Metrology, Standards, and Mission: Synopsis of the 2026 Annual Meeting of the Council on Ionizing Radiation Measurements and Standards (CIRMS)

Abstract

The Council on Ionizing Radiation Measurements and Standards (CIRMS) is an independent, non-profit council composed of experts from academia, government, and industry across all areas of ionizing radiation science and technology, providing leadership, focus, and coordinated action on emerging radiation metrology needs. This mission is achieved through the organization of an annual scientific conference and the periodic publication of a Needs Report which identifies priority areas in ionizing radiation measurements and standards. This article summarizes the outcomes from the CIRMS 2026 meeting which was held 13–15 April 2026 at The Universities at Shady Grove in Rockville, Maryland, United States. Participants represented a broad cross-section of the radiation science community, including radiation metrologists, academic researchers, government scientists, and industry stakeholders. The meeting featured plenary presentations, topical breakouts, and poster sessions. The breakout sessions were organized by the three subcommittees of the CIRMS Science and Technology Committee: Medical Applications, Radiation Protection and Homeland Security, and Radiation Processing and Material Effects. Topics covered during the meeting included cobalt-60 (⁶⁰Co) and cesium-137 (¹³⁷Cs) production, medical device sterilization, FLASH radiotherapy dosimetry, neutron dosimetry, radiation standards for next-generation fusion power systems, Monte Carlo modeling, and other topics relevant to radiation measurements and standards. The CIRMS 2026 meeting highlighted challenges that must be addressed to advance ionizing radiation science and technology and provided important input for the next Needs Report.

1. INTRODUCTION

The mission of the Council on Ionizing Radiation Measurements and Standards (CIRMS), formed in 1992, is to bring together stakeholders to advance measurement capabilities and standards to support the safe and effective use of ionizing radiation for societal benefit (Koch 2006). CIRMS is an independent, non-profit council composed of experts from academia, government, and industry across all areas of ionizing radiation science and technology, providing leadership, focus, and coordinated action on emerging radiation metrology needs. This mission is achieved through the organization of an annual scientific conference and the periodic publication of a Needs Report (CIRMS 1994; CIRMS 1998; CIRMS 2001; CIRMS 2004; CIRMS 2011) which identifies priority areas in ionizing radiation measurements and standards. Developed through expert consensus, the Needs Report serves as a resource for guiding program development and research investment, particularly when resources are constrained. This article summarizes the proceedings of the 32^nd annual CIRMS meeting (CIRMS 2026).

2. CIRMS 2026 MEETING

A total of 114 people attended the CIRMS 2026 meeting, which was held 13–15 April 2026 in Rockville, Maryland, United States at The Universities at Shady Grove (Fig. 1). Unlike meetings organized around single disciplines, CIRMS intentionally brings together stakeholders from all areas of ionizing radiation science, including medicine, radiation processing, material science, radiation protection, homeland security, and radiation metrology. Participants in the CIRMS 2026 meeting represented a broad cross-section of the scientific community, including radiation metrologists, academic researchers, government scientists, and industry stakeholders. Most participants were from the United States, with additional participation from Canada and the United Kingdom. Participants represented approximately 22 universities, 10 government agencies, and 13 radiation technology companies. Approximately 25% of attendees were from the Radiation Physics Division of the National Institute of Standards and Technology (NIST), whose expertise in radiation metrology and standards has been central to many CIRMS activities and initiatives since its inception.

Fig. 1.

Group photograph of participants at the CIRMS 2026 meeting held at The Universities at Shady Grove in Rockville, Maryland, United States. The photograph was captured using an aerial drone. The authors have confirmed that any identifiable individuals have given their consent for publication.

The theme of the CIRMS 2026 meeting was “Embracing Our Purpose: Anticipating Radiation Measurement Needs,” reflecting a deliberate effort by CIRMS to reinvigorate the development of its Needs Report. The program consisted of 2.5 days of lectures and poster sessions highlighting advances in radiation metrology, as well as emerging technologies and research areas requiring new standards or measurement support. Participants gathered each morning for plenary sessions featuring speakers on topics of broad interest, while the afternoons were devoted to more focused topical breakout sessions with dedicated time for discussion of the Needs Report. The breakout sessions were organized by the three subcommittees of the CIRMS Science and Technology Committee: Medical Applications, Radiation Protection and Homeland Security, and Radiation Processing and Material Effects. The scientific program was created through a combination of invited speakers and submitted abstracts. Consistent with the CIRMS mission, all speakers were asked to highlight specific needs related to radiation measurements or standards in their presentations. The full meeting program can be found in the Supplementary Material.

2.1. Plenaries

2.1.1. Keynote: Perspective from the Hill

Ariel Marshall (Scale AI) presented an overview of the current funding and workforce challenges facing federal science agencies and explained how decisions on Capitol Hill are shaped by competing priorities and constrained resources. She emphasized that effective advocacy requires translating technical work into clear, relevant, and actionable messaging that aligns with policymakers’ economic, health, and national priorities. Following her talk, participants discussed how CIRMS can more effectively communicate the consequences of underinvestment in radiation metrology infrastructure. This presentation emphasized that sustained funding is essential for maintaining national capabilities in ionizing radiation measurements and standards.

