The CCRI News resource

A half-day Workshop on Metrology for Proton and Hadron Therapy Workshop was held at Minamisoma city, Fukushima prefecture, Japan, 16 September 2025. It was organized by the section I “dosimetry” of the Consultative Committee for Ionizing Radiation with the support of the Fukushima Institute for Research Education and Innovation (F-REI) and the National Metrology Institute of Japan (NMIJ). About 60 participants, 20 of them connected remotely, discussed the status and future developments in metrology for therapeutic applications of protons and light ions*.

Japan has a long history of proton/hadron therapy, and therefore the workshop opened with an overview of this modality over the last 40 years. Following this, attendees heard technical presentations on the state-of-the-art in metrology and descriptions of new activities related to reference dosimetry protocol development. Prior to a discussion on standards and comparisons, the theme returned to the clinical perspective to provide a clear statement of stakeholder needs in dosimetry.

A primary outcome from the discussions was that there is a need to initiate a comparison between NMIs/DIs having proton primary standards already established, as well as a desire for guidelines and support for the members of CCRI(I) that do not currently have such a capacity but have a future requirement to meet the dosimetry needs of national proton therapy programs.

This “workshop” was followed by a meeting of the Section I “dosimetry” of the Consultative Committee for Ionizing Radiation, where these needs were discussed and led to the proposal of a creation of a CCRI(I) task group to rapidly create a comparison program in proton therapy, and a working group focused on the development of metrology for emerging therapy modalities.

* the term “light ions” refers to ions with atomic number in the range 2-8