More than a century of radiation research has provided us with extensive information on health effects and biological mechanism caused by radiation exposure, especially for moderate to high dose radiation. This has contributed especially in determining the standard criteria of radiation protection.

At the same time, rapid increase in radiological procedures during the past century has made significant contribution to the human health. Nowadays, medical radiation has become a major source of human exposure to ionizing radiation. Such widespread use of ionizing radiation in medical practice alerts the medical community to carefully optimize the procedures considering the benefit and risk of each patient. However, the health effects have not been confirmed for low dose and low dose-rate of radiation exposure.

In 2018, we organized the International Workshop on the Biological Effects of Radiation-Bridging the Gap between Radiobiology and Medical Use of Ionizing Radiation (BER2018)(https://www.rcnp.osaka-u.ac.jp/~ber2018/index.html) in Osaka to overview updated concepts of biological effects of radiation, with particular focus on medical exposure. The participants agreed the need of integrative efforts of multidisciplinary fields to solve the problem and published the Osaka Call-for-Action (https://www.rcnp.osaka-u.ac.jp/~ber2018/index.html#theme).

In order to further discuss and advance the collaborative research, we started the 195 th Committee on Utilization and Biological Effects Radiation (http://radi.rirc.kyoto-u.ac.jp/c195/en/index.html) in 2019, under the University-Industry Research Cooperation program of Japan Society for the Promotion of Science(JSPS). The Committee has placed importance on scientific, evidence-based discussions in investigating the biological effects of radiation, and conducted the intensive discussion among the participants of various expertise. As medical use of radiation is expanding globally, the scientific research to clarify the biological effects of low-dose and low-dose-rate exposure is essential not only for optimization of the current procedures but also for future development of new technology. It is my pleasure to invite all participants for interdisciplinary discussion toward the next decade.