2.1.2. Plenary: Cobalt-60 and gamma applications—Effective, understood, growing, and sustainable

Richard Wiens (Nordion) presented an overview of cobalt-60 production and gamma irradiation technologies, with an emphasis on medical sterilization, cancer treatment, and the global supply chain. His presentation highlighted that approximately 30% of single-use medical devices worldwide are sterilized by cobalt-60 gamma irradiation and that more than 80,000 cancer patients annually receive treatment using the Gamma Knife (Hafez et al. 2020) or GammaPod technologies (Yu et al. 2013). To meet the growing demand for cobalt-60, new initiatives are underway to expand production capacity. Production of cobalt-60 involves irradiating high-purity cobalt-59 targets inside nuclear reactors for 18–60 months. Examples of new production initiatives include the conversion of multiple CANDU reactor units at the Darlington Nuclear Generating Station (Bowmanville, Ontario, Canada) to enable cobalt-60 production during normal power generation operations, with first production expected around 2028, as well as the development of pressurized water reactor technology in the United States, with delivery expected by approximately 2030. Besides sterilization and radiotherapy, cobalt-60 is also important for radiation metrology because it provides a stable, well-characterized source of gamma radiation that has served as the foundation for the calibration of many radiation detection instruments for decades. This presentation underscored the need for coordinated international efforts to ensure a resilient cobalt-60 supply (Chou et al. 2018).

2.1.3. Plenary: Heat you can measure—Verification and standards for clinical hyperthermia

Dario Rodrigues (University of Maryland School of Medicine) presented on clinical hyperthermia, a technique in which radiofrequency electromagnetic fields are used to heat tissues in cancer patients undergoing radiotherapy. By elevating tumor temperatures to a therapeutic range, the technique can increase tumor sensitivity to radiation. Although clinical hyperthermia can improve treatment efficacy (Scott et al. 1983), widespread implementation is limited because the therapy lacks standardized dosimetry, calibration, and quality-assurance frameworks (Paulides et al. 2021). A central challenge is that the electric fields, specific absorption rate (SAR), and temperature rise inside the patient are difficult to measure directly (Lang et al. 2025; Gavazzi et al. 2020). Wider clinical implementation will require traceable calibration approaches, patient-specific treatment planning, and standardized phantoms for quality assurance.

2.1.4. Keynote: Fusion industry needs

Andrea Saltos (Commonwealth Fusion Systems) presented the status of the rapidly expanding fusion energy industry and described the radiation measurement challenges associated with deploying next-generation fusion power systems. She described Commonwealth Fusion Systems’ pathway from the SPARC (Creely et al. 2020) demonstration tokamak to ARC, its planned commercial fusion power plant (Sorbom et al. 2015; Kuang et al. 2018). Fusion reactor environments create unique radiation protection and metrology challenges due to the broad neutron spectrum (thermal to 14 MeV), mixed neutron and photon radiation fields, strong spatial gradients, pulsed operation, and intense magnetic fields. She stressed that the performance of existing detectors and dosimeters has not been sufficiently tested under fusion conditions (Angelone and Raj 2022). She also described the need for standardized calibration methods and traceable neutron reference fields with spectra representative of deuterium–tritium fusion systems rather than traditional neutron sources such as californium-252 or americium–beryllium (AmBe). Also needed are strategies to minimize the uncertainty in fusion power calculations. Increased coordination between the fusion industry and standards laboratories is needed to support the safe deployment and operation of future fusion reactors.

2.1.5. Plenary: Investigating the FLASH effect with Monte Carlo simulations

Jan Schuemann (Massachusetts General Hospital and Harvard Medical School) discussed the capabilities of the TOPAS-nBio (Schuemann et al. 2019) Monte Carlo tool for investigating the underlying mechanisms of the FLASH effect in radiotherapy, the preferential sparing of healthy tissue observed in a number of ultra-high dose rate (UHDR) irradiation studies (Favaudon et al. 2014; Borghini et al. 2024). The presentation centered around the modeling of processes occurring over extremely short time scales after irradiation (milliseconds). Experimental investigations are inherently limited by temporal resolution, whereas track-structure Monte Carlo radiation transport simulations can integrate radiation transport, radiochemistry, physics, and biology to help fill this gap (Masilela et al. 2026). Although validation remains challenging, these models provide valuable insight into the relative effect of various parameters (e.g. dose rate, oxygen depletion, radical chemistry) for testing competing hypotheses of the underlying mechanisms of the FLASH effect (Yan et al. 2024). High-quality benchmark data integrating physical, chemical, and biological measurements are needed for model validation.

