Imaging bone and soft tissue tumors with the proliferation marker [18F]fluorodeoxythymidine.
OBJECTIVE
We have determined the ability of positron emission tomography (PET) with the thymidine analogue 3'-deoxy-3'[18F]fluorothymidine (FLT) to detect manifestation sites of bone and soft tissue tumors, to assess tumor grading, and to differentiate malignant from benign tumors.


METHODS
In this prospective bicenter trial, FLT-PET was done in 22 patients with established or suspected soft or bone tissue lesions. Routine diagnostic procedures included incisional biopsy, magnetic resonance imaging, and/or contrast-enhanced spiral computed tomography in all patients and [18F]fluorodeoxyglucose (FDG)-PET in 15 patients. Forty-five to 60 minutes after i.v. injection of 350 to 425 MBq FLT, emission and transmission scanning was done. Tracer uptake in the tumor was evaluated semiquantitatively by calculation of mean and maximum standardized uptake values (FLT-SUV) and compared with respective values of FDG. Results were correlated to histopathology and tumor grading.


RESULTS
FLT-PET detected all malignant bone or soft tissue tumors (17 of 17). Mean FLT-SUV in benign lesions was 0.7 (range, 0.3-1.3), and 1.3 in low-grade sarcoma (grade 1; range, 1.0-1.6), 4.1 (range, 2.2-6.0; P = 0.002) and 6.1 (range, 2.5-8.3; P = 0.001) in grade 2 and grade 3 tumors, respectively. FLT but not FDG uptake correlated significantly with tumor grading (r = 0.71 versus r = 0.01), and a cutoff value of 2.0 for FLT-SUV discriminated between low- and high-grade tumors.


CONCLUSIONS
In this clinical study, the proliferation marker FLT was suitable for imaging malignant bone or soft tissue tumors. FLT but not FDG uptake correlated significantly with the tumor grade, suggesting FLT as superior PET tracer for noninvasive grading of sarcomas.
Buck
Andreas K
AK
Department of Nuclear Medicine, Technische Universitat Munchen, Munich, Germany. andreas.buck@tum.de
Herrmann
Ken
K
Büschenfelde
Christian Meyer Zum
CM
Juweid
Malik E
ME
Bischoff
Mark
M
Glatting
Gerhard
G
Weirich
Gregor
G
Möller
Peter
P
Wester
Hans-Jürgen
HJ
Scheidhauer
Klemens
K
Dechow
Tobias
T
Peschel
Christian
C
Schwaiger
Markus
M
Reske
Sven N
SN
D000293:Adolescent; D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D013936:Thymidine / Q000493:pharmacokinetics
D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; D013936:Thymidine