Detection of malignant tumors: whole-body PET with fluorine 18 alpha-methyl tyrosine versus FDG--preliminary study.

Purpose: To compare the diagnostic potential of whole-body positron emission tomography (PET) with fluorine 18 alpha-methyl tyrosine (FMT) with that of whole-body PET with 2-[fluorine 18]fluoro-2-deoxy-D-glucose (FDG).
Materials and Methods: Nineteen patients with or suspected of having malignant tumors and five healthy volunteers underwent whole-body PET with FMT and FDG.
Results: In comparison with FDG uptake, FMT uptake was significantly less in the brain, heart, lung, liver, and spine. On a lesion-by-lesion basis, the sensitivity of whole-body FMT PET for depicting malignant tumors was inferior to that of whole-body FDG PET, but this difference was not statistically significant (74% [26 of 35 lesions] vs 91% [32 of 35 lesions], P >.05). The positive predictive value of FMT PET was superior to that of FDG PET (87% [26 of 30 lesions] vs 63% [32 of 51 lesions], P <.001). The difference in uptake between benign and malignant lesions was significant with FMT PET (mean +/- SD, 1.64 +/- 0.96 vs 0.79 +/- 0.23; P <.001) but not with FDG PET (5.02 +/- 3.56 vs 4.02 +/- 2.90, P >.05).
Conclusion: Whole-body FMT PET is clinically useful in the diagnosis of malignant tumors and may be effective in the depiction of primary and metastatic lesions in the cardiac region or in the brain.