Advanced Technologies in Radiation Research.

The U.S. Government is committed to maintaining a robust research program that supports a portfolio of scientific experts who are investigating the biological effects of radiation exposure. On August 17 and 18, 2023, the Radiation and Nuclear Countermeasures Program, within the National Institute of Allergy and Infectious Diseases, National Institutes of Health (NIH), partnered with the National Cancer Institute, NIH, the National Aeronautics and Space Administration, and the Radiation Injury Treatment Network to convene a workshop titled, Advanced Technologies in Radiation Research (ATRR), which focused on the use of advanced technologies under development or in current use to accelerate radiation research. This meeting report provides a comprehensive overview of the research presented at the workshop, which included an assembly of subject matter experts from government, industry, and academia. Topics discussed during the workshop included assessments of acute and delayed effects of radiation exposure using modalities such as clustered regularly interspaced short palindromic repeats (CRISPR) - based gene editing, tissue chips, advanced computing, artificial intelligence, and immersive imaging techniques. These approaches are being applied to develop products to diagnose and treat radiation injury to the bone marrow, skin, lung, and gastrointestinal tract, among other tissues. The overarching goal of the workshop was to provide an opportunity for the radiation research community to come together to assess the technological landscape through sharing of data, methodologies, and challenges, followed by a guided discussion with all participants. Ultimately, the organizers hope that the radiation research community will benefit from the workshop and seek solutions to scientific questions that remain unaddressed. Understanding existing research gaps and harnessing new or re-imagined tools and methods will allow for the design of studies to advance medical products along the critical path to U.S. Food and Drug Administration approval.

Radiation-induced pulmonary fibrosis: roles of therapy-induced senescence and microRNAs.

PURPOSE: Progressive, irreversible radiation-induced pulmonary fibrosis (RIPF) is a clinically significant intermediate- to a late-occurring side effect of radiotherapy. Known mechanisms of RIPF include oxidative stress-induced activation of TGF-ß with activation of SMAD signaling, TNF-α elaboration, and activation of the Angiotensin Converting Enzyme (ACE) mediated production of angiotensin II with resulting activation of profibrotic cytokine signaling and vasoconstriction. The pioneering work of John Moulder, to whom this paper is dedicated, and several of his colleagues demonstrated that inhibiting the conversion of ACE with drugs such as Captopril, Enalapril, and Losartan can ameliorate radiation fibrosis in various tissues. While this work led several groups to probe mechanism-based pharmacological mitigation of RIPF, in this article, we explore and discuss the roles of microRNAs (miRNA) and therapy-induced senescence (TIS) in the pathogenesis of and potential biomarkers for RIPF. CONCLUSION: Our analysis of the published literature in the last decade on RIPF, miRNA, and TIS identifies TIS as a mechanism in the onset and progression of RIPF, which is regulated through several miRNAs. This work may lead to the discovery and development of the next generation of miRNA therapeutics and/or the repurposing of approved pharmaceutical agents and the development of early biomarker panels to predict RIPF.

Moving Forward in the Next Decade: Radiation Oncology Sciences for Patient-Centered Cancer Care.

In a time of rapid advances in science and technology, the opportunities for radiation oncology are undergoing transformational change. The linkage between and understanding of the physical dose and induced biological perturbations are opening entirely new areas of application. The ability to define anatomic extent of disease and the elucidation of the biology of metastases has brought a key role for radiation oncology for treating metastatic disease. That radiation can stimulate and suppress subpopulations of the immune response makes radiation a key participant in cancer immunotherapy. Targeted radiopharmaceutical therapy delivers radiation systemically with radionuclides and carrier molecules selected for their physical, chemical, and biochemical properties. Radiation oncology usage of "big data" and machine learning and artificial intelligence adds the opportunity to markedly change the workflow for clinical practice while physically targeting and adapting radiation fields in real time. Future precision targeting requires multidimensional understanding of the imaging, underlying biology, and anatomical relationship among tissues for radiation as spatial and temporal "focused biology." Other means of energy delivery are available as are agents that can be activated by radiation with increasing ability to target treatments. With broad applicability of radiation in cancer treatment, radiation therapy is a necessity for effective cancer care, opening a career path for global health serving the medically underserved in geographically isolated populations as a substantial societal contribution addressing health disparities. Understanding risk and mitigation of radiation injury make it an important discipline for and beyond cancer care including energy policy, space exploration, national security, and global partnerships.

