It is my privilege and great pleasure to invite you to the 31st Annual Meeting of Japanese Society for Radiation Oncology (JASTRO) that will take place on October 11-13, 2018 at the Kyoto International Conference Center.

The theme of the 31st annual meeting of JASTRO is “best time, best space”, which is the fundamentals of radiation therapy (RT). By improving the spatial dose distribution, clinical results of RT were improved and indications of RT were widened. It is well known that overall treatment time or timing of RT and combined therapy has big impacts on the effects of RT. Significant anatomic changes, including shrinking of the primary tumor or nodal masses and body weight loss, can occur during fractionated RT. Image-guided RT and adaptive RT are now clinically applicable, which can correct such daily or weekly tumor and normal tissue variations. Also, in this annual meeting, we have ESTRO/JASTRO Joint Symposium on time factor in RT. Thus, I hope we could discuss the recent advance of RT based on the time and space factors.

In Japanese societies for the tea ceremony, arts, and martial arts, there is a word of “Shu-ha-ri”. This word is the subtheme of this meeting. Shu is the level of imitation of a master. Ha is breakthrough from the lesson of the master. Ri is innovation to establish a new style of their own. In the 31st annual meeting, we want to discuss various aspects of RT from the level of imitation to innovation under the idea of “Shu-ha-ri”.

October in Kyoto is the best season for sightseeing. I believe this annual meeting will be successful, and strengthen the mutual understanding and friendship of JASTRO members and international colleagues.