Comparison of MET-PET and FDG-PET for differentiation between benign lesions and malignant tumors of the lung.
ABSTRACT We retrospectively assessed and compared the usefulness of 11C-methionine (MET)-PET with that of 18F-FDG-PET for the differentiation between benign lesions and malignant tumors of the lung.
We examined 101 patients with a suspected lung tumor including 79 patients with primary lung cancer and 22 patients with benign lesions. One hundred and forty PET studies (46 studies with MET-PET and 94 studies with FDG-PET) were performed. Both MET-PET and FDG-PET were performed on 39 patients. The MET-PET was performed 15 minutes after the administration of 67-740 MBq of MET, and FDG-PET 45 minutes after the administration of 30-437 MBq of FDG. The results were then evaluated by the standardized uptake value (SUV).
The MET uptake in lung cancer was 3.69+/-1.22 (n = 37) which was significantly higher than that in benign lesions 1.81+/-1.04 (n = 9) (p < 0.001). The sensitivity, specificity and accuracy of MET-PET were 83.8%, 88.9% and 84.8%, respectively, when 2.66 of SUV was used as the cutoff value. The FDG uptake in lung cancer was 5.94+/-2.89 (n = 75) and was also significantly larger than that in benign lesions 2.46+/-1.01 (n = 19) (p < 0.001). The sensitivity, specificity and accuracy of FDG-PET were 81.3%, 78.9% and 80.9%, respectively (cutoff = 3.20). The MET uptake in the lesions correlated significantly with FDG uptake (r = 0.71, p < 0.001). According to an ROC analysis, the area under the curve for MET-PET (area = 0. 833) was higher than that for FDG-PET (area = 0.828), but the difference was not statistically significant. Furthermore, the combined use of MET-PET and FDG-PET did not improve the diagnostic ability.
In conclusion, both MET-PET and FDG-PET were considered to be equally useful for the differential diagnosis of lung tumors. Furthermore, MET uptake in lung lesions was found to correlate significantly with FDG uptake.
- Imaging Decisions MRI 12/2002; 6(4):26-31.
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ABSTRACT: [(18)F]FDG PET has difficulty distinguishing tumor from inflammation in the clinic because of the same high uptake in nonmalignant and inflammatory tissue. In contrast, amino acid tracers do not accumulate in inflamed tissues and thus provide an excellent opportunity for their use in clinical cancer imaging. In this study, we developed a new amino acid tracer 5-(3-[(18)F]Fluoropropyloxy)-L-tryptophan ([(18)F]-L-FPTP) by two-step reactions and performed its biologic evaluation. [(18)F]-L-FPTP was prepared by [(18)F]fluoropropylation of 5-hydroxy-L-tryptophan disodium salt and purification on C18 cartridges. The biodistribution of [(18)F]-L-FPTP was determined in normal mice and the incorporation of [(18)F]-L-FPTP into tissue proteins was investigated. In vitro competitive inhibition experiments were performed with Hepa1-6 hepatoma cell lines. [(18)F]-L-FPTP PET imaging was performed on tumor-bearing and inflammation mice and compared with [(18)F]-L-FEHTP PET. The overall uncorrected radiochemical yield of [(18)F]-L-FPTP was 21.1±4.4% with a synthesis time of 60min, the radiochemical purity was more than 99%. Biodistribution studies demonstrate high uptake of [(18)F]-L-FPTP in liver, kidney, pancreas, and blood at the early phase, and fast clearance in most tissues over the whole observed time. The uptake studies in Hepa1-6 cells suggest that [(18)F]-L-FPTP is transported by the amino acid transport system B(0,+), LAT2 and ASC. [(18)F]-L-FPTP displays good stability and is not incorporated into proteins in vitro. PET imaging shows that [(18)F]-L-FPTP can be a better potential PET tracer for differentiating tumor from inflammation than [(18)F]FDG and 5-(3-[(18)F]fluoroethyloxy)-L-tryptophan ([(18)F]-L-FEHTP), with high [(18)F]-L-FPTP uptake ratio (2.53) of tumor to inflammation at 60min postinjection. Using [(18)F]fluoropropyl derivatives as intermediates, the new tracer [(18)F]-L-FPTP was achieved with good yield and radiochemical purity, and the biological evaluation results of [(18)F]-L-FPTP showed that it was a hopeful tracer for PET tumor imaging.Nuclear Medicine and Biology 06/2013; · 2.41 Impact Factor
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ABSTRACT: Although positron emission tomography (PET) using [(18)F]-fluoro-2-deoxy-D-glucose ((18)F-FDG) is established as one of the first-choice imaging modalities in the diagnosis of chest malignancies, there are several problems to solve in clinical practice, such as false positive uptake in inflammatory diseases. The aim of this study was to evaluate the clinical usefulness of an amino acid tracer, α-[N-methyl-(11)C]-methylaminoisobutyric acid ((11)C-MeAIB), in the diagnosis of chest malignancies, in combination with (18)F-FDG. Fifty-nine cases (57 patients, 66 ± 12 years old) who consulted to our institution for the wish to receive differential diagnosis of chest diseases were included. Purpose of the studies were as follows: differential diagnosis of newly developed lung nodules, n = 22; newly developed mediastinal lesions, n = 20; and both, n = 17 (including lung cancer: n = 19, lymphoma: n = 1, other cancers: n = 2, sarcoidosis: n = 15, non-specific inflammation: n = 18, other inflammatory: n = 4, respectively). Whole-body static PET or PET/CT scan was performed 20 and 50 min after the IV injection of (11)C-MeAIB and (18)F-FDG, respectively. (11)C-MeAIB uptake of malignant and benign lesions was statistically different both in pulmonary nodules (p < 0.005) and in mediastinal lesions (p < 0.0005). In visual differential diagnosis, (11)C-MeAIB showed higher results (specificity: 73 %, accuracy: 81 %), compared to those in (18)F-FDG (60, 73 %, respectively). In cases of sarcoidosis, (11)C-MeAIB showed higher specificity (80 %) with lower uptake (1.8 ± 0.7) in contrast to the lower specificity (60 %) with higher uptake of (18)F-FDG (7.3 ± 4.5). (11)C-MeAIB PET/CT was useful in the differential diagnosis of pulmonary and mediastinal mass lesions found on CT. (11)C-MeAIB PET or PET/CT showed higher specificity than that of (18)F-FDG PET/CT in differentiating between benign and malignant disease. Our data suggest that the combination of (18)F-FDG and (11)C-MeAIB may improve the evaluation of chest lesions, when CT and (18)F-FDG PET/CT are equivocal.Annals of Nuclear Medicine 07/2013; · 1.41 Impact Factor