Medical countermeasures for radiation induced health effects: report of an Interagency Panel Session held at the NASA Human Research Program Investigator's Workshop, 26 January 2017.

An Interagency Panel Session organized by the NASA Human Research Program (HRP) Space Radiation Program Element (SRPE) was held during the NASA HRP Investigator's Workshop (IWS) in Galveston, Texas on 26 January 2017 to identify complementary research areas that will advance the testing and development of medical countermeasures (MCMs) in support of radioprotection and radiation mitigation on the ground and in space. There were several areas of common interest identified among the various participating agencies. This report provides a summary of the topics discussed by each agency along with potential areas of intersection for mutual collaboration opportunities. Common goals included repurposing of pharmaceuticals, nutraceuticals for use as radioprotectors and/or mitigators, low-dose/chronic exposure paradigms, late effects post-radiation exposure, mixed-field exposures of gamma-neutron, performance decrements, and methods to determine individual exposure levels.

Development of Novel Radiosensitizers through the National Cancer Institute's Small Business Innovation Research Program.

While radiosensitizing chemotherapy has improved survival for several types of cancer, current chemoradiation regimens remain ineffective for many patients and have substantial toxicities. Given the strong need for the development of novel radiosensitizers to further improve patient outcomes, the Radiation Research Program (RRP) and the Small Business Innovation Research (SBIR) in the National Cancer Institute (NCI) issued a Request for Proposals (RFP) through the NCI SBIR Development Center's contracts pathway. We sought to determine the research outcomes for the NCI SBIR Development Center's funded proposals for the development of radiosensitizers. We identified SBIR-funded contracts and grants for the development of radiosensitizers from 2009 to 2018 using the National Institutes of Health (NIH) Reporter database. Research outcomes of the NCI SBIR Development Center-funded proposals were determined using a comprehensive internet search. We searched PubMed, clinicaltrials.gov, company websites and google.com for research articles, abstracts and posters, clinical trials, press releases and other news, related to progress in the development of funded radiosensitizers. To protect the intellectual property of the investigators and small businesses, all information obtained and reported is publicly available. The SBIR Program has funded four contracts and 11 grants for the development of novel radiosensitizers. Two companies have received phase IIb bridge awards. Overall, 50% of companies (6/12) have successfully advanced their investigational drugs into prospective clinical trials in cancer patients, and all but one company are investigating their drug in combination with radiation therapy as described in the NCI SBIR Development Center proposal. To date, only one company has initiated a randomized trial of standard of care with or without their radiosensitizer. In conclusion, the NCI SBIR Development Center has funded the development of novel radiosensitizers leading to clinical trials of novel drugs in combination with radiation therapy. Continued follow-up is needed to determine if any of these novel radiosensitizers produce improved tumor control and/or overall survival.

Radiation Biomarkers: Can Small Businesses Drive Accurate Radiation Precision Medicine?

Radiation therapy is an essential component of cancer treatment. Currently, tumor control and normal tissue complication probabilities derived from a general patient population guide radiation treatment. Its outcome could be improved if radiation biomarkers could be incorporated into approaches to treatment. A substantial number of cancer patients suffer from side effects of radiation therapy. These side effects can result in treatment interruption. Such unplanned treatment interruptions not only jeopardize anticancer treatment efficacy but also result in poor post-treatment quality-of-life. To develop and translate radiation biomarkers for clinical use, NCI's Radiation Research Program, in collaboration with the Small Business Innovation Research Development Center, funded four small businesses through the request for proposals after peer review during 2015-2019. Here, we summarize publicly available information on intellectual property rights, the status of development, ongoing clinical trials, success in obtaining financing and regulatory approval. An analysis of publicly available information indicates all four companies have completed phase I of SBIR funding and advanced to further development, validation and clinical trials with phase II SBIR funding. These biomarkers are: 1. A panel of genomic biomarkers of radiation response to predict toxicity and radioimmune response (MiraDx Inc., Los Angeles, CA); 2. A multiplex assay for single nucleotide polymorphism (SNP) biomarkers of radiation sensitivity to identify a subset of prostate cancer patients for which radiotherapy is contraindicated (L2 Diagnostics, New Haven, CT); 3. A cell-free DNA assay in blood to measure tissue damage shortly after radiation exposure (DiaCarta Inc., Richmond, CA); and 4. A metabolomic/lipidomic assay to predict late effects that adversely affect quality-of-life among patients treated with radiation for prostate cancer (Shuttle Pharmaceuticals, Rockville, MD). This work also provides a bird's eye view of the process of developing radiation biomarkers for use in radiation oncology clinics, some of the challenges and future directions.

