%0 Journal Article %A Shuntaro Oka %A Masaru Kanagawa %A Masahiro Ono %A Yoshihiro Doi %A David Schuster %A Mark Goodman %A Hirokatsu Yoshimura %T Feasibility of Fluciclovine (FACBC) for bone metastasis diagnosis in prostate and breast cancer: Evaluation by using triple-tracer autoradiography with 14C-Fluciclovine/3H-FDG/99mTc-HMDP in rat osteolytic/osteoblastic bone metastasis models %D 2016 %J Journal of Nuclear Medicine %P 1360-1360 %V 57 %N supplement 2 %X 1360Objectives Most patients with advanced prostate cancer (PCa) or breast cancer (BRCa) have mixed osteolytic and osteoblastic bone metastases. Accurate diagnosis of bone metastasis is important in planning therapeutic strategies for PCa and BRCa. 18F-Fluciclovine (anti-18F-FACBC; trans-1-amino-3-18F-fluorocyclobutanecarboxylic acid) is a positron emission tomography (PET) tracer for diagnosing PCa. In this study, we investigated the potential of 18F-Fluciclovine in helping to visualize osteolytic and osteoblastic bone metastases, with histologic analyses, and compared it with that of 2-deoxy-2-fluoro-D-glucose (FDG) and hydroxymethylene diphosphonate (HMDP) by using triple-tracer autoradiography (ARG) in rat models.Methods We performed triple-tracer ARG with 14C-Fluciclovine, 3H-FDG, and 99mTc-HMDP in a BRCa osteolytic model, a PCa osteoblastic model, and a new bone formation model formed by drilling holes in the cortical bone of the tibia in rats, to compare the distribution of each tracer visually in the identical lesions. The osteolytic and osteoblastic lesions were in the tibia and/or femur. Accumulation of each tracer in the lesions, as well as new bone formation areas, was evaluated with the target-to-background (normal area of bone marrow) (T/B) ratio. Moreover, these lesions were analyzed histologically.Results In the BRCa osteolytic bone metastasis model, 14C-Fluciclovine accumulated in the lesions with osteoclasts; the distribution patterns were similar to those of 3H-FDG, although the average T/B ratio of 3H-FDG was higher than that of 14C-Fluciclovine. Some lesions showed differential distribution patterns of both tracers; lesions with low 14C-Fluciclovine and high 3H-FDG accumulation tended to have infiltrated inflammatory cells. Although 99mTc-HMDP did not accumulate in the tumor itself, it showed a remarkable accumulation at the edges of the tumors that invaded into cortical bone or in metastatic sites with microcalcification. In the PCa osteoblastic bone metastasis model, there were two distribution patterns of the tracers in tumor metastatic sites: the accumulation of both 14C-Fluciclovine and 3H-FDG, but not 99mTc-HMDP; and that of all three tracers. Histologic analyses demonstrated that metastatic sites with the first pattern were mainly composed of tumor cells, while those with the second pattern were composed of tumor cells and osteoid tissues, indicating new bone formation; that is, osteoblastic lesions. In the new bone formation (non-tumor) model only 99mTc-HMDP, and not 14C-Fluciclovine or 3H-FDG, accumulated intensely in areas of active bone formation.Conclusions 18F-Fluciclovine-PET can help visualize tumor cell components in osteolytic and early-stage osteoblastic bone metastatic lesions. The accumulation of 14C-Fluciclovine and 3H-FDG in osteoblastic lesions indicated the existence of tumor cells since significant activity was not present with these radiotracers in the new bone formation (non-tumor) model. Furthermore, we speculate that false positive imaging due to tracer accumulation will be lower in 18F-Fluciclovine-PET than in 18F-FDG-PET, because in our study, the accumulation of 14C-Fluciclovine was lower than that of 3H-FDG in the inflamed tissues. On the other hand, 99mTc-HMDP can be predominantly used for detecting advanced osteoblastic lesions (sclerotic bone lesions). Thus, using both 18F-Fluciclovine and 99mTc-HMDP would help in more accurately diagnosing bone metastases. %U