Assessment of [18F]-fluoroacetate PET/CT as a tumor-imaging modality: preclinical study in healthy volunteers and clinical evaluation in patients with liver tumor

Although [F-18]-FDG is a useful oncologic PET tracer, FDG uptake is known to be low in a certain type of hepatocellular carcinoma (HCC). [F-18]-fluoroacetate (F-18-FACE) is an [F-18] fluorinated acetate, which is known to be converted into fatty acids, incorporated in membrane and is expected to be a promising oncologic PET tracer. The aim of this study was to evaluate the usefulness of F-18-FACE as an oncologic PET tracer in preclinical study in healthy volunteers and in patients with liver tumors. Twenty-four healthy volunteers (age 48.2 +/- A 12.9 years old; 15 male and 9 female) and ten patients with liver tumor (age 72.1 +/- A 7.0 years old; 6 male and 4 female) were included. We performed whole-body static PET/CT scan using F-18-FACE (n = 34) and F-18-FDG (n = 5 for volunteers, n = 8 for patients) on each day, respectively. Qualitative analysis and quantitative analysis of tumors (5 HCCs, 1 cholangiocellular carcinoma, 4 metastatic tumors from colon cancer and P-NET) were performed using SUVmax and tumor-to-normal liver ratio (TNR). In healthy volunteers, F-18-FACE was metabolically stable in vivo and its biodistribution was almost similar to blood pool, basically uniformly independent of age and gender during PET scan time (up to 3 h). Normal physiological uptake of F-18-FACE at each organ including liver (SUVmean 1.8 +/- A 0.2) was lower than that of blood pool (SUVmean 2.3 +/- A 0.3) at 1 h after injection. Chronic inflammatory uptake around femur of post-operative state of femoral osteotomy and faint uptake of benign hemangioma were observed in a case of healthy volunteer. F-18-FACE (SUVmax 2.7 +/- A 0.6, TNR 1.5 +/- A 0.4) of liver tumors was significantly lower than those of F-18-FDG uptake (6.5 +/- A 4.2, 2.6 +/- A 1.7, respectively). In qualitative analysis, F-18-FDG was positive in 4 tumors (3 HCCs, 1 CCC) and negative in the other 6 tumors, while F-18-FACE was also positive in 4 tumors which were the same tumors with positive F-18-FDG uptake. Biodistribution of F-18-FACE was appropriate for oncologic imaging. Tumor F-18-FACE uptake was positive in four patients with HCC and CCC, but the uptake pattern was similar to F-18-FDG. Further evaluation was needed.