Decreasing the Toxicity of Radiation Therapy: Radioprotectors and Radiomitigators Being Developed by the National Cancer Institute Through Small Business Innovation Research Contracts.

PURPOSE: The use of radioprotectors and radiomitigators could improve the therapeutic index of radiation therapy. With the intention of accelerating translation of radiation-effect modulators (radioprotectors and mitigators), the Radiation Research Program and SBIR (Small Business Innovation Research) Development Center within the National Cancer Institute issued 4 Requests for Proposals (RFPs) from 2010 to 2013. Twelve SBIR contract awards in total were made in response to the 4 RFPs from September 2011 through September 2014. Here, we provide an update on the status of SBIR contract projects for the development of radiation-effect modulators. METHODS AND MATERIALS: To assess the status of research and development efforts under the 4 RFPs on radiation-effect modulators, we searched PubMed for research articles, google.com for published abstracts, clinicaltrials.gov for ongoing or completed clinical trials, and company websites for press releases and other news. All information obtained and reported here is publicly available and thus protects the intellectual property of the investigators and companies. RESULTS: Of the 12 SBIR projects funded, 5 (42%) transitioned successfully from phase 1 to phase 2 SBIR funding, and among the Fast-Track contracts, this rate was 100% (3 of 3). The Internet search identified 3 abstracts and 6 publications related to the aims of the SBIR contracts. One-third of the companies (4 of 12) have successfully launched a total of 8 clinical trials to demonstrate the safety and efficacy of their investigational agents. Two drugs are in clinical trials for their indication as a radioprotector, and 2 drugs are under evaluation for their anticancer properties (an immunomodulator and a small molecule inhibitor). CONCLUSIONS: The National Cancer Institute's SBIR has provided pivotal funding to small businesses for the development of radioprotectors and radiomitigators, which resulted in multiple early-phase clinical trials. Longer follow-up is needed to determine the full impact of these novel therapeutics that enter clinical practice.

Radiation-Induced Fibrosis: Mechanisms and Opportunities to Mitigate. Report of an NCI Workshop, September 19, 2016.

A workshop entitled "Radiation-Induced Fibrosis: Mechanisms and Opportunities to Mitigate" (held in Rockville, MD, September 19, 2016) was organized by the Radiation Research Program and Radiation Oncology Branch of the Center for Cancer Research (CCR) of the National Cancer Institute (NCI), to identify critical research areas and directions that will advance the understanding of radiation-induced fibrosis (RIF) and accelerate the development of strategies to mitigate or treat it. Experts in radiation biology, radiation oncology and related fields met to identify and prioritize the key areas for future research and clinical translation. The consensus was that several known and newly identified targets can prevent or mitigate RIF in pre-clinical models. Further, basic and translational research and focused clinical trials are needed to identify optimal agents and strategies for therapeutic use. It was felt that optimally designed preclinical models are needed to better study biomarkers that predict for development of RIF, as well as to understand when effective therapies need to be initiated in relationship to manifestation of injury. Integrating appropriate endpoints and defining efficacy in clinical trials testing treatment of RIF were felt to be critical to demonstrating efficacy. The objective of this meeting report is to (a) highlight the significance of RIF in a global context, (b) summarize recent advances in our understanding of mechanisms of RIF,

Improving the Predictive Value of Preclinical Studies in Support of Radiotherapy Clinical Trials.

