18F-FET PET compared with 18F-FDG PET and CT in patients with head and neck cancer.
Recent studies suggest a somewhat selective uptake of O-(2-[18F]fluoroethyl)-L-tyrosine (FET) in cerebral gliomas and in squamous cell carcinoma (SCC) and a good distinction between tumor and inflammation. The aim of this study was to investigate the diagnostic potential of 18F-FET PET in patients with SCC of the head and neck region by comparing that tracer with 18F-FDG PET and CT.


METHODS
Twenty-one patients with suspected head and neck tumors underwent 18F-FET PET, 18F-FDG PET, and CT within 1 wk before operation. After coregistration, the images were evaluated by 3 independent observers and an ROC analysis was performed, with the histopathologic result used as a reference. Furthermore, the maximum standardized uptake values (SUVs) in the lesions were determined.


RESULTS
In 18 of 21 patients, histologic examination revealed SCC, and in 2 of these patients, a second SCC tumor was found at a different anatomic site. In 3 of 21 patients, inflammatory tissue and no tumor were identified. Eighteen of 20 SCC tumors were positive for both 18F-FDG uptake and 18F-FET uptake, one 0.3-cm SCC tumor was detected neither with 18F-FDG PET nor with 18F-FET PET, and one 0.7-cm SCC tumor in a 4.3-cm ulcer was overestimated as a 4-cm tumor on 18F-FDG PET and missed on 18F-FET PET. Inflammatory tissue was positive for 18F-FDG uptake (SUV, 3.7-4.7) but negative for 18F-FET uptake (SUV, 1.3-1.6). The SUVs of 18F-FDG in SCC were significantly higher (13.0 +/- 9.3) than those of 18F-FET (4.4 +/- 2.2). The ROC analysis showed significantly superior detection of SCC with (18)F-FET PET or 18F-FDG PET than with CT. No significant difference (P = 0.71) was found between 18F-FDG PET and 18F-FET PET. The sensitivity of 18F-FDG PET was 93%, specificity was 79%, and accuracy was 83%. 18F-FET PET yielded a lower sensitivity of 75% but a substantially higher specificity of 95% (accuracy, 90%).


CONCLUSIONS
18F-FET may not replace 18F-FDG in the PET diagnostics of head and neck cancer but may be a helpful additional tool in selected patients, because 18F-FET PET might better differentiate tumor tissue from inflammatory tissue. The sensitivity of 18F-FET PET in SCC, however, was inferior to that of 18F-FDG PET because of lower SUVs.
Pauleit
Dirk
D
Institute of Medicine and Brain Imaging Center West, Research Center Jülich, Jülich, Germany. pauleit@web.de
Zimmermann
Andre
A
Stoffels
Gabriele
G
Bauer
Dagmar
D
Risse
Jörn
J
Flüss
Michael O
MO
Hamacher
Kurt
K
Coenen
Heinz H
HH
Langen
Karl-Josef
KJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018307:Neoplasms, Squamous Cell / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods; D014443:Tyrosine / Q000031:analogs & derivatives*
C117289:O-(2-fluoroethyl)tyrosine; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D014443:Tyrosine