Higaki, Shogo

Higaki, Shogo Ph.D.
Assistant Professor

Graduate School of Science
Radiation Protection Supervisor

Areas of expertise
Radiochemistry, Radiation safety management, Environmental Chemistry

Description of your research

Radiochemistry and radiation safety management as a basis for using radiation

The use of radiation has some negative aspects, such as a nuclear power plant accident. However, radiation is beneficial in many ways. We are conducting research from a radiochemical approach to make more effective, safer, and more rational use of radiation. For example, iodine-131 is used in nuclear medicine for the diagnosis and treatment of thyroid cancer, but the concentration limit of drain water that can be released into the general wastewater is extremely low, and its half-life (8 days) is rather long, so the frequency of treatment in hospitals cannot be increased. The frequency of treatment may be increased by collecting and keeping iodine-131 from the effluent. We are working on research to find suitable substances and conditions for collection. And we also develop educational and training materials that contribute to the essential improvement of radiation safety.

Behavior and removal of radionuclides dispersed by the FDNPP accident

Since immediately after the TEPCO's Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011, we have been working on clarifying the behavior of radioactive materials dispersed into the environment. For example, we have investigated the possibility of internal exposure caused by the re-diffusion of radioactive cesium into the atmosphere by so-called "cesium pollen," which has become a social concern, and inhalation by the public. We have clarified the impact of contaminated sand and dust is greater than that of pollen by measurements of face masks of citizens who have lived in the Fukushima prefecture. We are also conducting research on the behavior and distribution of insoluble radioactive cesium-containing microparticles (CsMP) and the treatment of contaminated water generated at the FDNPP site.
In this research, we aim to make the results immediately useful to the public and contribute to the restoration of the environment to a safe and secure situation.

Figure 1. An optical microscope image of cedar pollen (indicated by the arrow) collected on filter paper and stained with iodine, which adhered to a mask actually worn. The white line in the lower right corner indicates a size of 100 micrometers.
Figure 2. A composite image of the imaging plate image of a mask actually worn by a subject and an image of a radioactive cesium source adhered to the mask, along with an enlarged photograph of that area. The red line in the lower right corner of each photograph indicates a size of 50 micrometers.

Competitive research funds related to this research

  • 科研費 基盤研究(B)
  • 科研費 基盤研究(C)
  • 公益財団法人放射線影響協会 平成29年度研究奨励助成金
    「一般市民に低線量内部被ばくを及ぼしうる放射性セシウム中の不溶性粒子存在度の解析」(研究代表者)、研究期間: 2018年4月-2021年3月
  • 放射線災害・医科学研究拠点 共同利用・共同研究
    「環状オリゴ糖を用いた新規放射性ヨウ素回収・保持システム開発」(研究分担者)、研究期間: 2016年6月-

