Improved Stability and Practicality for Synthesis of 4-Borono-2-[18F]fluoro-l-phenylalanine by Combination of [18O]O2 Single-Use and [18F]CH3COOF Labeling Agents

• Published in: Nuclear medicine and molecular imaging Vol. 56; no. 2; pp. 86 - 95
• Main Authors: Naka, Sadahiro, Watanabe, Toshimitsu, Kanai, Yasukazu, Watabe, Tadashi, Tatsumi, Mitsuaki, Kato, Hiroki, Shimosegawa, Eku, Hatazawa, Jun
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01-04-2022; Springer Nature B.V; 대한핵의학회
• Subjects: Argon; Cardiology; Imaging; Irradiation; Labeling; Medicine; Medicine & Public Health; Nuclear Medicine; Oncology; Original; Original Article; Orthopedics; Phenylalanine; Purity; Radioactivity; Radiochemistry; Radiology; Sodium acetate; 방사선과학; O]O; F]FBPA; Single-use; gas; [; COOF; F]CH; F]F; Boron neutron capture therapy
• ISSN: 1869-3474; 1869-3482
• DOI: 10.1007/s13139-021-00719-1

Purpose
4-Borono-2-[
18
F]fluoro-
l
-phenylalanine ([
18
F]FBPA) synthesized with [
18
F]F
2
, produced using the
18
O(p, n)
18
F reaction, has been reported for increasing radioactivity. However, a dedicated system and complex procedure is required to reuse the costly [
18
O]O
2
gas; also, the use of [
18
F]F
2
as a labeling agent reduces the labeling rate and radiochemical purity. We developed a stable and practical method for [
18
F]FBPA synthesis by combining [
18
F]F
2
, produced using a [
18
O]O
2
single-use system, and a [
18
F]CH
3
COOF labeling agent.
Methods
The produced [
18
F]F
2
was optimized, and then [
18
F]FBPA was synthesized. For passivation of the target box, 0.5% F
2
was pre-irradiated in argon. Gaseous products were discarded; the target box was filled with [
18
O]O
2
gas, and then irradiated (first irradiation). Then, the [
18
O]O
2
gas was discarded, 0.05–0.08% F
2
in argon was fed into the target box, and it was again irradiated (second irradiation). The [
18
F]F
2
obtained after this was passed through a CH
3
COONa column, converting it into the [
18
F]CH
3
COOF labeling agent, which was then used for [
18
F]FBPA synthesis.
Results
The mean amount of as-obtained [
18
F]F
2
was 55.0 ± 3.3 GBq and that of as-obtained [
18
F]CH
3
COOF was 21.6 ± 1.4 GBq after the bombardment. The radioactivity and the radiochemical yield based on [
18
F]F
2
of [
18
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.
Conclusion
We developed a method for [
18
F]FBPA production, which is more stable and practical compared with the method using [
18
O]O
2
gas-recycling and [
18
F]F
2
labeling agent.