Preliminary evaluation of L-[F-18]-alpha-methyl tyrosine PET/CT in the differential diagnosis of maxillofacial tumor.

Objectives FDG-PET is widely used in the diagnosis of cancer and it is useful in the evaluation of malignancy. To improve the low specificity of FDG-PET, L-[3-F-18]-α–methyl tyrosine (FMT) which is transported into cancer cell by L-type amino acid transporter (LAT1) has been developed in our institute. In this study, the usefulness of FMT-PET for the diagnosis of maxillofacial tumor was compared with FDG-PET.

Methods Thirty-four patients with maxillofacial tumor were enrolled and PET studies with FMT and FDG were performed. Results of both PET studies were analyzed to determine diagnostic accuracy and compared each other. Maximum standardized uptake value (SUV) of FMT and FDG was calculated for the objective comparison and statistical analysis of the difference of SUV in malignant and benign groups was performed.

Results Average SUV of FDG and FMT of were 8.51+/-3.87 and 2.78+-1.68, respectively and FDG showed significantly higher SUV (p<0.01). Comparing SUV of benign (n=8) and malignant (n=26) groups, malignant group showed significantly higher SUV in both FDG (6.22+/-3.26 vs. 9.21+/-3.82, p=0.02) and FMT (1.9+/-1.30 vs. 3.05+/-1.71, p=0.03). In qualitative analysis of each PET image, FMT-PET showed relatively lower false-positive uptake in the maxillofacial region than FDG-PET.

Conclusions Our current study suggests the comparable usefulness of FMT-PET to FDG-PET in the differential diagnosis of maxillofacial tumors and in future contribution of FMT-PET with higher specificity to increase the diagnostic accuracy is warranted.