Annual Report 2023
Central Radioisotope Division
Masamichi Ishiai, Akihiro Yanagihara, Hiroshi Tanooka, Hirofumi Fujii, Mitsuko Masutani, Makoto Ihara, Syoji Imamichi, Ying Tong, Takahiro Hamoya, Gen Fujii, Rikiya Imamura, Yui Kanai, Airi Nakano, Hideyuki Watanuma
Introduction
The Central Radioisotope Division is a joint usage facility composed of the Research Support Core of the Fundamental Innovative Oncology Core (FIOC) of the National Cancer Center (NCC) Research Institute. We provide advanced technical training and education for researchers in the NCC. We also support and advise on radiation-related cancer research.
The Team and What We Do
Our division manages radioisotope (RI) materials, gamma-ray irradiators (Gammacell 220 with Co-60 souce and Gammacell 40 Exactor with Cs-137 source), and radiation-related equipment to promote advanced cancer research in a smooth manner. Our division also conducts radiation management studies so that researchers can use RI resources safely and effectively.
Research Activities
We have been conducting research on cancer risk after irradiation by several approaches. First, we have focused on the study of molecular mechanisms of cellular responses such as DNA damage signaling, and DNA repair pathways after DNA damage, including by irradiation. Second, we have developed a radiotherapy model by mouse. Third, through collaboration with the Department of Radiation Oncology an NCC Hospital and industry, we conducted preclinical research as well as basic and translational studies of the biological effects by accelerator-based neutron irradiation, and boron neutron capture therapy (BNCT) system introduced in the NCC. Fourth, we have conducted basic research on alpha-emitting nuclides for biological/medical use. Fifth, we have also investigated the molecular mechanisms of cancer chemoprevention. The research topics were presented at international and domestic conferences and published as treatises.
Facility Utilization Information
The usage frequency of gamma-ray irradiators and used amounts of RI for the past five years are shown in Tables 1 and 2, respectively.
Table 1. Number of times gamma-ray irradiators were used 
Table 2. Used amounts of radioisotopes (MBq) 
Education
We provide an annual course of education and training in radiation biology, handling of RI, and operating of gamma-ray irradiators.
Three graduate students were trained in our division, and one received a Ph.D. degree and the others received master’s degrees.
Future Prospects
A clinical trial for cancer patients using BNCT has been initiated in the NCC Hospital, so opportunities to handle neutron-irradiated cells have increased in our division. In addition, we have started basic research on radionuclide therapy using alpha-ray emitting nuclide.
List of papers published in 2023
Journal
1. Nakamura S, Imamichi S, Shimada K, Takemori M, Kanai Y, Iijima K, Chiba T, Nakayama H, Nakaichi T, Mikasa S, Urago Y, Kashihara T, Takahashi K, Nishio T, Okamoto H, Itami J, Ishiai M, Suzuki M, Igaki H, Masutani M. Relative biological effectiveness for epithermal neutron beam contaminated with fast neutrons in the linear accelerator-based boron neutron capture therapy system coupled to a solid-state lithium target. Journal of radiation research, 64:661-667, 2023
2. Kondo N, Masutani M, Imamichi S, Matsumoto Y, Nakai K. Strategies for Preclinical Studies Evaluating the Biological Effects of an Accelerator-Based Boron Neutron Capture Therapy System. Cancer biotherapy & radiopharmaceuticals, 38:173-183, 2023
3. Perico D, Di Silvestre D, Imamichi S, Sanada Y, Masutani M, Mauri PL. Systems Biology Approach to Investigate Biomarkers, Boron-10 Carriers, and Mechanisms Useful for Improving Boron Neutron Capture Therapy. Cancer biotherapy & radiopharmaceuticals, 38:152-159, 2023
4. Imamura R, Saito M, Shimada M, Kobayashi J, Ishiai M, Matsumoto Y. APTX acts in DNA double-strand break repair in a manner distinct from XRCC4. Journal of radiation research, 64:485-495, 2023
5. Perico D, Tong Y, Chen L, Imamichi S, Sanada Y, Ishiai M, Suzuki M, Masutani M, Mauri P. Proteomic Characterization of SAS Cell-Derived Extracellular Vesicles in Relation to Both BPA and Neutron Irradiation Doses. Cells, 12:1562, 2023