PET imaging of NET expressing tumors using Br-MBBG

Br-MBBGを用いたNET発現腫瘍のPETイメージング

渡邉 茂樹; 花岡 宏史*; Liang, J. X.; 渡辺 智; 飯田 靖彦*; 遠藤 啓吾*; 石岡 典子

Watanabe, Shigeki; Hanaoka, Hirofumi*; Liang, J. X.; Watanabe, Satoshi; Iida, Yasuhiko*; Endo, Keigo*; Ishioka, Noriko

Meta-iodobenzylguanidine (MIBG) labeled with I or I has been widely used for the diagnosis and radiotherapy of norepinephrine transporter (NET)-expressing tumors. In this study, a positron emitter Br labeled meta-bromobenzylguanidine (MBBG) was synthesized and evaluated as a potential PET tracer for imaging NET-expressing tumors. Results: After separation, we prepared 250-550 MBq of no-carrier-added Br. Br labeled MBBG was synthesized with 20-50% of labeling efficiency. In biodistribution studies, MBBG showed high accumulation in tumor and the tumor-to-blood ratio reached as high as 54.4 at 3 h after administration. Tumor uptake of MBBG correlated very well with that of MIBG (r = 0.997), but not with FDG. MBBG-PET showed a very clear image of the transplanted tumor with high sensitivity, and the visualized lesion was different from that by FDG-PET. Conclusion: Br-MBBG showed high tumor accumulation which correlated very well with that of MIBG, and provided a clear PET image. These results indicated that Br labeled MBBG would be a potential PET tracer for imaging NET-expressing tumors, and could provide useful information for determining the indications for MIBG therapy.