Comparison of (11)C-choline and (18)F-FDG PET in primary diagnosis and staging of patients with thoracic cancer.

UNLABELLED PET with (18)F-FDG is used for detection and staging of thoracic cancer; however, more specific PET radiopharmaceuticals would be welcome. (11)C-labeled choline (CHOL) is a new radiopharmaceutical potentially useful for tumor imaging, since it is incorporated into cell membranes as phosphatidylcholine. The aim of this study was to investigate whether (11)C-CHOL PET has advantages over (18)F-FDG PET in patients with thoracic cancer. METHODS We evaluated 17 patients with thoracic cancer both with (11)C-CHOL PET and (18)F-FDG PET. After transmission scanning, (11)C-CHOL was injected intravenously, and whole-body scanning was started after 5 min. Immediately thereafter, (18)F-FDG was injected intravenously, followed after 90 min by interleaved attenuation-corrected whole-body scanning. Scans were performed from crown to femur. Visual and quantitative (standardized uptake value) analyses of (11)C-CHOL PET and (18)F-FDG PET were performed and compared with results of traditional staging and follow-up. RESULTS The most prominent features of normal (11)C-CHOL distribution were high uptake in liver, renal cortex, and salivary glands. Except for some uptake in choroid plexus and pituitary gland, brain uptake was negligible. All primary thoracic tumors were detected with (11)C-CHOL PET and (18)F-FDG PET. Both (11)C-CHOL PET and (18)F-FDG PET correctly identified all 16 patients with lymph node involvement. However, in a lesion-to-lesion analysis, (11)C-CHOL PET detected only 29 of 43 metastatic lymph nodes, whereas (18)F-FDG PET detected 41 of 43. (11)C-CHOL PET detected fewer intrapulmonary and pleural metastases than (18)F-FDG PET (27/47 vs. 46/47). More brain metastases were detected with (11)C-CHOL PET (23/23) than with (18)F-FDG PET (3/23). For primary tumors, the median (range) standard uptake values of (11)C-CHOL and (18)F-FDG were 1.68 (0.98-3.22) and 4.22 (1.40-8.26), respectively (P = 0.001). CONCLUSION (11)C-CHOL PET can be used to visualize thoracic cancers. Although detection of lymph node metastases with (11)C-CHOL PET was inferior compared with (18)F-FDG PET, the detection of brain metastases was superior.