Imaging of gynecologic tumors: comparison of (11)C-choline PET with (18)F-FDG PET.
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.
Torizuka
Tatsuo
T
Positron Medical Center, Hamamatsu Medical Center, Hamakita, Japan. tatsuo@pmc.hmedc.or.jp
Kanno
Toshihiko
T
Futatsubashi
Masami
M
Okada
Hiroyuki
H
Yoshikawa
Etsuji
E
Nakamura
Fumitoshi
F
Takekuma
Munetaka
M
Maeda
Makoto
M
Ouchi
Yasuomi
Y
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
D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D002794:Choline