There is an urgent need to improve reproducibility and translatability of preclinical data to fully exploit opportunities for molecular therapeutics involving radiation and radiochemotherapy. For in vitro research, the clonogenic assay remains the current state-of-the-art of preclinical assays, whereas newer moderate and high-throughput assays offer the potential for rapid initial screening. Studies of radiation response modification by molecularly targeted agents can be improved using more physiologic 3D culture models. Elucidating effects on the cancer stem cells (CSC, and CSC-like) and developing biomarkers for defining targets and measuring responses are also important. In vivo studies are necessary to confirm in vitro findings, further define mechanism of action, and address immunomodulation and treatment-induced modification of the microenvironment. Newer in vivo models include genetically engineered and patient-derived xenograft mouse models and spontaneously occurring cancers in domesticated animals. Selection of appropriate endpoints is important for in vivo studies; for example, regrowth delay measures bulk tumor killing, whereas local tumor control assesses effects on CSCs. The reliability of individual assays requires standardization of procedures and cross-laboratory validation. Radiation modifiers must be tested as part of clinical standard of care, which includes radiochemotherapy for most tumors. Radiation models are compatible with but also differ from those used for drug screening. Furthermore, the mechanism of a drug as a chemotherapeutic agent may be different from its interaction with radiation and/or radiochemotherapy. This provides an opportunity to expand the use of molecular-targeted agents. Clin Cancer Res; 22(13); 3138-47. ©2016 AACR.

High-throughput sample processing and sample management; the functional evolution of classical cytogenetic assay towards automation.

High-throughput individual diagnostic dose assessment is essential for medical management of radiation-exposed subjects after a mass casualty. Cytogenetic assays such as the Dicentric Chromosome Assay (DCA) are recognized as the gold standard by international regulatory authorities. DCA is a multi-step and multi-day bioassay. DCA, as described in the IAEA manual, can be used to assess dose up to 4-6 weeks post-exposure quite accurately but throughput is still a major issue and automation is very essential. The throughput is limited, both in terms of sample preparation as well as analysis of chromosome aberrations. Thus, there is a need to design and develop novel solutions that could utilize extensive laboratory automation for sample preparation, and bioinformatics approaches for chromosome-aberration analysis to overcome throughput issues. We have transitioned the bench-based cytogenetic DCA to a coherent process performing high-throughput automated biodosimetry for individual dose assessment ensuring quality control (QC) and quality assurance (QA) aspects in accordance with international harmonized protocols. A Laboratory Information Management System (LIMS) is designed, implemented and adapted to manage increased sample processing capacity, develop and maintain standard operating procedures (SOP) for robotic instruments, avoid data transcription errors during processing, and automate analysis of chromosome-aberrations using an image analysis platform. Our efforts described in this paper intend to bridge the current technological gaps and enhance the potential application of DCA for a dose-based stratification of subjects following a mass casualty. This paper describes one such potential integrated automated laboratory system and functional evolution of the classical DCA towards increasing critically needed throughput.

Radioprotectors and Radiomitigators for Improving Radiation Therapy: The Small Business Innovation Research (SBIR) Gateway for Accelerating Clinical Translation.

Although radiation therapy is an important cancer treatment modality, patients may experience adverse effects. The use of a radiation-effect modulator may help improve the outcome and health-related quality of life (HRQOL) of patients undergoing radiation therapy either by enhancing tumor cell killing or by protecting normal tissues. Historically, the successful translation of radiation-effect modulators to the clinic has been hindered due to the lack of focused collaboration between academia, pharmaceutical companies and the clinic, along with limited availability of support for such ventures. The U.S. Government has been developing medical countermeasures against accidental and intentional radiation exposures to mitigate the risk and/or severity of acute radiation syndrome (ARS) and the delayed effects of acute radiation exposures (DEARE), and there is now a drug development pipeline established. Some of these medical countermeasures could potentially be repurposed for improving the outcome of radiation therapy and HRQOL of cancer patients. With the objective of developing radiation-effect modulators to improve radiotherapy, the Small Business Innovation Research (SBIR) Development Center at the National Cancer Institute (NCI), supported by the Radiation Research Program (RRP), provided funding to companies from 2011 to 2014 through the SBIR contracts mechanism. Although radiation-effect modulators collectively refer to radioprotectors, radiomitigators and radiosensitizers, the focus of this article is on radioprotection and mitigation of radiation injury. This specific SBIR contract opportunity strengthened existing partnerships and facilitated new collaborations between academia and industry. In this commentary, we assess the impact of this funding opportunity, outline the review process, highlight the organ/site-specific disease needs in the clinic for the development of radiation-effect modulators, provide a general understanding of a framework for gathering preclinical and clinical evidence to obtain regulatory approval and provide a basis for broader venture capital needs and support from pharmaceutical companies to fully capitalize on the advances made thus far in this field.

Radiation-induced brain damage, impact of Michael Robbins' work and the need for predictive biomarkers.