2.1.6. Plenary: Innovative dosimetry and safe nuclear waste management—Building trust through science and precision

Robert Hayes (North Carolina State University) presented several unique dosimetry techniques to evaluate contamination from nuclear waste sites. He discussed advancements in nuclear waste management and radiation dosimetry, emphasizing how precision measurements can enhance safety, non-proliferation safeguards, and public confidence. For example, he highlighted how techniques such as electron paramagnetic resonance, optically stimulated luminescence (OSL), and solid-state dosimetry using ubiquitous building materials and commercial surface mount resistors are changing the ability to assess radiation exposure and material integrity in waste storage environments (Hayes and Sholom 2017). These methods can yield depth–dose profiles capable of discriminating historical possession of Highly Enriched Uranium (HEU) versus Low Enriched Uranium (LEU). He also described methods for performing retrospective dose reconstructions following events such as the 2014 Waste Isolation Pilot Plant (WIPP) release or other nuclear accidents by using the TL response of quartz in bricks (O’Mara and Hayes 2018). Finally, he provided a comprehensive contextualization of radiation risk, comparing natural background and medical exposures to thresholds for acute effects. Traceable retrospective dosimetry methods and validated environmental measurement techniques are essential not only for radiation protection, but for building public trust and regulatory confidence in nuclear technologies.

2.1.7. Keynote: Scientific exchange on modeling and simulation for radiation sterilization

John Logar (Johnson & Johnson) summarized the outcomes of the CIRMS Scientific Exchange on Modeling and Simulation for Radiation Sterilization, held at NIST in Gaithersburg, Maryland on 16–17 September 2025. The meeting brought together 47 participants from 30 organizations to address how computational simulation can complement, and in some cases reduce reliance on, physical dosimetry in radiation sterilization processes. The core problem identified was that radiation sterilization depends heavily on physical dosimetry, limiting supply chain agility and device innovation as products requiring sterilization become increasingly complex. The industry lacks the standards, validation methods, and regulatory pathways needed for trusted simulation-based qualifications. Experts from the medical physics community were specifically invited to the scientific exchange to share lessons learned from the successful integration of simulation-based treatment planning in radiation oncology. A key outcome of the exchange was the identification of several priority areas: (1) the formation of a working group to develop a specific open-source use case (e.g. a standardized syringe geometry); (2) the fabrication of standard reference phantoms (homogeneous, layered, and semi-realistic pallet configurations); (3) creation of a proficiency testing program; (4) systematic effort to translate relevant medical physics standards and guidance into industrial sterilization applications. This scientific exchange exemplified how CIRMS can help build bridges across sectors to address radiation metrology challenges.

2.1.8. Special session in honor of Miral Dizdaroglu: Advancing measurements of DNA damage and biodosimetry

On the final day of the conference (15 April 2026), a special session was held in honor of the late Miral Dizdaroglu, whose pioneering work established a measurement-centered approach to understanding radiation-induced DNA damage. Dizdaroglu’s research provided rigorous methods for chemical identification and quantification of oxidative DNA lesions, helping shift the field beyond broad physical dose descriptors toward molecularly specific measures of biological damage (Desrosiers et al. 2013).

The session opened with Amitava Adhikary (University of Iowa) who described collaborative work with Miral Dizdaroglu and colleagues which integrated experimental and computational methods to study hydroxyl radical-mediated and high linear energy transfer (LET) track-structure DNA damage. A key finding was that DNA lesions increase with LET and become especially important near the Bragg peak, where dense ionization tracks create clustered damage that is more difficult to repair (Halliwell et al. 2021; Sevilla et al. 2016).

Steven Swarts (University of Florida) then highlighted Dizdaroglu’s transformative use of gas chromatography-mass spectrometry and related analytical methods to quantify multiple DNA and chromatin modifications simultaneously (Dizdaroglu 1984). That capability gave the field a much stronger mechanistic basis for distinguishing oxidative, reductive, direct, and quasi-direct pathways of radiation damage, and helped establish lesion-resolved measurement as a realistic metrological target rather than a purely biological endpoint (Dizdaroglu and Jaruga 2012).

Next, Joseph Robertson (NIST) presented a conceptual proposal for a new unit, the “dizdar” (DZ), defined as the number of DNA lesions per kilogram. The conceptual unit, named in honor of Miral Dizdaroglu, would complement the absorbed dose measured in gray (Gy) by directly quantifying biologically relevant molecular damage. The proposal included the development of a novel measurement approach using nanopore resistive pulse sensing to rapidly quantify DNA damage and its time-dependent repair (Lamontagne et al. 2025).

The final speaker in the special session was David Bolduc (Armed Forces Radiobiology Research Institute (AFRRI)), who presented the development of rapid, blood-based triage models for assessing radiation injury following nuclear or radiological emergencies. The work used archived hematology datasets on baboons exposed to gamma and mixed gamma–neutron radiation (Hérodin et al. 2014; Valente et al. 2015) to train artificial intelligence models capable of predicting radiation dose (0–8 Gy) and the severity of hematopoietic acute radiation syndrome (HARS) according to the Medical Treatment Protocols for Radiation Accident Victims (METREPOL) triage classification system (Gorin et al. 2006). The findings support the use of standard blood cell count analysis as a practical tool for radiation triage.

