Improving astronaut cancer risk assessment from space radiation with an ensemble model framework

Simonsen, Lisa C.; Slaba, Tony C.

doi:10.1016/j.lssr.2021.07.002

Cited by 25 publications

(22 citation statements)

References 49 publications

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“…These should continue to be investigated by NASA and international partners through accelerator and spaceflight experiments to enable necessary model improvements. Still, these uncertainties are quite small compared to the landscape of epidemiological and radiobiological uncertainties clouding space radiation risk projections (Cucinotta et al., 2013; Simonsen & Slaba, 2021).…”

Section: Discussionmentioning

confidence: 99%

“…The current PEL for cancer is defined such that astronaut exposures do not exceed a 3% risk of exposure induced death (REID) evaluated at the upper 95% confidence level (CL) (equivalent to the 97.5th percentile) to account for significant uncertainties in the risk projection. The NASA cancer risk model (see Cucinotta et al., 2013 with modifications as described in the Appendix of Simonsen & Slaba, 2021) is used to calculate REID in accordance with the cancer PEL. The model translates human epidemiology data from a 1940s Japanese population who received an acute exposure of gamma and neutrons to a present‐day US healthy population (e.g., astronauts) who receive low dose‐rate, but possibly moderate total doses, of space radiation.…”

Section: Models and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…In the absence of solar storms, astronaut radiation exposure will come from galactic cosmic rays (GCR) and accumulate proportionally with mission duration. Health effects from prolonged exposure to GCR have been extensively studied over the past several decades with significant uncertainties and knowledge gaps remaining in risk projections primarily due to lack of directly relevant human data and limited ground-based experimental data (Cucinotta et al, 2013; NASA 2013;Simonsen & Slaba, 2021).The GCR environment comprises a complex mixture of fully ionized and highly energetic particles capable of penetrating spacecraft shielding and producing a cascade of secondary particles such as neutrons. Hydrogen and helium ions account for 87% and 12% of the total GCR fluence by mass, respectively.…”

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confidence: 99%

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Historical Reconstruction of Astronaut Cancer Risk: Context for Recent Solar Minima

Slaba

2021

Space Weather

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Human presence in space is expected to push beyond low Earth orbit (LEO) in the coming years with missions planned to the Moon and Mars (www.nasa.gov/what-is-artemis). In the absence of solar storms, astronaut radiation exposure will come from galactic cosmic rays (GCR) and accumulate proportionally with mission duration. Health effects from prolonged exposure to GCR have been extensively studied over the past several decades with significant uncertainties and knowledge gaps remaining in risk projections primarily due to lack of directly relevant human data and limited ground-based experimental data (Cucinotta et al., 2013; NASA 2013;Simonsen & Slaba, 2021).The GCR environment comprises a complex mixture of fully ionized and highly energetic particles capable of penetrating spacecraft shielding and producing a cascade of secondary particles such as neutrons. Hydrogen and helium ions account for 87% and 12% of the total GCR fluence by mass, respectively. The remaining 1% is covered by heavier ions with charge, Z, extending up to Z = 28 and beyond. The energy spectrum for each of these ions is quite broad with peak fluxes occurring just below 1 GeV/n and energies extending up to 1 TeV/n and beyond. GCR are modulated by the heliospheric magnetic field (HMF) on an approximate 11-year cycle. During solar minimum, the HMF is suppressed, and the flux of GCR ions below ∼5 GeV/n

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Section: Discussionmentioning

confidence: 99%

Section: Models and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Historical Reconstruction of Astronaut Cancer Risk: Context for Recent Solar Minima

Slaba

2021

Space Weather

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“…It is one of several commonly used metrics of excess lifetime risks from an exposure, and it specifically quantifies the increase in cause-specific deaths attributable to the exposure. The NASA Space Cancer Risk model was developed to assess REID and is specifically tailored to the space environment ( 14 , 47 ). The model uses approaches similar to those used by the National Institute of Health to assess human health risks from occupational, accidental, and medical radiation exposures on Earth ( 48 , 49 ).…”

Section: Current Management Of Space Radiation Health Risks By Nasamentioning

confidence: 99%

Cardiovascular Disease Risk Modeling for Astronauts: Making the Leap From Earth to Space

Huff

Plante

Blattnig

et al. 2022

Front. Cardiovasc. Med.