List of publications on radiation research

  1. Molecular geochemistry of radium: a key to understanding cation adsorption reaction on clay minerals
    A. Yamaguchi, Y. Kurihara, K. Nagata, K. Tanaka, S. Higaki, T. Kobayashi, H. Tanidai, Y. Ohara, K. Yokoyama, T. Yaita, T. Yoshimura, M. Okumura, and Y. Takahashi
    Journal of Colloid And Interface Science661, 317-332, doi: 10.1016/j.jcis.2024.01.120 (2024). 
  2. Feasibility of treatment agents in radioactive iodine separation from waste liquids
    M. Hirota, S. Higaki, Y. Ishida, D. Nakata, K. Terao and S. Ito
    Health Physics, doi: 10.1097/HP.0000000000001780 (2024). 
  3. Radiocesium-bearing microparticles found in dry deposition fallout samples immediately after the Fukushima nuclear accident in the Kanto region, Japan
    Y. Takaku, S. Higaki*, M. Hirota and H. Kagi
    Scientific Reports13, 21826, doi: 10.1038/s41598-023-49158-2 (2023). 
  4. The discovery of radiocesium-bearing microparticles directly delivered to a person in Tokyo as a result of the Fukushima Daiichi Nuclear Disaster
    S. Higaki*
    Health Physics125(5), 325-331, doi:10.1097/HP.0000000000001719 (2023).
  5. Associations between Sperm Mitochondrial DNA Copy Number and Concentrations of Urinary Cadmium and Selenium
    C. R. Aisyah, Y. Mizuno, M. Masuda, T. Iwamoto, K. Yamasaki, M. Uchida, F. Kariya, S. Higaki, S. Konishi
    Biological Trace Element Research doi:10.1007/s12011-023-03868-w (2023).
  6. Radiocesium-bearing microparticles discovered on masks worn during indoor cleaning
    S. Higaki*, H. Yoshida-Ohuchi and N. Shinohara
    Scientific Reports13, 10008, doi:10.1038/s41598-023-37191-0 (2023).
  7. Reduction of thyroid radioactive iodine exposure by oral administration of cyclic oligosaccharides
    K. Nishi†, M. Hirota†, S. Higaki†, S. Shiraishi, T. Kudo, N. Matsuda and S. Ito
    †These authors contributed equally to this work. 
    Scientific Reports13 6979, doi:10.1038/s41598-023-34254-0 (2023).
  8. Application of liquid scintillation light guide (LSLG) to scattered X-ray measurement from dental panoramic radiography system
    K. Nomura, M. Takahashi, T. Fujibuch, Y. Koike, M. Hara, S. Higaki, I. Kobayashi and S. Yoshino
    Applied Radiation and Isotopes194, 110720, doi:j.10.1016/apradiso.2023.110720 (2023).
  9. Distinction of Migration of Strontium-90 and Cesium-137 for Fukushima Soil and Sediment following the Fukushima Accident
    W. C. Bekelesi, T. Basuki, S. Higaki and S. Nakashima
    Radiation Safety Management21, 26-35, doi:10.12950/rsm.220527 (2022).
  10. 福島第一原子力発電所事故後に富士山で採取された野生食用きのこ3種の方位別および標高別の放射性セシウム濃度
    後藤康彦、桧垣正吾、柴田 尚、保坂健太郎
    日本菌学会会報63(2), 53-58, doi:10.18962/jjom.jjom.R3-12 (2022).
  11. A preliminary biodistribution study of [99mTc]sodium pertechnetate prepared from an electron linear accelerator and activated carbon-based 99mTc generator
    J. Jang, Y. Kumakura, K. Tatenuma, A. N. Ozeki, Y. Wada, N. Akimitsu, A. Tsuguchi, H. Kikunaga, S. Higaki and M. Uesaka
    Nuclear Medicine and Biology110-111, 1-9 (2022).
  12. 高吸水性ポリマーを用いたトリチウム含有処理水の保管・処理およびセシウムとの分離方法の基礎的検討
    環境放射能除染学会誌10(1), 17-25 (2022).
  13. Effects of 2-hydroxypropyl α-cyclodextrin on the radioactive iodine sorption on activated carbon
    M. Hirota, S. Higaki, S. Ito, Y. Ishida and K. Terao
