Ph.D. Thesis Defense by Robert W. Simpkins
Friday, August 23, 2002

(Dr. Nolan Hertel, advisor)

"Neutron Organ Dose and the Influence of Adipose Tissue"


MIRD-V based mathematical anthropomorphic phantoms have been modified to include human adipose tissue deposits. Models have been prepared depicting adipose tissue distribution for an adult male, adult female and post menopausal female. Organ absorbed dose and effective dose conversion coefficients have been prepared using Monte Carlo transport analysis. Parallel beams of monoenegetic neutrons ranging in energies from thermal to 10 MeV have been used to evaluate the influence of adipose tissue. Neutron incidences have been evaluated for standard irradiation geometires: anterior-posterior, posterior-anterior, left lateral, right lateral and rotational. Adipose tissue phantom results have been compared with data obtained from MIRD-V reference gender-specific phantoms. These comparisons indicate that further refinements of the existing reference phantoms are warranted and that studies with more detailed adipose tissue phantoms are needed.