Supplementary Material for: 18F-FAMT PET Is Useful to Distinguish between Specific Uptake and Nonspecific Uptake Compared to 18F-Flourodeoxyglucose Position Emission Tomography in Esophageal Cancer Patients

<p><b><i>Background:</i></b> L-[3-<sup>18</sup>F]-α-methyltyrosine (<sup>18</sup>F-FAMT) solely accumulates in tumor cells via an amino acid transport system. This selective uptake pattern results in a very high tumor-to-background ratio, enabling clear delineation of the tumor. The purpose of the present study was to assess the significance of <sup>18</sup>F-FAMT PET, which shows little nonspecific uptake compared to <sup>18</sup>F-flourodeoxyglucose position emission tomography (FDG PET) in esophageal cancer patients. <b><i>Methodology:</i></b> PET-CT studies with <sup>18</sup>F-FAMT and <sup>18</sup>F-FDG were performed as part of pretreatment work-up in 82 patients with histologically confirmed esophageal cancer. We evaluated nonspecific uptakes of <sup>18</sup>F-FDG and <sup>18</sup>F-FAMT PET. <b><i>Results:</i></b> The nonspecific uptake of <sup>18</sup>F-FAMT PET was lower than that of <sup>18</sup>F-FDG PET (<i>p = </i>0.282). In the operation group, 26.1% demonstrated nonspecific uptake in <sup>18</sup>F-FDG PET, whereas only 2.38% (1 case) demonstrated nonspecific uptake in <sup>18</sup>F-FAMT PET (<i>p = </i>0.433). In the inoperable group, 47.5% showed nonspecific uptake in <sup>18</sup>F-FDG PET, whereas 5.0% showed nonspecific uptake in <sup>18</sup>F-FAMT PET (<i>p = </i>0.079). <b><i>Conclusion:</i></b> A crucial point for the diagnostic value of PET is distinguishing specific and nonspecific uptake. <sup>18</sup>F-FAMT-PET is a very superior modality with regard to the lower rate of nonspecific uptake in esophageal cancer.</p>