Semester of Graduation

Summer 2025

Degree

Master of Science (MS)

Department

Department of Physics and Astronomy

Document Type

Thesis

Abstract

Astronauts aboard the International Space Station (ISS) are chronically exposed to a complex space radiation environment composed of galactic cosmic rays (GCR), solar particles, and Earth's trapped radiation. These high-energy particles interact with spacecraft shielding, producing secondary particles that can penetrate inside and deposit energy in sensitive tissues. Although animal studies have been useful in assessing space radiation risks, anatomical and physiological differences limit their applicability to human anatomy especially neuroanatomy. To address this gap, we developed a computational framework to model radiation dose distribution within the human brain using Monte Carlo simulations in Particle and Heavy Ion Transport code System (PHITS). This study consists of three major components: (1) construction of an intravehicular (IV) radiation environment using an simplified shielding configuration and validated Low Earth Orbit (LEO) GCR spectrum; (2) simulation of dose deposition in both water and ICRP reference phantoms to assess spatial distribution; and (3) estimate the mean absorbed dose delivered to the sub-regions of the brain. By integrating accurate radiation transport physics with anatomically segmented geometry, this work enables region specific mapping of dose accumulation within the brain. The results will improve understanding of how radiation is distributed across different neural structures, serving as a foundation for future biological and risk-based evaluations.

Date

7-16-2025

Committee Chair

Solis, David

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