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NASA has recently completed several long-duration missions to the International Space Station and is solidifying plans to return to the Moon, with an eye toward Mars and beyond. As NASA pushes the boundaries of human space exploration, the hazards of spaceflight, including space radiation, levy an increasing burden on astronaut health and performance. The cardiovascular system may be especially vulnerable due to the combined impacts of space radiation exposure, lack of gravity, and other spaceflight hazards. On Earth, the risk for cardiovascular disease (CVD) following moderate to high radiation doses is well-established from clinical, environmental, and occupational exposures (largely from gamma- and x-rays). Less is known about CVD risks associated with high-energy charged ions found in space and increasingly used in radiotherapy applications on Earth, making this a critical area of investigation for occupational radiation protection. Assessing CVD risk is complicated by its multifactorial nature, where an individual's risk is strongly influenced by factors such as family history, blood pressure, and lipid profiles. These known risk factors provide the basis for development of a variety of clinical risk prediction models (CPMs) that inform the likelihood of medical outcomes over a defined period. These tools improve clinical decision-making, personalize care, and support primary prevention of CVD. They may also be useful for individualizing risk estimates for CVD following radiation exposure both in the clinic and in space. In this review, we summarize unique aspects of radiation risk assessment for astronauts, and we evaluate the most widely used CVD CPMs for their use in NASA radiation risk assessment applications. We describe a comprehensive dual-use risk assessment framework that supports both clinical care and operational management of space radiation health risks using quantitative metrics. This approach is a first step in using personalized medicine for radiation risk assessment to support safe and productive spaceflight and long-term quality of life for NASA astronauts.

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AOP report: Development of an adverse outcome pathway for deposition of energy leading to learning and memory impairment

Sleiman,

Miller,

Flores

et al. 2024

Environ and Mol Mutagen

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Understanding radiation‐induced non‐cancer effects on the central nervous system (CNS) is essential for the risk assessment of medical (e.g., radiotherapy) and occupational (e.g., nuclear workers and astronauts) exposures. Herein, the adverse outcome pathway (AOP) approach was used to consolidate relevant studies in the area of cognitive decline for identification of research gaps, countermeasure development, and for eventual use in risk assessments. AOPs are an analytical construct describing critical events to an adverse outcome (AO) in a simplified form beginning with a molecular initiating event (MIE). An AOP was constructed utilizing mechanistic information to build empirical support for the key event relationships (KERs) between the MIE of deposition of energy to the AO of learning and memory impairment through multiple key events (KEs). The evidence for the AOP was acquired through a documented scoping review of the literature. In this AOP, the MIE is connected to the AO via six KEs: increased oxidative stress, increased deoxyribonucleic acid (DNA) strand breaks, altered stress response signaling, tissue resident cell activation, increased pro‐inflammatory mediators, and abnormal neural remodeling that encompasses atypical structural and functional alterations of neural cells and surrounding environment. Deposition of energy directly leads to oxidative stress, increased DNA strand breaks, an increase of pro‐inflammatory mediators and tissue resident cell activation. These KEs, which are themselves interconnected, can lead to abnormal neural remodeling impacting learning and memory processes. Identified knowledge gaps include improving quantitative understanding of the AOP across several KERs and additional testing of proposed modulating factors through experimental work. Broadly, it is envisioned that the outcome of these efforts could be extended to other cognitive disorders and complement ongoing work by international radiation governing bodies in their review of the system of radiological protection.

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Improving astronaut cancer risk assessment from space radiation with an ensemble model framework

Cited by 25 publications

References 49 publications

Historical Reconstruction of Astronaut Cancer Risk: Context for Recent Solar Minima

Historical Reconstruction of Astronaut Cancer Risk: Context for Recent Solar Minima

Cardiovascular Disease Risk Modeling for Astronauts: Making the Leap From Earth to Space

AOP report: Development of an adverse outcome pathway for deposition of energy leading to learning and memory impairment

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