{ "abstract": "Background\n\n¹⁸F-Labeled (E)-1-fluoro-3-((2-(4-(5-(methylamino)pyrazin-2-yl)but-1-en-3-yn-1-yl)benzo[d]thiazol-6-yl)oxy)propan-2-ol ([¹⁸F]SPAL-T-06) and (E)-1-fluoro-3-((2-(4-(6-(methylamino)pyridine-3-yl)but-1-en-3-yn-1-yl)benzo[d]thiazol-6-yl)oxy)propan-2-ol ([¹⁸F]C05-05) are positron emission tomography (PET) imaging agents for α-synuclein pathologies. Recently, we demonstrated the utility of PET imaging with [¹⁸F]SPAL-T-06 for α-synuclein pathologies in patients with multiple system atrophy and with [¹⁸F]C05-05 for α-synuclein pathologies in Parkinson's disease and related disorders. In this study, to establish [¹⁸F]SPAL-T-06 and [¹⁸F]C05-05 as PET radiopharmaceuticals for clinical investigations, we developed routine radiosynthetic procedures using an ¹⁸F-labeling synthesizer and performed quality control (QC) testing of these two PET radiopharmaceuticals.Results\n\n[¹⁸F]SPAL-T-06 and [¹⁸F]C05-05 were synthesized by direct ¹⁸F-fluorination of their respective tetrahydropyranyl-protected tosylated precursors, followed by deprotection, using an ¹⁸F-labeling synthesizer. The non-decay-corrected radiochemical yields of [¹⁸F]SPAL-T-06 and [¹⁸F]C05-05 from ¹⁸F⁻ at the end of synthesis (EOS) were 11 ± 4.6% (n = 19) and 20 ± 6.8% (n = 37), respectively. The radiochemical purities of both PET radiopharmaceuticals exceeded 99%. The molar activities of each PET radiopharmaceutical at EOS exceeded 68 GBq/µmol, and the total synthesis times were within 100 min after irradiation. In addition, [¹⁸F]SPAL-T-06 and [¹⁸F]C05-05 were efficiently separated from byproducts using a semi-preparative high-performance liquid chromatography system. All QC results for the two PET radiopharmaceuticals complied with in-house QC and quality assurance specifications. The stabilities of the two PET radiopharmaceuticals were evaluated under standard fluorescent light in a general laboratory environment and under UV-cutoff light in a natural light-shielded environment. After 10 min of exposure to the standard fluorescent light, the radiochemical purity of each tracer decreased to approximately 86%. In contrast, the radiochemical purity of each tracer exceeded 99% after 60 min under UV-cutoff light in a natural light-shielded environment.Conclusions\n\nWe successfully prepared two PET radiopharmaceuticals, [¹⁸F]SPAL-T-06 and [¹⁸F]C05-05, for clinical investigation. The radiosynthesis and QC findings provide a practical basis for establishing standardized production procedures and facilitating technology transfer to other PET centers. In particularly, all post-deprotection radiosynthesis steps and QC testing for [¹⁸F]SPAL-T-06 and [¹⁸F]C05-05 should be performed under UV-cutoff light in a natural light-shielded environment to prevent photoisomerization.", "abstract_shown": true, "affiliations": [ "Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.", "SHI Accelerator Service Ltd., 7-1-1 Nishigotanda, Shinagawa-ku, Tokyo, 141-0032, Japan.", "Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan. kawamura.kazunori@qst.go.jp.", "Tokyo Nuclear Services Co., Ltd., 1-3-5 Taito, Taito-ku, Tokyo, 110-0016, Japan.", "Advanced Neuroimaging Center, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.", "Neuroetiology and Diagnostic Science, Osaka Metropolitan University Graduate School of Medicine, 1-4-3 Asahi-Machi, Abeno-ku, Osaka, 545-8585, Japan." ], "article_type": "research article", "arxiv": null, "author_total": 16, "authors": [ { "affs": [ 0 ], "name": "Hiroki Hashimoto" }, { "affs": [ 0, 1 ], "name": "Takayuki Ohkubo" }, { "affs": [ 2 ], "name": "Kazunori Kawamura", "orcid": "0000-0001-6786-678X" }, { "affs": [ 0, 3 ], "name": "Tomoya Fujishiro" }, { "affs": [ 0, 3 ], "name": "Daisuke Arashi" }, { "affs": [ 0, 3 ], "name": "Tatsuto Sato" }, { "affs": [ 0, 3 ], "name": "Takeru Seki" }, { "affs": [ 0, 3 ], "name": "Masatoshi Muto" }, { "affs": [ 0, 1 ], "name": "Kaito Tsukagoe" }, { "affs": [ 0, 1 ], "name": "Masanao Ogawa" }, { "affs": [ 0, 1 ], "name": "Yusuke Kurihara" }, { "affs": [ 0, 1 ], "name": "Nobuki Nengaki" }, { "affs": [ 0 ], "name": "Wakana Mori" }, { "affs": [ 0 ], "name": "Masayuki Fujinaga" }, { "affs": [ 4, 5 ], "name": "Makoto Higuchi" }, { "affs": [ 0 ], "name": "Ming-Rong Zhang" } ], "bibtex": "https://research.draconitic.com/paper/ddyd12vmdmq4s.bib", "cited_by": 0, "doi": "10.1186/s41181-026-00480-w", "fulltext_url": "https://europepmc.org/articles/PMC13677666", "id": "ddyd12vmdmq4s", "issns": [ "2365-421X" ], "landing_url": "https://europepmc.org/article/MED/42894080", "language": "eng", "licence": "CC-BY", "licence_label": "CC BY", "licence_source": "article", "licence_url": "https://creativecommons.org/licenses/by/4.0/", "metadata_licence": null, "native_subjects": [ [ "lcc", "R895-920" ], [ "lcc", "RM1-950" ], [ "openalex", "2741|Radiopharmaceutical Chemistry and Applications" ] ], "openalex": "W7170185910", "pdf_url": "https://europepmc.org/articles/PMC13677666?pdf=render", "pmcid": "PMC13677666", "pmid": "42894080", "published": "2026-07-01", "publisher": "SpringerOpen", "ris": "https://research.draconitic.com/paper/ddyd12vmdmq4s.ris", "sources": [ { "first_seen": "2026-10-30T12:19:42Z", "native_id": "MED:42894080", "source": "europepmc", "url": "https://europepmc.org/article/MED/42894080" }, { "first_seen": "2026-10-30T13:46:32Z", "native_id": "4755cad40f064509b629f9d3e21be0cb", "source": "doaj", "url": "https://doi.org/10.1186/s41181-026-00480-w" } ], "subjects": [ { "field": "medicine", "origin": "openalex:2741|Radiopharmaceutical Chemistry and Applications", "subfield": "imaging" } ], "title": "Radiosynthesis and quality control testing of two ¹⁸F-labeled radiopharmaceuticals for α-synuclein imaging in clinical investigations.", "title_text": "Radiosynthesis and quality control testing of two ¹⁸F-labeled radiopharmaceuticals for α-synuclein imaging in clinical investigations.", "type": "peer-reviewed", "updated_at": "2026-10-30T13:46:32Z", "url": "https://research.draconitic.com/paper/ddyd12vmdmq4s", "venue": "EJNMMI radiopharmacy and chemistry", "versions": [] }