We evaluated the diagnostic usefulness of 3′-deoxy-3′-[18F]fluorothymidine (FLT) compared with 2-[18F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in recurrent brain tumors.
Twenty patients with suspected recurrence after surgical removal of primary tumors were studied. The uptake was assessed visually and quantified by standardized uptake value (SUV) and SUV ratio of tumor to white matter, tumor to gray matter, and tumor to normal tissue. Final diagnoses were made by histopathology or clinical and radiological follow-up.
Of 20 lesions, 15 were recurrences. 3′-Deoxy-3′-[18F]fluorothymidine PET showed high diagnostic sensitivity (15/15 [100%]) and moderate specificity (3/5 [60.0%]). 2-[18F]fluoro-2-deoxy-D-glucose PET showed moderate diagnostic sensitivity (11/15 [73.3%]) and specificity (4/5 [80%]). All of 4 recurrent tumors without FDG uptake showed FLT uptake. Tumor-to-normal tissue ratios (3.99 ± 1.72) of recurrent tumors on FLT PET were significantly higher than tumor-to-white matter ratios (1.96 ± 0.93) and tumor-to-gray matter ratios (1.32 ± 0.33) on FDG PET (P < 0.001), although SUVs (0.62 ± 0.32) of recurrent tumors on FLT PET were lower than those (2.44 ± 1.02) on FDG PET (P < 0.001).
3′-Deoxy-3′-[18F]fluorothymidine PET has a high sensitivity but a lower specificity, which has a limited role in the diagnosis of recurrent brain tumors as a complimentary tool of magnetic resonance imaging.
From the *Department of Nuclear Medicine, Kyung Hee University Hospital, Seoul; Departments of †Neurosurgery, and ‡Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
Received for publication June 19, 2011; accepted August 24, 2011.
Reprints: Jae Seung Kim, MD, PhD, Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Poongnap 2-dong, Songpa-gu, Seoul, South Korea (e-mail: firstname.lastname@example.org).
This study was supported by a grant from the Korea Healthcare Technology R&D Project, Ministry of Health, Welfare and Family Affairs, Republic of Korea (A060775).
The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.