PURPOSE: To review the literature on radiation-induced normal tissue injury in the context of treatment of primary and metastatic brain tumors with a focus on Michael Robbins' work on mechanisms of injury and approaches to mitigation, and also to identify other potential opportunities to improve treatment outcome and quality of life (QOL). BACKGROUND: Brain tumors remain a significant challenge for patients, their families, the physicians treating them, and researchers seeking more effective treatments. Current treatment of brain tumors involves combinations of radiotherapy with surgery, chemotherapy, and molecularly targeted agents. As patient survival improves with advances in treatment there is an increasing concern for the cognitive deficits that may become apparent months or years after treatment some of which are related to radiation-induced brain damage. One area of Michael Robbins' research was unraveling the mechanisms of radiation-induced cognitive deficits, which formed the basis for the development of some mitigators of radiation injury. Extrapolating from this, new opportunities to identify and develop putative predictive biomarkers of radiation-induced brain damage can be explored. CONCLUSIONS: Predictive biomarkers of radiation-induced brain injury may enable stratifying patients for customization of treatment and thus aid in improving the QOL and possibly prolonging survival. Here we discuss the challenges involved in leveraging recent advances in radiation-specific biomarker research and translating them to radiotherapy, which for the foreseeable future is likely to remain a cornerstone of the treatment of brain tumors.

Mitigating the risk of radiation-induced cancers: limitations and paradigms in drug development.

The United States radiation medical countermeasures (MCM) programme for radiological and nuclear incidents has been focusing on developing mitigators for the acute radiation syndrome (ARS) and delayed effects of acute radiation exposure (DEARE), and biodosimetry technologies to provide radiation dose assessments for guiding treatment. Because a nuclear accident or terrorist incident could potentially expose a large number of people to low to moderate doses of ionising radiation, and thus increase their excess lifetime cancer risk, there is an interest in developing mitigators for this purpose. This article discusses the current status, issues, and challenges regarding development of mitigators against radiation-induced cancers. The challenges of developing mitigators for ARS include: the long latency between exposure and cancer manifestation, limitations of animal models, potential side effects of the mitigator itself, potential need for long-term use, the complexity of human trials to demonstrate effectiveness, and statistical power constraints for measuring health risks (and reduction of health risks after mitigation) following relatively low radiation doses (<0.75 Gy). Nevertheless, progress in the understanding of the molecular mechanisms resulting in radiation injury, along with parallel progress in dose assessment technologies, make this an opportune, if not critical, time to invest in research strategies that result in the development of agents to lower the risk of radiation-induced cancers for populations that survive a significant radiation exposure incident.

Premature chromosome condensation in human resting peripheral blood lymphocytes without mitogen stimulation for chromosome aberration analysis using specific whole chromosome DNA hybridization probes.

We have previously described a unique, simple, and rapid method for inducing premature chromosome condensation (PCC) in "resting" human peripheral blood lymphocytes (HPBLs) without mitogen stimulation and an approach for studying numerical changes and/or structural aberrations involving a specific pair of human chromosomes. The current protocol incorporates improvements that provide better PCC, incorporates a high-throughput automated sample preparation unit and metaphase harvester to minimize manual labor and improve quality, and supports simultaneous painting of multiple sets of human autosomes in interphase nuclei. To induce PCC, isolated HPBLs are incubated at 37 °C in cell culture medium supplemented with a phosphatase inhibitor (okadaic acid or calyculin A), adenosine triphosphate, and p34(cdc2)/cyclin B kinase (an essential component of mitosis-promoting factor) for a short period of time. PCC spreads are prepared on glass slides using a humidity- and temperature-controlled chamber (an auto-spreader) after a brief hypotonic treatment and fixation. Aberrations involving specific sets of painted human chromosome are analyzed using fluorescence microscopy. Each of the normal (undamaged) painted homologous chromosome pairs displays two fluorescent spots, whereas cells with numerical and/or structural aberration involving specific painted chromosome sets show deviation in the number of fluorescent spots. The identification and quantification of aberration involving specific chromosomes in interphase nuclei have important applications in radiobiology, toxicology, radiation therapeutics, and cancer research.

Assessment of biodosimetry methods for a mass-casualty radiological incident: medical response and management considerations.

