Use of a coincidence gamma camera to detect primary tumor with (18)fluoro-2-deoxy-glucose in cervical lymph node metastases from an unknown origin

This study was performed to evaluate the ability of a dual-head gamma camer a with (18)fluoro-3-deoxy-glucose coincidence detection emission tomography (FDG-CDET) to detect primary tumors in patients with cervical lymph node m etastases of head and neck squamous cell carcinoma from an unknown origin. From 60 patients with untreated head and neck squamous cell carcinoma, we s elected 4 in whom no evidence of the primary's origin was found by the conv entional methods used for the: evaluation of head and neck tumors. In addit ion to the panendoscopy, chest radiography, a computed tomography (CT) scan , and FDG-CDET were performed. Both FDG-CDET and the CT scan located cervic al lymph node metastases. In addition, FDG-CDET located the primary tumor i n 3 of the 4 patients, and the tumors were confirmed with histopathologic f indings. In contrast, the CT scan detected the primary tumor in none of the m. FDG tomography performed on a coincidence gamma camera appears to be a s uccessful new tool in detecting occult primary tumors in head and neck carc inoma, and is useful in guiding endoscopic biopsies. It has, further, the i mportant potential ability to detect distant metastases on whole body image s.