas were positive with Ga-67 planar image and all of 32 cases with Ga-67 SPECT. Both of two undifferentiated carcinomas were positive with Ga-67 planar and SPECT images. Two of three malignant lymphomas were positive with Ga-67 planar image and all of three with Ga-67 SPECT. Eight of nine tumors were negative with Ga-67 planar image and those were less than 30ram. One case of adenocarcinoma was negative with Ga-67 planar and SPECT images. Seven of nine lymph nodes greater than 30mm were positive with Ga-67 planar image and all of nine with Ga-67 SPECT. On the basis of 20mm in greatest diameter, 16 of 21 lymph nodes greater than 20 mm were positive with Ga-67 planar and SPECT images. CONCLUSION: CT providing better resolution than Ga-67 scan permitted analysis of size and location of metastatic cervical nodes, however primary tumors of oral cavity, vocal cord, and nasopharynx were often not detected on CT when metallic and motion artifacts were present, where Ga-67 SPECT was useful. Ga-67 SPECT enabled better anatomical localization than Ga-67 planar image and was useful in detection of lymph nodes greater than 30 mm.