The CCRI News resource

The 2025 meeting of Section I “Dosimetry” of the Consultative Committee for Ionizing Radiation took place in Minamisoma City, Fukushima Prefecture, Japan, from 17 to 18 September 2025, with the support of the Fukushima Institute for Research Education and Innovation (F-REI) and the National Metrology Institute of Japan (NMIJ). Around 50 participants, including 10 who joined remotely, gathered over two days to review the status of dosimetry and to consider future developments.

In addition to presentations on completed, ongoing, and planned comparison exercises, the program dedicated significant time to technical discussions on dosimetry in diagnostic radiology, Monte Carlo simulations in dosimetry, and challenges in radiation processing. These exchanges, together with the outcomes of the two previous workshops, were brought forward for revision of the strategy plans of CCRI(I) and the BIPM.

The committee adopted a series of resolutions that reflect both technical and organizational priorities. It endorsed the recommendations from the Brachytherapy Workshop held on September 15 and proposed the establishment of a task group to prepare a protocol for a proton dosimetry comparison to be ideally undertaken within the next two years. A new Working Group was also proposed to accelerate the development of proton primary standards across the RMOs, to investigate the challenges posed by carbon ion dosimetry, and to extend metrology into other emerging treatment modalities. Another task group was proposed to provide guidance on traceability and uncertainty estimation in the use of Monte Carlo radiation transport systems applied to dosimetry standards. It was suggested that the KCWG(I) would benefit from new members and an updated terms of reference, while the committee also resolved to appoint a new representative to the CCRI RTQI Working Group.

Requests were made to other subcommittees in support of these goals. The CCRI COM WG was asked to explore ways of enhancing the visibility and impact of reports submitted by delegates and liaisons, without compromising the depth of information currently provided. The KCWG(I) was invited to consider the treatment of CMCs that exceed the 15-year comparison period under extraordinary circumstances beyond a laboratory’s control, and to review existing physical and normative standards to determine whether current Key Comparisons can accommodate additional beam qualities, such as the ISO4037 N-series for radiation protection.

With respect to the BIPM strategy, the CCRI(I) concluded that there is no pressing need at for the BIPM to develop a high-energy electron standard but has a role to play in defining the KCRV for a future comparison. It emphasized, however, the critical importance of maintaining a therapy-level Co-60 source at the BIPM to support both comparisons and calibrations.

Finally, the committee welcomed two new members, OAP (Thailand) and FANR (UAE), whose presentations further underlined the vitality, diversity, and richness of the CCRI(I) community.