    Journal of Radioanalytical and Nuclear Chemistry328, 659–667 doi:10.1007/s10967-021-07672-5 (2021). 
  14. First isolation and analysis of caesium-bearing microparticles from marine samples in the Pacific coastal area near Fukushima Prefecture
    H. Miura, T. Ishimaru, Y. Ito, Y. Kurihara, S. Otosaka, A. Sakaguchi, K. Misumi, D. Tsumune, A. Kubo, S. Higaki, J. Kanda, and Y. Takahashi
    Scientific Reports11 5664, doi:10.1038/s41598-021-85085-w (2021). 
  15. Characterization of two types of cesium-bearing microparticles emitted from the Fukushima accident via multiple synchrotron radiation analyses
    H. Miura, Y. Kurihara, M. Yamamoto, A. Sakaguchi, N. Yamaguchi, O. Sekizawa, K. Nitta, S. Higaki, D. Tsumune, T. Itai, and Y. Takahashi
    Scientific Reports,  10, 11421, doi:10.1038/s41598-020-68318-2 (2020).
  16. Isotopic ratios of uranium and caesium in spherical radioactive caesium-bearing microparticles derived from the Fukushima Dai-ichi Nuclear Power Plant
    Y. Kurihara, N. Takahata, T. D. Yokoyama, H. Miura, Y. Kon, T. Takagi, S. Higaki, N. Yamaguchi, Y. Sano, and Y. Takahashi
    Scientific Reports,  10, 3281, doi:10.1038/s41598-020-59933-0 (2020).
  17. Discovery of radiocesium-bearing particles in masks worn by members of the public in Fukushima in Spring 2013
    S. Higaki*, Y. Kurihara and Y. Takahashi
    Health Physics118(6), 656-663, doi: 10.1097/HP.0000000000001148 (2020).
  18. Report of the Japan Health Physics Society Ad hoc Working Group for the Plutonium Intake Accident
    S. Iwai, M. Sasaki, S. Higaki, H. Yamanishi and M. Kai
    Journal of Radiological Protection, 39(4), 1092-1104, doi:10.1088/1361-6498/ab26e1 (2019).
    JAEA大洗プルトニウム汚染事故ワーキンググループ、岩井 敏、佐々木道也、桧垣正吾、山西弘城、甲斐倫明
    保健物理, 53(4), 271-282, doi: 10.5453/jhps.53.271 (2019).
  19. Radioactive iodine volatilization inhibition effect of cyclodextrin
    M. Hirota, S. Higaki, S. Ito, Y. Ishida, and K. Terao
    Journal of Radioanalytical and Nuclear Chemistry, 320(3), 621-625, doi: 10.1007/s10967-019-06504-x (2019).
  20. プルトニウム摂取事故に関する日本保健物理学会ワーキンググループ活動報告
    JAEA大洗プルトニウム汚染事故ワーキンググループ、岩井 敏、佐々木道也、桧垣正吾、山西弘城、甲斐倫明
    保健物理 53(4), 271-282, doi: 10.5453/jhps.53.271 (2019).
  21. スウェーデンにおける短寿命α線放出核種の放射線管理の実例
    桧垣 正吾*
    日本放射線安全管理学会誌 17(1), 29-33, doi:10.11269/jjrsm.17.29 (2018).
  22. Discovery of radiocesium-bearing microparticles in river water and their influence on the solid-water distribution coefficient (Kd) of radiocesium in the Kuchibuto River in Fukushima 
    H. Miura, Y. Kurihara, A. Sakaguchi, K. Tanaka, N. Yamaguchi, S. Higaki and Y. Takahashi 
    Geochemical Journal 52, doi:10.2343/geochemj.2.0517 (2018).
  23. Discovery of non-spherical heterogeneous radiocesium-bearing particles not derived from Unit 1 of the Fukushima Dai-ichi Nuclear Power Plant, in residences five years after the accident
    S. Higaki*, Y. Kurihara, H. Yoshida, Y. Takahashi and N. Shinohara
    Journal of Environmental Radioactivity 177, 65-70, doi:10.1016/j.jenvrad.2017.06.006 (2017).
  24. 貯蔵能力を超えた非密封線源の保管から明らかになった潜在的な放射線管理の不備
    桧垣 正吾*、小坂 尚樹
    日本放射線安全管理学会誌 15(2), 173-179, doi:10.11269/jjrsm.15.173 (2016).
  25. 「福島第一原子力発電所事故に伴い環境中に放出された放射性物質への対応一文化財の放射線対策と除染の考え方一」
    佐野 千絵、北野 信彦、早川 典子、杉崎 佐保恵、松田 隆嗣、伊藤 匡、桧垣 正吾、久保 謙哉、石崎 武志
    文化財保存修復学会誌 58, 17-37 (2015).
