Semester of Graduation

Spring 2022

Degree

Master of Science (MS)

Department

Physics and Astronomy

Document Type

Thesis

Abstract

Purpose: To utilize advanced computational phantoms to determine absorbed dose, dose equivalent, and energy deposition following a space radiation exposure for human and mouse models.

Methods: The intravehicular space radiation environment measured on-board the International Space Station was generated using 3D Monte Carlo software. A number of particles equivalent to a single day's exposure in space were produced and reformatted such that they would produce an isotropic exposure for a given phantom. Tetrahedral mesh phantoms representing the 90th percentile for mass and height for the male and female Caucasian population were used as the human models while the Mouse Whole Body (MOBY) phantom was the mouse model. Absorbed dose and energy deposition for defined organs was determined for each model as well as the 3D dose deposition. A whole body dose for a single day's exposure was calculated and the whole body dose was visualized for all three models.

Results: The total body dose for the adult male and female phantoms were 0.3029 ± 0.0001 mGy/day and 0.3031 ± 0.0001 mGy/day, respectively. The whole body doses were within 10% of reported values from on-board the International Space Station (ISS). Conversely, the mouse model has a whole body dose of 39.76 ± 0.06 mGy/day, a higher value than what was expected.

Conclusions: The preliminary results discussed here supplies validity to the use of advanced computational phantoms to predict dose deposition following space radiation exposures. Whole-body daily dose rates fall within 10% of the measured dose rate on the ISS. Additionally, the mouse phantom predicted a different distribution of absorbed dose when compared to the human phantoms, as well a different whole-body absorbed dose.

Committee Chair

Chancellor, Jeffery

DOI

10.31390/gradschool_theses.5537

Available for download on Friday, April 07, 2023

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