A common theme of the presentations in this session was that absorbed dose (Gy) and equivalent dose (Sv) are not sufficient to characterize the biological effects of radiation, and that direct quantification of DNA damage and other biological endpoints is increasingly important for advancing applications in medicine, radiation protection, and emergency response.

2.1.9. Capstone: What is CIRMS for?

Malcolm McEwen (National Research Council Canada) gave an insightful presentation on the importance of the CIRMS mission and its unique role as a forum for stakeholders from all areas of ionizing radiation science and technology to interact directly. Malcolm explained how the activities of CIRMS align closely with the Consultative Committee for Ionizing Radiation (CCRI). However, while CCRI participation is largely limited to national metrology institutes and a relatively small number of stakeholder organizations, CIRMS has a much wider reach, extending the relevance and impact of radiation metrology activities. He reiterated the value of the Needs Report and encouraged CIRMS to further embrace its growing international role within the radiation measurements and standards community. This presentation reinforced the importance of CIRMS for facilitating international and cross-sector radiation metrology coordination.

3. TOPICAL BREAKOUT SESSIONS

The breakout sessions held on Monday and Tuesday afternoons focused on radiation measurement and standards needs in specific topic areas. The resulting findings and recommendations are summarized below and in Tables 1, 2, 3.

Table 1.

Discussion topics and needs identified during the Monday breakout session 1.

Medical Applications Subcommittee	Joint Session: Radiation Protection and Homeland Security & Radiation Processing and Material Effects Subcommittees
Session Theme: Neutron Dosimetry	Session Theme: Radiation Processing Applications
Chairs: Sergio Morató Rafet, Thomas Winters, and Matthew Mille	Chair: Ileana Pazos
• Sustained and modernized neutron standards and calibration infrastructure, including mixed-field dosimetry capability	• Standards and regulatory guidance on the use of mathematical modeling in the context of radiation processing
• Improved measurement methods and standards for characterizing neutron energy spectra spanning from thermal energies to 250 MeV	• Internationally harmonized standards and regulatory frameworks governing the trade of medical devices, food, and other irradiated products
• Expanded radiobiological datasets for quantifying neutron relative biological effectiveness (RBE) as a function of energy, dose, and dose rate	• Robust data on the effects of irradiating various produce commodities to support product-specific, science-based dose limits
• Updated neutron therapy protocols and reference standards incorporating modern Monte Carlo-based methods and patient-specific quality assurance	• Balanced scientific evaluation of the safety, benefits, and limitations of food irradiation to increase public acceptance, inform regulatory decision-making, and encourage private-sector investment
• Improved integration of neutron biological effects into patient treatment planning and emergency response consequence management

Table 2.

Discussion topics and needs identified during the Monday breakout session 2.

Joint Session: Medical Applications Subcommittee & Radiation Processing and Material Effects Subcommittees	Radiation Protection and Homeland Security Subcommittee
Session Theme: FLASH Radiotherapy Dosimetry	Session Theme: Radiation Measurement & Consequence Management
Chairs: Spencer Mickum, Matthew Mille, Wesley Culberson	Chairs: Emmanuel Mate-Kole and Sara Dumit
• Standardized dosimetry protocols for UHDR radiotherapy	• Standardized tools for integrating physical measurements, bioassay data, and medical-treatment information to perform internal dose assessment following radionuclide intake
• Improved characterization of detector response under UHDR conditions
• Advanced UHDR beam monitoring, delivery verification, and quality assurance tools	• Standardized tools for performing neutron activation analysis
• Primary standards and dedicated UHDR beamlines at primary standards laboratories	• Development and validation of mixed-field medical countermeasures to improve preparedness for radiological and nuclear incidents
• Sustained support for standards laboratories, interlaboratory comparisons, and independent detector testing	• Improved methods for relating physical dose measurements to biological effects and medical outcomes for consequence management

Table 3.

Discussion topics and needs identified during the Tuesday afternoon breakout session 3.

Joint Session: Medical Applications & Radiation Protection and Homeland Security Subcommittees	Radiation Processing and Material Effects Subcommittee
Session Theme: OSL Dosimetry Alternatives	Session Theme: Radiation Modality Comparisons
Chair: Wesley Culberson	Chair: Spencer Mickum
• Accurate, clinically practical, and cost-effective dosimeters for in vivo radiotherapy dose verification	• Improved dosimeters for low-energy (<1 MeV) electron beam and for low doses (<1 kGy) of electron beam and X-ray radiation
• Wireless or minimally obtrusive detector designs to improve clinical usability and workflow integration	• Training and standardized protocols to support wider implementation of machine-based radiation technologies
• Dosimetry systems that are compatible with clinical imaging, treatment delivery, and data management workflows	• Validation of alternatives to cobalt-60 and cesium-137 for radiation instrument calibration to support security-driven source reduction policies without compromising measurement traceability
• Expanded availability of OSL reader technologies and sustained support for OSL-based dosimetry systems	• Scalable dosimetry methods for rapid dose assessment and triage following radiological or nuclear incidents
• Independent evaluation of detectors before clinical implementation