Following a mass-casualty nuclear disaster, effective medical triage has the potential to save tens of thousands of lives. In order to best use the available scarce resources, there is an urgent need for biodosimetry tools to determine an individual's radiation dose. Initial triage for radiation exposure will include location during the incident, symptoms, and physical examination. Stepwise triage will include point of care assessment of less than or greater than 2 Gy, followed by secondary assessment, possibly with high throughput screening, to further define an individual's dose. Given the multisystem nature of radiation injury, it is unlikely that any single biodosimetry assay can be used as a standalone tool to meet the surge in capacity with the timeliness and accuracy needed. As part of the national preparedness and planning for a nuclear or radiological incident, the authors reviewed the primary literature to determine the capabilities and limitations of a number of biodosimetry assays currently available or under development for use in the initial and secondary triage of patients. Understanding the requirements from a response standpoint and the capability and logistics for the various assays will help inform future biodosimetry technology development and acquisition. Factors considered include: type of sample required, dose detection limit, time interval when the assay is feasible biologically, time for sample preparation and analysis, ease of use, logistical requirements, potential throughput, point-of-care capability, and the ability to support patient diagnosis and treatment within a therapeutically relevant time point.

Normal tissue protection for improving radiotherapy: Where are the Gaps?

Any tumor could be controlled by radiation therapy if sufficient dose were delivered to all tumor cells. Although technological advances in physical treatment delivery have been developed to allow more radiation dose conformity, normal tissues are invariably included in any radiation field within the tumor volume and also as part of the exit and entrance doses relevant for particle therapy. Mechanisms of normal tissue injury and related biomarkers are now being investigated, facilitating the discovery and development of a next generation of radiation protectors and mitigators. Bringing recent research advances stimulated by development of radiation countermeasures for mass casualties, to clinical cancer care requires understanding the impact of protectors and mitigators on tumor response. These may include treatments that modify cellular damage and death processes, inflammation, alteration of normal flora, wound healing, tissue regeneration and others, specifically to counter cancer site-specific adverse effects to improve outcome of radiation therapy. Such advances in knowledge of tissue and organ biology, mechanisms of injury, development of predictive biomarkers and mechanisms of radioprotection have re-energized the field of normal tissue protection and mitigation. Since various factors, including organ sensitivity to radiation, cellular turnover rate, and differences in mechanisms of injury manifestation and damage response vary among tissues, successful development of radioprotectors/mitigators/treatments may require multiple approaches to address cancer site specific needs. In this review, we discuss examples of important adverse effects of radiotherapy (acute and intermediate to late occurring, when it is delivered either alone or in conjunction with chemotherapy, and important limitations in the current approaches of using radioprotectors and/or mitigators for improving radiation therapy. Also, we are providing general concepts for drug development for improving radiation therapy.

Biological Dosimetry by the Triage Dicentric Chromosome Assay - Further validation of International Networking.

Biological dosimetry is an essential tool for estimating radiation doses received to personnel when physical dosimetry is not available or inadequate. The current preferred biodosimetry method is based on the measurement of radiation-specific dicentric chromosomes in exposed individuals' peripheral blood lymphocytes. However, this method is labour-, time- and expertise-demanding. Consequently, for mass casualty applications, strategies have been developed to increase its throughput. One such strategy is to develop validated cytogenetic biodosimetry laboratory networks, both national and international. In a previous study, the dicentric chromosome assay (DCA) was validated in our cytogenetic biodosimetry network involving five geographically dispersed laboratories. A complementary strategy to further enhance the throughput of the DCA among inter-laboratory networks is to use a triage DCA where dose assessments are made by truncating the labour-demanding and time-consuming metaphase-spread analysis to 20 to 50 metaphase spreads instead of routine 500 to 1000 metaphase spread analysis. Our laboratory network also validated this triage DCA, however, these dose estimates were made using calibration curves generated in each laboratory from the blood samples irradiated in a single laboratory. In an emergency situation, dose estimates made using pre-existing calibration curves which may vary according to radiation type and dose rate and therefore influence the assessed dose. Here, we analyze the effect of using a pre-existing calibration curve on assessed dose among our network laboratories. The dose estimates were made by analyzing 1000 metaphase spreads as well as triage quality scoring and compared to actual physical doses applied to the samples for validation. The dose estimates in the laboratory partners were in good agreement with the applied physical doses and determined to be adequate for guidance in the treatment of acute radiation syndrome.