Fluence-to-effective dose conversion coefficients for male astronauts

Area of Science:

• Space medicine
• Radiation physics
• Astrobiology

Background:

• Accurate estimation of astronaut radiation exposure in deep space is critical for ongoing space exploration.
• Current effective dose estimations (ICRP Publication 103) may be overly conservative for astronauts.
• Developing refined radiation risk assessment models is essential for crewed missions.

Purpose of the Study:

• To evaluate more realistic methods for calculating astronaut radiation doses in deep space.
• To compare different approaches for radiation risk estimation tailored to astronauts.
• To investigate the use of alternative dose metrics and weighting factors.

Main Methods:

• Utilizing the NASA concept relating radiation quality factor to linear energy transfer (LET) or Z*²/β².
• Applying tissue weighting coefficients averaged from a cohort of males similar to astronauts (NASA cohort, males aged 30-60, non-smokers).
• Calculating and comparing fluence-to-effective dose equivalent conversion coefficients specifically for astronauts.

Main Results:

• The effective dose based on ICRP Publication 103 provides a conservative estimate of astronaut radiation risk.
• Alternative methods, incorporating NASA's concept and specific weighting factors, offer a more realistic dose calculation.
• Calculated conversion coefficients show variations depending on the chosen methodology.

Conclusions:

• Current radiation risk assessment for astronauts may overestimate actual risk.
• Adopting NASA's concept and tailored weighting factors can lead to more accurate dose estimations.
• Further research into refined radiation dosimetry is crucial for long-duration spaceflight safety.