3.1. Monday afternoon breakout session 1

3.1.1. Neutron dosimetry

This breakout session focused on emerging challenges and advances in neutron dosimetry and biological effect estimation (Fig. 2). The session started with Yannick Poirier (University of Maryland School of Medicine) who gave a presentation addressing radiation protection considerations for secondary neutrons and neutron activation in FLASH radiotherapy facilities, emphasizing the need to carefully evaluate shielding and safety assumptions for UHDR electron and proton systems (Poirier et al. 2021). Increased bremsstrahlung production, neutron generation, and activation of shielding and beamline components should be considered.

Fig. 2.

Photograph of the Monday medical subcommittee afternoon breakout sessions at the CIRMS 2026 meeting. The authors have confirmed that any identifiable participants have given their consent for publication.

Next, Daniela Stricklin (Centers for Disease Control and Prevention) described uncertainty in the relative biological effectiveness (RBE) of neutrons and its impact on dose reconstruction following nuclear detonation and criticality scenarios (Stricklin et al. 2021). A major gap is the difficulty translating animal data into assessments of human health risk.

Daniel Jardin (NIST) reviewed ongoing efforts at NIST to maintain and modernize national neutron calibration capabilities, including neutron source standards, personnel protection instrument calibration, and high-dose neutron irradiation facilities.

Finally, Adrienne Lehnert (University of Washington) presented on the topic of intensity modulated neutron therapy (IMNT) which is used to treat cancers resistant to X-rays or protons (Lehnert et al. 2025). She described the implementation of Monte Carlo-based treatment planning and patient-specific quality assurance methods, but that updated dosimetry standards are needed because protocols are still largely based on AAPM Report 7 (American Association of Physicists in Medicine 1980), published in 1980.

A common theme from this session was the need for improved data on the RBE of neutrons. Because neutron RBE varies with energy, metrology efforts should prioritize improving capability to measure neutron energy spectra ranging from thermal energies up to approximately 250 MeV, the maximum energy encountered in proton therapy applications.

3.1.2. Radiation processing applications

This session covered applications of radiation processing in the sterilization of single-use medical devices and for the treatment of fresh produce.

Tobias Funk (Dose Insight and Triple Ring Technologies) presented a study of radiation sterilization of blood lancets that examined how packaging configurations affect the dose uniformity ratio (DUR), defined as the maximum dose received by the product divided by the minimum dose. Experimental measurements and virtual dose mapping simulations showed that the DUR for a randomly packed box of lancets can be as high as 1.6. Ayeh Jowzaee (STERIS Applied Sterilization Technologies) presented similar work on irradiation of plastic syringes and found that DUR varies with the orientation of electron beam irradiation, with a more uniform dose being delivered when a box of syringes is irradiated from the front (DUR 1.5) versus from the side or the long axis direction (DUR 1.7 and 1.9, respectively). In both studies, virtual dose mapping simulations closely agreed with experimental measurements and provided estimates of the dose distribution throughout the product package, beyond the limited number of positions which could be measured experimentally. These results demonstrate the value of modeling for sterilization process development and validation.

Emilia Bustos (J. B. TRINI Associates) provided an overview of the use of phytosanitary irradiation in the international trade of fresh fruits and vegetables (Bustos-Griffin et al. 2015). The phytosanitary irradiation industry is growing, with Mexico being the largest user of the technology for the treatment of guavas and other fruits. Although international standards have helped facilitate adoption, the technology remains underutilized compared to other treatment options.

Michael Christofaro (Reveam) described Reveam’s electronic cold pasteurization (ECP) technology (Nambeesan et al. 2018) and the development of a new treatment center in Miami, Florida. ECP can extend the shelf life of fresh berries and other produce without degrading product quality. One challenge is dose variability due to product packaging and arrangement during treatment. Christofaro noted that the current generalized maximum dose limit of 1 kGy is restrictive and suggested that dose limits should be supported with technical justification based on measured data for specific products and applications. He cited research showing that higher doses can provide enhanced pathogen control and shelf-life extension for some products (Nunes et al. 2008; Lung et al. 2015).

Together, these presentations highlighted the importance of dosimetry, modeling, and product-specific evidence for informing regulations, increasing public acceptance, and encouraging private investment in radiation processing technologies.

3.2. Monday afternoon breakout session 2

3.2.1. FLASH radiotherapy dosimetry

This session covered several emerging solutions for accurate dosimetry and quality assurance in the context of UHDR radiotherapy. The session started with Shannon Holmes (Standard Imaging) who presented the development of the Exradin A30, an ultra-thin parallel plate ionization chamber designed for use in FLASH radiotherapy settings. The design of this chamber features a 0.3 mm plate separation which creates a strong, uniform electric field to minimize ion recombination and saturation effects in UHDR beams while maintaining compatibility with existing calibration standards (Liu et al. 2024).

