Design and dosimetry of a facility to study health effects following exposures to fission neutrons at low dose rates for long durations

Borak, Thomas B.; Heilbronn, L.; Krumland, Nathan; Weil, Michael M.

doi:10.1080/09553002.2019.1688884

Cited by 18 publications

(8 citation statements)

References 23 publications

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“…A recently developed method to simulate GCR in the NASA Space Radiation Laboratory (NSRL) (Simonsen et al, 2020) has shown promising results in cellular, tissue, and animal models (Malkani et al, 2020;Paul et al, 2020;Wuu et al, 2020). Currently available simulators of low-dose-rate irradiation include gamma ray flood sources (Bellone et al, 2016), a chronic neutron irradiation animal facility (Borak et al, 2019), and a series of low-dose, fractionated irradiations at NSRL.…”

Section: Challenges Of Simulating and Modeling The Space Environmentmentioning

confidence: 99%

Fundamental Biological Features of Spaceflight: Advancing the Field to Enable Deep-Space Exploration

Afshinnekoo

Scott

MacKay

et al. 2020

Cell

219

163

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Research on astronaut health and model organisms have revealed six features of spaceflight biology that guide our current understanding of fundamental molecular changes that occur during space travel. The features include oxidative stress, DNA damage, mitochondrial dysregulation, epigenetic changes (including gene regulation), telomere length alterations, and microbiome shifts. Here we review the known hazards of human spaceflight, how spaceflight affects living systems through these six fundamental features, and the associated health risks of space exploration. We also discuss the essential issues related to the health and safety of astronauts involved in future missions, especially planned long-duration and Martian missions.

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Section: Challenges Of Simulating and Modeling The Space Environmentmentioning

confidence: 99%

Fundamental Biological Features of Spaceflight: Advancing the Field to Enable Deep-Space Exploration

Afshinnekoo

Scott

MacKay

et al. 2020

Cell

219

163

View full text Add to dashboard Cite

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“…While neutrons represent only one element of the overall space radiation environment, shielding interactions will further elevate their proportion within the spacecraft effective radiation field [2,27,28] and neutrons remain one of the best proxies for modeling chronic particle radiation exposures [34]. Our study provides an important opportunity to compare the impacts of acute neutron irradiation against prior central nervous system disruptions observed after acute charged particle GCR exposure models.…”

Section: Discussionmentioning

confidence: 99%

“…Despite differences in the exact energy deposition patterns of charged particles and neutrons, both are elements of the space radiation environment that pose a potential risk to astronaut nervous system function. An advantage of neutron exposure studies over accelerator-based GCR simulations is that more realistic radiation dose-rates of around 0.5-1 mGy per day [1,33] can be simulated during chronic exposures lasting several months using 252 Cf sources [34]. We discovered that chronic, low dose (18 cGy) neutron irradiation at realistic low dose-rates resulted in suppressed hippocampal neuronal excitability, as well as perturbed hippocampal and cortical long-term potentiation [35].…”

Section: Introductionmentioning

confidence: 99%

Acute, Low-Dose Neutron Exposures Adversely Impact Central Nervous System Function

Klein

Alaghband

Doan

et al. 2021

IJMS

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A recognized risk of long-duration space travel arises from the elevated exposure astronauts face from galactic cosmic radiation (GCR), which is composed of a diverse array of energetic particles. There is now abundant evidence that exposures to many different charged particle GCR components within acute time frames are sufficient to induce central nervous system deficits that span from the molecular to the whole animal behavioral scale. Enhanced spacecraft shielding can lessen exposures to charged particle GCR components, but may conversely elevate neutron radiation levels. We previously observed that space-relevant neutron radiation doses, chronically delivered at dose-rates expected during planned human exploratory missions, can disrupt hippocampal neuronal excitability, perturb network long-term potentiation and negatively impact cognitive behavior. We have now determined that acute exposures to similar low doses (18 cGy) of neutron radiation can also lead to suppressed hippocampal synaptic signaling, as well as decreased learning and memory performance in male mice. Our results demonstrate that similar nervous system hazards arise from neutron irradiation regardless of the exposure time course. While not always in an identical manner, neutron irradiation disrupts many of the same central nervous system elements as acute charged particle GCR exposures. The risks arising from neutron irradiation are therefore important to consider when determining the overall hazards astronauts will face from the space radiation environment.

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“…Other models of radiation quality can be considered in future efforts, including the potential utilization of a radiation effects ratio (RER) in a narrow mission-relevant dose region [Shuryak et al 2017], mixedfield quality factors, and coupled mixed-field/dose-rate multiplicative factors. Results from on-going research studies at the NSRL and the Colorado State low dose neutron facility , Borak et al 2019 will supply a body of evidence to further inform model-form structure and the weighting (other than equal weighting) of various sub-model contributions accounting for mixed-field quality and dose-rate effects.…”

Section: VI Addressing Model-form Uncertaintymentioning

confidence: 99%

How certain are we? Development of an ensemble based framework for assessing astronaut cancer risks from space radiation

Simonsen

Slaba

2021

Preprint

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I.AbstractA new approach to NASA space radiation risk modeling has successfully extended the current NASA probabilistic cancer risk model to an ensemble framework able to consider sub-model parameter uncertainty as well as model-form uncertainty associated with differing theoretical or empirical formalisms. Ensemble methodologies are already widely used in weather prediction, modeling of infectious disease outbreaks, and certain terrestrial radiation protection applications to better understand how uncertainty may influence risk decision-making. Applying ensemble methodologies to space radiation risk projections offers the potential to efficiently incorporate emerging research results, allow for the incorporation of future models, improve uncertainty quantification for underlying sub-models, and reduce the impact of subjective bias on risk projections. Moreover, risk forecasting across an ensemble of multiple predictive models can provide stakeholders additional information on risk acceptance if current health/medical standards cannot be met for future space exploration missions, such as human missions to Mars. In this work, ensemble risk projections implementing multiple sub-models of radiation quality, dose and dose-rate effectiveness factors, excess risk, and latency as ensemble members are presented. Initial consensus methods for ensemble model weights and correlations to account for individual model bias are discussed. In these analyses, the ensemble forecast compares well to results from NASA’s current operational cancer risk projection model used to assess permissible mission durations for astronauts. However, a large range of projected risk values are obtained at the upper 95th confidence level where models must extrapolate beyond available biological data sets. Closer agreement is seen at the median + one sigma due to the inherent similarities in available models. Identification of potential new models, epidemiological data, and methods for statistical correlation between predictive ensemble members are discussed. Alternate ways of communicating risk and acceptable uncertainty with respect to NASA’s current permissible exposure limits are explored.

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Design and dosimetry of a facility to study health effects following exposures to fission neutrons at low dose rates for long durations

Cited by 18 publications

References 23 publications

Fundamental Biological Features of Spaceflight: Advancing the Field to Enable Deep-Space Exploration

Fundamental Biological Features of Spaceflight: Advancing the Field to Enable Deep-Space Exploration

Acute, Low-Dose Neutron Exposures Adversely Impact Central Nervous System Function

How certain are we? Development of an ensemble based framework for assessing astronaut cancer risks from space radiation

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