Development of Br-labeled amino acid derivative for PET imaging of tumor

新規がん診断用PETイメージング薬剤Br標識アミノ酸誘導体の開発

花岡 宏史*; 渡邉 茂樹; 大島 康宏; 織内 昇*; 石岡 典子; 遠藤 啓吾*

Hanaoka, Hirofumi*; Watanabe, Shigeki; Ohshima, Yasuhiro; Oriuchi, Noboru*; Ishioka, Noriko; Endo, Keigo*

Positron emission tomography (PET) with F-fluorodeoxyglucose (FDG) is widely used for imaging of tumor. However, FDG accumulates not only in the tumor but also in the inflammation or the benign region. Recently, radiolabeled amino acid derivatives, more specific tracer for malignant tumors than FDG, have received attention, and are becoming to use in clinical phase. In this study, amino acid derivative labeled with Br-76 (Br; half-life = 16.1 h), an attractive positron emitter, was prepared and evaluated as a potential PET tracer for imaging tumors. Alpha-methyl phenylalanine (-Me-Phe) was selected as the mother compound and Br was attached to para position of -Me-Phe. Biodistribution studies of Br--Me-Phe in nude mice bearing colorectal cancer cell line, LS-180, showed a marked accumulation in the tumor at 3 h after injection, and resulting in high tumor-to-blood and tumor-to-muscle ratios of 3.94 and 3.51, respectively. Br--Me-Phe PET showed a clear image of the tumor, which was almost same with F-labeled amino acid derivative. These findings indicated that Br--Me-Phe would be a potential tracer for imaging tumor.