Malcolm McEwen (National Research Council Canada) then presented on a complementary multidetector system for traceability in UHDR beams. He described using two different portable calorimeters (graphite and aluminum) to provide redundancy in real-time measurements, radiochromic film, and alanine pellets which have direct traceability to national standards. This complementary dosimetry system enabled accurate measurement of absorbed dose in UHDR electron beams with a combined standard uncertainty of ~1.5%.

Lastly, Shuang Zhou (TetraImaging) described a multilayer strip ionization chamber (MLSIC) to measure dose and dose-rate distribution in three dimensions for proton FLASH radiotherapy beams (Zhou et al. 2025).

Together, the talks in this session demonstrated how measurement standards and innovations in radiation detector science are helping to characterize UHDR beams to support the safe clinical implementation of FLASH radiotherapy.

3.2.2. Radiation measurement and consequence management

This session covered a range of radiation measurement topics with applications in radiation protection and emergency response. Sara Dumit (Los Alamos National Laboratory) gave a presentation on the use of advanced biokinetic modeling methods to estimate the activity of plutonium intake and committed whole-body effective dose for a former nuclear worker. Her presentation showed that using early- and long-term bioassay measurements in conjunction with the chelation therapy information is important to accurately model radionuclide uptake and removal from the body.

Rui Fang (University of Nevada, Las Vegas) then presented on the development of an online Nuclear Activation Analysis System (NAAS), a web-based platform which automates spectral analysis and uses integrated radionuclide and nuclear reaction data to compute elemental concentrations, induced activities, and associated uncertainties.

Venkateshwara Dronamraju (Henry M. Jackson Foundation and AFRRI) presented results from a study in which mice were treated with BBT-059, a candidate radioprotective agent, prior to irradiation with either gamma rays or mixed gamma–neutron radiation fields. This work spoke to the need to develop and validate nuclear countermeasures for mitigating HARS.

Finally, Chris Passmore (Radiation Detection Company) described many common misconceptions in the field of personnel dosimetry and emphasized the importance of critically evaluating any performance claims and selecting appropriate dosimetry systems for the operational context.

This session illustrated the diversity of radiation measurement methods and standards needed to support the fields of radiation protection and emergency response.

3.3. Tuesday afternoon breakout session 3

3.3.1. OSL dosimetry alternatives

In 2024, the microSTARii medical dosimetry system (Landauer, Glenwood, IL) was permanently discontinued, including the nanoDot OSL dosimeters which were widely used by radiotherapy clinics for patient dose verification and quality assurance. The purpose of this session was to review experience with several alternative dosimetry technologies.

Yushi Chang (University of Maryland School of Medicine) started the session by describing the clinical implementation of metal-oxide-semiconductor field-effect transistor (MOSFET) detectors, highlighting advantages including portability, real-time readout, and acceptable clinical accuracy. Limitations include the need for individual dosimeter calibration, appropriate sensitivity-mode selection at low doses, and energy-dependent correction for the over-response of MOSFET detectors to kV imaging exposures. The wired cable setup also brings a practical challenge which may not be suitable for some applications.

Cliff Hammer (University of Wisconsin–Madison) then reviewed his experience with thermoluminescent dosimeters (TLDs), emphasizing their tissue-equivalence and suitability across a wide dose range. Drawbacks include the individual sensitivity of each TLD, delayed readout (24 hours), supralinear response with increasing dose, and over-response at kV versus MV energies (White et al. 2025).

Lastly, Louis Archambault (Université Laval) described the clinical implementation of plastic scintillation detectors (PSDs) which have the advantage of water equivalence, linear dose–response, energy independence, and real-time readout; however, relevant disadvantages are a small temperature dependence and the presence of an optical cable (Archambault et al. 2005).

An important conclusion from this session is that robust radiation metrology in the clinic should not rely on a single dosimeter technology. Instead, clinics may require complementary dosimetry systems with different strengths and limitations.

3.3.2. Radiation modality comparisons

This session focused on the challenges of implementation of alternative radiation technologies and measurement approaches to support industrial and emergency-response applications.

Leonard Fifield (Pacific Northwest National Laboratory) presented on recent efforts by Team Nablo, an international collaboration working to address measurement and training gaps impeding the adoption of X-ray and electron-beam technologies as alternatives to cobalt-60 irradiation and ethylene oxide sterilization. The team has conducted comparative studies of the modalities for various products such as medical device polymers and blood collection devices, finding that the effects depend on the material (Fifield et al. 2021a and 2021b; Krieguer et al. 2024). The team is also developing simulation tools such as the PENELOPE User-Friendly Fast Interface (PUFFIn) Monte Carlo interface (Schwarz et al. 2024) to improve access to dose-distribution modeling. Ongoing work aims to improve dosimetry for low-energy electron beam dosimetry (<1 MeV) and low-dose electron beam and X-ray radiation (<1 kGy). Training and standardized protocols are also needed to support wider implementation of machine-based radiation technologies.

