Space Radiation and Astronaut Health Managing and Communicating Cancer Risks (2021) / Chapter Skim
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4 Communicating About Radiation-Induced Cancer Risks
4 Communicating About Radiation-Induced Cancer Risks
Pages 71-94
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From page 71... ...
requested the committee to consider "how to express what is needed in the form of a radiation risk management process or approach NASA could apply to determine astronaut eligibility for crewed missions." This chapter focuses on this aspect of the study task and specifically on communicating with astronauts about the risks associated with exposure to space radiation. As NASA works to manage radiation-exposure health risks, it will be important for the agency to continue to adhere to the radiation safety principle of keeping radiation exposures as low as reasonably achievable (ALARA)
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From page 72... ...
assessment will be provided Waiver 95% CI for a 55-year-old male that accounts for sex and age. Career Exposure Medium Risk – Individual Assessment Moderate Level of Exposure Individual assessment will be provided At this threshold, an Effective Dose < 600 mSv that accounts for sex and age.
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From page 73... ...
Achieving these risk communication aims requires an understanding of the risks and the standard themselves, as well as comprehension of how astronauts understand and interpret the formal and informal communications about them. Achieving these aims is complicated by the dynamic nature of the risk communication situation, including but not limited to the evolution of radiation risk sciences, changes in the nature of space missions, diversification of the NASA Astronaut Corps, and the evolution of occupational exposure standards for terrestrial employees, which NASA may reference in developing risk management strategies.
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From page 74... ...
. Depending on its communication goals, NASA may wish to develop generic space radiation risk messages for public audiences, in addition to the targeted risk messages it uses to communicate the space radiation standard to NASA astronauts as a group and the tailored messages it uses for individual astronauts.
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From page 75... ...
. CONSIDERING NASA'S PROPOSED RISK COMMUNICATION TOOL FOR THE SPACE RADIATION STANDARD In public meetings, NASA presented this committee with a figure that presents the proposed space permissible exposure limit, as seen in Figure 4-1.1 The committee understands that this visual aid is intended as NASA's primary risk communication system for the updated space radiation standard.
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From page 76... ...
This framework assesses the source of the message, the content of the message, the format of the communication, and the anticipated effects of the communication on recipients. Source of the Message Presentations and materials provided to the committee by NASA show that both formal and informal communications with astronauts about radiation risks come from multiple sources including the Space Radiation Analysis Group at NASA, the Human System Risk Board, flight surgeons, and others.
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From page 77... ...
NASA's proposed individual risk assessment is differentiated from the general assessment only by taking into account sex and age. An individual astronaut who wishes to interpret his or her own spaceflight-attributable cancer radiation risks from a proposed mission might need not only specific information about dose and dose rate, but also information about the influence of nonmodifiable individual factors such as genetics and modifiable factors such as lifestyle and environmental factors that interact with spaceflight radiation, all of which contribute to their baseline cancer risk.
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From page 78... ...
For example, if a terrestrial worker was exposed to a hazard with a 2.7 percent REID, that would be more than an order of magnitude greater than the level deter mined by the U.S. Supreme Court to be acceptable for industrial workers.2 To help empower astronauts to understand the full picture of their cancer radiation risks, the background cancer risks in the population and risks from occupational radiation exposures can also be communicated in the context of factors that might influence the astronaut's cancer risk (e.g., family history, lifestyle factors)
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From page 79... ...
, it is helpful if the time interval is explicitly communicated. NASA also needs to be prepared to answer questions from astronauts on their radiation risk profile, which includes current and past occupational exposures as well as other radiation doses received from medical diagnostic and therapeutic procedures, naturally occurring radioactivity in the environment, and other sources.
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From page 80... ...
The extent to which this does or should influence interpretations of Figure 4-1 is not clear, as risk communication research is inconclusive on this topic (Budescu and Wallsten, 1995; Budescu et al., 2009; Padilla et al., 2020; Teigen and Løhre, 2017; van der Bles et al., 2019)
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From page 81... ...
. The committee reached the following conclusion: Conclusion II: NASA has proposed to use a traffic light color coded system to categorize and communicate space radiation risks.
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From page 82... ...
for the updated space radiation standard to do the following: • Assess and communicate the radiation risk at an individual level (as opposed to generic risk assessments) for all astronauts independent of the actual or projected radiation exposure and risk.
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From page 83... ...
• Communicate the uncertainties for the risk distribution using both uncertainty intervals and limits, and visual representations of the risk distribution such as probability density curves, histograms, or heat maps. • Address specific questions and concerns that individual astronauts may have regarding their overall health risks following communica tion of their actual or projected radiation dose, and help them place radiation risks into perspective compared to other mission risks.
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From page 84... ...
To do so, NASA should do the following: • Respond to questions from astronauts regarding their total radiation exposure, and help astronauts put their radiation-induced cancer risk in context. • Continue to discuss any changes in radiation risks as part of rou tine health briefings for the astronaut office, crews, and individual astronauts.
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From page 85... ...
To do this, HMTA standards, such as fitness for duty standards, are applied to individual astronauts to both protect the astronauts and also to assure they can perform at a level needed for any specific mission. NASA also establishes space permissible exposure limits (SPELs)
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From page 86... ...
In this instance, unlike employers subject to OSHA standards, NASA may seek to obtain permission for a mission waiver that would permit the agency to subject all volunteers for that mission to an unusual level of risk that would be unacceptable in less time-sensitive and critical missions. Waivers for specific missions and potentially for individual partici pation in any given mission were considered in depth by the Institute of Medicine's Committee on Ethics Principles and Guidelines for Health Standards for Long Duration and Exploration Spaceflights (IOM, 2014)
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From page 87... ...
The main purpose for an upper dose limit to the waiver is to provide additional protection to astronauts from the expected adverse health effects of high radiation doses. High radiation doses carry high risks for cancer induction in the future and could induce tissue reactions (deterministic effects)
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From page 88... ...
described the ethical principles serving as the foundation for this recommended stepwise process. The committee reached the following conclusion regarding NASA's waiver process: Conclusion IV: The committee recognizes that NASA's inclusion of the waiver in its space radiation risk management process may be necessary to maintain the flexibility for the agency to pursue missions in which astronauts are exposed to radiation doses that exceed its standard.
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From page 89... ...
Retired astronauts or astronauts in training may be a suitable population, as well as radiation professionals who have similar levels of expertise and numeracy. The committee makes the following recommendation: Recommendation 6: NASA should conduct research to develop evidence-based risk communication and the agency should develop a radiation risk communication research agenda to fill knowledge gaps such as (1)
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From page 90... ...
2017. Designing visual aids that promote risk literacy: A systematic review of health research and evidence-based design heuristics.
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From page 91... ...
2016. Personalized cancer risk assessments for space radiation exposures.
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From page 92... ...
Presenta tion to the Committee on Assessment of Strategies for Managing Cancer Risks Associated with Radiation Exposure During Crewed Space Missions, January 25. Severtson, D
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From page 93... ...
2020. Red for "stop": "Traffic-light" nutri tion labels decrease unhealthy food choices by increasing activity and connectivity in the frontal lobe.
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