  26. Quantitation of Japanese cedar pollen and radiocesium adhered to nonwoven fabric masks worn by the general population
    S. Higaki*, H. Shirai, M. Hirota, E. Takeda, Y. Yano, A. Shibata, Y. Mishima, H. Yamamoto and K. Miyazawa
    Health Physics 107(2), 117-134, doi:10.1097/HP.0000000000000078 (2014)
  27. 東京大学アイソトープ総合センターにおける廃棄業の概要と事業所の廃止
    桧垣 正吾*、小坂 尚樹、野川 憲夫
    日本放射線安全管理学会誌 13(1), 55-61, doi:10.11269/jjrsm.13.55 (2014)
  28. Radiocesium distribution in bamboo shoots after the Fukushima nuclear accident
    T. Higaki, S. Higaki, M. Hirota and S. Hasezawa
    PLoS ONE 9(5), e97659, doi:10.1371/journal.pone.0097659 (2014)
  29. Investigation of contamination in spinach collected immediately following the Fukushima Daiichi nuclear disaster
    M. Hirota, S. Higaki, T. Higaki and S. Hasezawa
    Radiation Safety Management, 12(2), 43-47, doi:10.12950/rsm.12.43 (2013)
  30. 東京湾底質における福島第一原発事故由来の放射性セシウムの濃度変化
    添盛 晃久, 小豆川 勝見, 野川 憲夫, 桧垣 正吾, 松尾 基之
    分析化学 62(12), 1079-1086, doi:10.2116/bunsekikagaku.62.1079 (2013)
  31. Application of ICP-DRC-MS to screening test of strontium and plutonium in environmental samples at Fukushima
    M. Sakama, Y. Nagano, T. Saze, S. Higaki, T. Kitade, N. Izawa, O. Shikino and S. Nakayama
    Applied Radiation and Isotopes, 81, 201-207 doi:10.1016/j.apradiso.2013.03.056 (2013)
  32. Decontamination of radioactivity from contaminated vegetables derived from the Fukushima nuclear accident
    K. Shiba, Y. Kitamura, T. Kozaka, I. Uno, K. Shimizu, K. Masumoto, M. Hirota, S. Higaki, H.Miyoshi, T. Saze, M.Sakama, M. Yanaga
    Radiation Measurements 55, 26-29, doi:10.1016/j.radmeas.2013.01.010 (2013)
  33. The Reductive Effect of an Anti-Pollinosis Mask against Internal Exposure from Radioactive Materials Dispersed from the Fukushima Daiichi Nuclear Disaster
    S. Higaki* and M. Hirota
    Health Physics 104(2), 227-231, doi:10.1097/HP.0b013e318266ad51 (2013)
  34. Characteristics of radioactive contamination of vegetables derived from the Fukushima nuclear accident
    K. Shiba, Y. Kitamura, T. Kozaka, I. Uno, K. Shimizu, M. Hirota, S. Higaki and K. Masumoto
    Radiation Safety Management 11(1) , 19-22, doi:10.12950/rsm.11.19 (2012)
  35. Decontamination Efficiencies of Pot Type Water Purifiers for 131I, 134Cs and 137Cs in Rainwater Contaminated during Fukushima Daiichi Nuclear Disaster
    S. Higaki* and M. Hirota
    PLoS ONE 7(5), e37184, doi:10.1371/journal.pone.0037184 (2012)
  36. Radionuclide Analysis on Bamboos Following the Fukushima Nuclear Accident
    T. Higaki, S. Higaki, M. Hirota, K. Akita and S. Hasezawa
    PLoS ONE 7(4), e34766, doi:10.1371/journal.pone.0034766 (2012)
  37. 福島第一原子力発電所事故後の茨城県産牧草を給与した牛の乳における放射性核種濃度
    橋本 健, 田野井 慶太朗, 桜井 健太, 飯本 武志, 野川 憲夫, 桧垣 正吾, 小坂 尚樹, 高橋 友継, 榎本 百合子, 小野山 一郎, 李 俊佑, 眞鍋 昇, 中西 友子
    RADIOISOTOPES, 60(8), 335-338, doi:10.3769/radioisotopes.60.335 (2011)
  38. Emission of Methane from Stainless Steel Surface Investigated by Using Tritium as a Radioactive Tracer
    S. Higaki, Y. Oya, and Y. Makide
    Chemistry Letters, 35, 292-293, doi:10.1246/cl.2006.292 (2006)
  39. Extraction of Lanthanoids(III) as Thiocyanates with Trioctylphosphine Oxide into Aliphatic and Aromatic Solvents
    Y. Hasegawa, M. Hara, S. Higaki, and I. Matsubayashi
    Solvent Extraction Resarch and Development, Japan, 7, 152-158 (2000)