Joshua Nuzzi (IBA Industrial Solutions) presented results of a Monte Carlo study comparing high-power X-ray and cobalt-60 gamma irradiators for sterilization processing, evaluating the DUR and throughput for pallets of products of varying density. The study found that a 7.3 MeV, 80 mA X-ray system achieved both lower DUR values and higher throughput than a 5 MCi cobalt-60 irradiator across all product densities considered, highlighting the potential of X-ray technology as a competitive alternative to gamma irradiation. Additional publicly available performance data for X-ray systems could help increase acceptance and adoption.

Zach Hope (Hopewell Designs) described the growing challenges associated with maintaining cesium-137 sources used for calibration of radiation instruments, noting that security-driven source reduction policies (National Academies of Sciences, Engineering, and Medicine 2021; National Research Council 2008) and declining demand have largely ended the production of high-activity cesium-137 sources. Users requiring replacement sources can buy newly manufactured ceramic-based sources with activities up to 50 Ci, but these have a lower specific activity than previous CsCl sources. Higher activity CsCl sources (up to 1000 Ci) must be recovered from decommissioned irradiators, but the supply is very limited. He emphasized that transitioning away from cesium-137 without first validating alternative calibration approaches would compromise measurement traceability.

Joel Beazley (University of Oxford and United Kingdom Health Security Agency) presented a feasibility study on the use of alanine dosimeters embedded into identification cards for estimating radiation exposure following a radiological emergency, allowing faster population triage than conventional biodosimetry. Monte Carlo simulations showed that body attenuation can significantly affect the measured doses (requiring corrections of up to a factor of 100 for photon energies <0.4 MeV), making individual dose estimates unreliable for highly directional or short time-scale exposures. However, the approach may be useful when applied to groups of individuals and combined with positioning information. Longer isotropic exposures would only need modest correction factors of 1.4–1.7 depending on the photon energy and where on the body the identification cards are worn.

This session underscored the need for robust performance data, validated modeling, and traceable measurement methods to build confidence in emerging technologies.

4. POSTER SESSIONS

Poster presentations were an important and lively part of the CIRMS 2026 meeting. A total of 28 posters were presented on topics such as space charge dynamics in measurements of UHDR beams, structural changes in lignin following electron beam irradiation, updates to radionuclide calibration services at NIST, and more. The poster presentations were organized into two interactive sessions. Prior to each session, presenters were invited to participate in a “poster blitz” in which they delivered concise, two-minute oral presentations highlighting their work to the meeting participants at large. The blitz served to stimulate discussion during the interactive poster sessions that followed. A complete listing of the poster presentations is in the Supplementary Material.

5. AWARDS

5.1. Randall S. Caswell Award

The Caswell Award is CIRMS’s highest award and is given periodically to individuals who have made significant contributions to ionizing radiation measurements and standards for the Nation, and who have actively furthered the mission of CIRMS through leadership, participation, research, and/or mentoring. The namesake of the award is Randall (“Randy”) S. Caswell, one of the principal founders of CIRMS and former head of the NIST Ionizing Radiation Division (now called Radiation Physics Division). Because the 2025 meeting was postponed, both the 2025 and 2026 Caswell Awards were presented at the CIRMS 2026 meeting.

The 2025 Caswell Award was presented to Nolan E. Hertel (Georgia Institute of Technology, retired) for his contributions to radiation protection and measurement science. As a pioneer in neutron dosimetry and radiation shielding, he helped shape international standards through leadership on key committees, including the American National Standards Institute (ANSI)/American Nuclear Society (ANS) 6.1.1 working group on fluence-to-dose conversion coefficients (American Nuclear Society 2020; Mille et al. 2018) and the development of International Commission on Radiation Units and Measurements (ICRU) Report 95 (International Commission on Radiation Units and Measurements 2020) which established operational quantities for external radiation exposure. His tenure as CIRMS President (2008–2009) advanced national measurement standards, while three decades at Georgia Institute of Technology and his work at Oak Ridge National Laboratory have left an indelible mark on the field. His dedication to mentoring over 80 graduate students, coupled with innovations in detector materials and radiation detection instruments, exemplifies the kind of impactful leadership that the Caswell Award celebrates.

The 2026 Caswell Award was given to Mark S. Driscoll (State University of New York College of Environmental Science and Forestry (SUNY ESF)) in recognition of his outstanding contributions to the field, particularly through his leadership as Director of the Ultraviolet Light and Electron Beam Technology Center at the SUNY ESF, as well as his extensive research in radiation chemistry, electron-beam processing, and materials science. His research accomplishments span a wide range of applications, including the development of X-ray-cured carbon-fiber composites for vehicle applications (Herer et al. 2009), X-ray and electron-beam processing methods to improve the material properties of wood and wood–plastic composites (Cleland et al. 2009; Driscoll et al. 2009; Palm et al. 2015), and radiation-based technologies for degrading contaminants in wastewater. His dual role as a researcher and educator, together with his longstanding engagement in CIRMS, including serving as CIRMS President (2017–2018), exemplifies the spirit of the award.

