Carbon-11-methionine positron emission tomography imaging of chordoma.
OBJECTIVE
Chordoma is a rare malignant bone tumor that arises from notochord remnants. This is the first trial to investigate the utility of (11)C-methionine (MET) positron emission tomography (PET) in the imaging of chordoma before and after carbon-ion radiotherapy (CIRT).


METHODS
Fifteen patients with chordoma were investigated with MET-PET before and after CIRT and the findings analyzed visually and quantitatively. Tumor MET uptake was evaluated by tumor-to-nontumor ratio (T/N ratio).


RESULTS
In 12 (80%) patients chordoma was clearly visible in the baseline MET-PET study with a mean T/N ratio of 3.3+/-1.7. The MET uptake decreased significantly to 2.3+/-1.4 after CIRT ( P<0.05). A significant reduction in tumor MET uptake of 24% was observed after CIRT. Fourteen (93%) patients showed no local recurrence after CIRT with a median follow-up time of 20 months.


CONCLUSIONS
This study has demonstrated that MET-PET is feasible for imaging of chordoma. MET-PET could provide important tumor metabolic information for the therapeutic monitoring of chordoma after CIRT.
Department of Medical Imaging, National Institute of Radiological Sciences, Chiba, Japan.
Hong
H
Zhang
Kyosan
K
Yoshikawa
Katsumi
K
Tamura
Kenji
K
Sagou
Mei
M
Tian
Tetsuya
T
Suhara
Susumu
S
Kandatsu
Kazutoshi
K
Suzuki
Shuji
S
Tanada
Hirohiko
H
Tsujii
D000368:Aged; D000369:Aged, 80 and over; D002250:Carbon Radioisotopes / Q000627:therapeutic use; D002817:Chordoma / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D019583:Dose Fractionation, Radiation; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D012447:Sacrum / Q000000981:diagnostic imaging* / Q000528:radiation effects; D013125:Spinal Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy
D002250:Carbon Radioisotopes