title: Imaging of gynecologic tumors: comparison of (11)C-choline PET with (18)F-FDG PET.
abstract: This study was designed to compare the value of PET using (11)C-choline with that of PET using (18)F-FDG for the diagnosis of gynecologic tumors.
  
  
  METHODS
  We examined 21 patients, including 18 patients with untreated primary tumors and 3 patients with suspected recurrence of ovarian cancer. (11)C-choline PET and (18)F-FDG PET were performed within 2 wk of each other on each patient. The patients fasted for at least 5 h before the PET examinations, and PET was performed 5 min ((11)C-choline) and 60 min ((18)F-FDG) after injection of each tracer. PET images were corrected for the transmission data, and the reconstructed images were visually analyzed. Then, the standardized uptake value (SUV) was calculated for quantitative assessment of tumor uptake. PET results were compared with surgical histology or >6 mo of clinical observations.
  
  
  RESULTS
  Of 18 untreated patients, (11)C-choline PET correctly detected primary tumors in 16 patients, whereas (18)F-FDG PET detected them in 14 patients. In 1 patient with small uterine cervical cancer and 1 diabetic patient with uterine corpus cancer, only (11)C-choline PET was true-positive. Both tracers were false-negative for atypical hyperplasia of the endometrium in 1 patient and were false-positive for pelvic inflammatory disease in 1 patient. For the diagnosis of recurrent ovarian cancer (n = 3), (11)C-choline PET and (18)F-FDG PET were true-positive in 1 patient, whereas neither tracer could detect cystic recurrent tumor and microscopic peritoneal disease in the other 2 patients. In the 15 patients with true-positive results for both tracers, tumor SUVs were significantly higher for (18)F-FDG than for (11)C-choline (9.14 +/- 3.78 vs. 4.61 +/- 1.61, P < 0.0001). In 2 patients with uterine cervical cancer, parailiac lymph node metastases were clearly visible on (18)F-FDG PET but were obscured by physiologic bowel uptake on (11)C-choline PET.
  
  
  CONCLUSIONS
  The use of (11)C-choline PET is feasible for imaging of gynecologic tumors. Unlike (18)F-FDG PET, interpretation of the primary tumor on (11)C-choline PET is not hampered by urinary radioactivity; however, variable background activity in the intestine may interfere with the interpretation.
authors.affiliation: Positron Medical Center, Hamamatsu Medical Center, Hamakita, Japan. tatsuo@pmc.hmedc.or.jp
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Torizuka
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Kanno
authors.forename: Masami
authors.initials: M
authors.lastname: Futatsubashi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Okada
authors.forename: Etsuji
authors.initials: E
authors.lastname: Yoshikawa
authors.forename: Fumitoshi
authors.initials: F
authors.lastname: Nakamura
authors.forename: Munetaka
authors.initials: M
authors.lastname: Takekuma
authors.forename: Makoto
authors.initials: M
authors.lastname: Maeda
authors.forename: Yasuomi
authors.initials: Y
authors.lastname: Ouchi
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D000328:Adult; D000368:Aged; D002250:Carbon Radioisotopes; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D002296:Carcinosarcoma / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D002794:Choline; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18; D005833:Genital Neoplasms, Female / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D009367:Neoplasm Staging / Q000379:methods; D010051:Ovarian Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012509:Sarcoma; D018227:Sarcoma, Clear Cell / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed / Q000379:methods*; D014594:Uterine Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D014915:Whole-Body Counting
chemical_list: D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D002794:Choline