Both Nolan and Mark received award plaques and gave lectures highlighting not only their scientific achievements, but also the mentors, collaborators, and students who helped shape their decades-long careers in radiation science.

5.2. Marshall Cleland Early Career Investigator Award

CIRMS recognizes the importance of supporting early career investigators working in the field of ionizing radiation measurements and standards. As such, in 1999, CIRMS initiated an award program to highlight the research accomplishments of early career scientists. In 2024, the award was renamed in honor of Marshall Cleland, who served as the first president of CIRMS and co-founder of Radiation Dynamics Inc which sponsored the award for many years. Marshall was a respected physicist whose contributions to particle accelerator development, radiation measurement science, and mentorship of early career scientists had a lasting impact on the field. John Logar (Johnson & Johnson) gave a commemorative presentation on Marshall’s legacy.

The Marshall Cleland Early Career Investigator Award is open to individuals currently enrolled in an academic graduate program or within one year of completing a terminal master’s or doctoral degree program. Applicants submit extended abstracts for poster presentation at the meeting describing their work and its relevance to the CIRMS mission. A committee of subject matter experts evaluates the abstracts, and the top-scoring submissions receive monetary awards. In 2026, the first recipients of the Marshall Cleland Early Career Investigator Awards were:

1. Andrew Friberg (University of Pennsylvania) for his abstract titled “Modeling lateral charge dynamics and space-charge screening in ionization chambers under UHDR proton pencil beam”

2. Karen Rex Pius Vincent (University of Wisconsin–Madison) for her abstract titled “Nondestructive volume determination of commercial ionization chamber using various micro-CTs”

3. Likhitha Polepalli (University of Wisconsin–Madison) for her abstract titled “Evaluating source geometry dependencies in Lu-177 measurements with air communicating well-type ionization chambers”

5.3. Radiation Technology Essay Competition

In 2026, CIRMS offered a new essay competition to better engage with students not directly involved in ionizing radiation research, with the goal of improving student engagement and literacy in radiation science and technology. Students from high school through undergraduate level were invited to submit a brief essay on an ionizing radiation technology or process, describing the underlying technical principles, the type of radiation involved, and its societal benefits. A committee of subject matter experts evaluated the essays and accompanying poster presentations, and the top-scoring submission received a monetary award. The CIRMS 2026 Radiation Technology Essay Award was given to Lindsey Wright (University of Maryland, College Park) for her essay on “Quantifying arsenic in rice using neutron activation analysis.”

6. DISCUSSION AND CONCLUSIONS

The CIRMS 2026 meeting highlighted the breadth and urgency of current challenges in ionizing radiation measurements and standards. Across the plenary, breakout, and poster sessions, a consistent theme emerged: advances in radiation applications—ranging from FLASH radiotherapy and fusion energy to nuclear waste management and biodosimetry—are outpacing the development of the supporting measurement infrastructure and standardized methodologies. The topics presented represent a subset of the broader measurement and standards needs facing the ionizing radiation community. Numerous additional challenges in radioactivity measurements, radiation dosimetry, neutron physics, and related metrology infrastructure need attention. Addressing these gaps will require coordinated efforts across academia, government, and industry, reinforcing the vital role of CIRMS as a convening body for consensus-building and strategic direction.

Key needs identified during the meeting included improved neutron dosimetry and associated biological effectiveness metrics, development of traceable standards for UHDR radiation, enhanced support for primary standards laboratories, and innovation in detector technologies for both clinical and field applications. In parallel, emerging areas such as biologically driven dosimetry (e.g., the proposed dizdar unit), integration of Monte Carlo modeling with experimental validation, and advancements in radiation sterilization point to a growing need to bridge physical and biological measurement frameworks.

The discussions at the meeting also emphasized the importance of strengthening communication with policymakers and funding agencies to support sustained investment in radiation metrology (DeWerd and Khan 2025). As highlighted in the keynote on federal advocacy, articulating clear, consensus-driven priorities—such as those captured in the Needs Report—is essential for advancing national capabilities. Furthermore, although CIRMS originated as a U.S.-focused organization, many of the identified needs are international in scope and require global coordination among standards laboratories, regulators, scientific societies, and end-users.

Equally important is the cultivation of the next generation of scientists, as demonstrated by the strong participation in the Marshall Cleland Early Career Investigator competition. Continued support for early career scientists is critical for keeping innovation and expertise in this highly interdisciplinary field.

In conclusion, the CIRMS 2026 meeting reaffirmed the organization’s mission to identify, prioritize, and communicate needs in ionizing radiation measurements and standards. The outcomes of this meeting will directly inform the next Needs Report, providing a roadmap for future research, infrastructure development, and policy engagement. Through sustained collaboration, strategic investment, and international engagement, CIRMS will continue to play a vital role in ensuring that radiation measurement science evolves alongside emerging technologies and societal needs.