Naka Sadahiro, Watanabe Toshimitsu, Kanai Yasukazu, Watabe Tadashi, Tatsumi Mitsuaki, Kato Hiroki, Shimosegawa Eku, Hatazawa Jun
Department of Nuclear Medicine and Tracer Kinetics, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka 565-0871 Japan.
Department of Radiology, Osaka University Hospital, 2-15, Yamadaoka, Suita, Osaka 565-0871 Japan.
Nucl Med Mol Imaging. 2022 Apr;56(2):86-95. doi: 10.1007/s13139-021-00719-1. Epub 2022 Feb 8.
4-Borono-2-[F]fluoro-l-phenylalanine ([F]FBPA) synthesized with [F]F, produced using the O(p, n)F reaction, has been reported for increasing radioactivity. However, a dedicated system and complex procedure is required to reuse the costly [O]O gas; also, the use of [F]F as a labeling agent reduces the labeling rate and radiochemical purity. We developed a stable and practical method for [F]FBPA synthesis by combining [F]F, produced using a [O]O single-use system, and a [F]CHCOOF labeling agent.
The produced [F]F was optimized, and then [F]FBPA was synthesized. For passivation of the target box, 0.5% F was pre-irradiated in argon. Gaseous products were discarded; the target box was filled with [O]O gas, and then irradiated (first irradiation). Then, the [O]O gas was discarded, 0.05-0.08% F in argon was fed into the target box, and it was again irradiated (second irradiation). The [F]F obtained after this was passed through a CHCOONa column, converting it into the [F]CHCOOF labeling agent, which was then used for [F]FBPA synthesis.
The mean amount of as-obtained [F]F was 55.0 ± 3.3 GBq and that of as-obtained [F]CHCOOF was 21.6 ± 1.4 GBq after the bombardment. The radioactivity and the radiochemical yield based on [F]F of [F]FBPA were 4.72 ± 0.34 GBq and 12.2 ± 0.1%, respectively. The radiochemical purity and molar activity were 99.3 ± 0.1% and 231 ± 22 GBq/mmol, respectively.
We developed a method for [F]FBPA production, which is more stable and practical compared with the method using [O]O gas-recycling and [F]F labeling agent.
已报道用[F]F通过O(p, n)F反应合成的4-硼-2-[F]氟-L-苯丙氨酸([F]FBPA)可提高放射性。然而，要重复使用昂贵的[O]O气体需要专用系统和复杂程序；此外，使用[F]F作为标记剂会降低标记率和放射化学纯度。我们通过将使用一次性[O]O系统产生的[F]F与[F]CHCOOF标记剂相结合，开发了一种稳定且实用的[F]FBPA合成方法。
对产生的[F]F进行优化，然后合成[F]FBPA。为使靶盒钝化，在氩气中预辐照0.5%的F。气态产物被丢弃；靶盒充入[O]O气体，然后进行辐照（第一次辐照）。然后，丢弃[O]O气体，将氩气中0.05 - 0.08%的F通入靶盒，并再次进行辐照（第二次辐照）。之后得到的[F]F通过CHCOONa柱，转化为[F]CHCOOF标记剂，然后用于[F]FBPA的合成。
轰击后得到的[F]F的平均量为55.0±3.3 GBq，得到的[F]CHCOOF的平均量为21.6±1.4 GBq。基于[F]F的[F]FBPA的放射性和放射化学产率分别为4.72±0.34 GBq和12.2±0.1%。放射化学纯度和摩尔活度分别为99.3±0.1%和231±22 GBq/mmol。
我们开发了一种[F]FBPA的生产方法，与使用[O]O气体循环和[F]F标记剂的方法相比，该方法更稳定、更实用。
