Comparing water to DNA for simulation of Auger electron direct damage to DNA using Geant4

Author

Elliott Leonard

Publication Date

9-3-2013

Abstract

Typically water is used as an analog material for Deoxyribonucleic Acid (DNA) in Monte Carlo simulations of biological radiation interactions. Prior to this work, it was unclear whether water is an appropriate stand-in for DNA when simulating direct radiation damage on the nano scale. The increased interest in targeted tumor therapy using Auger electrons has requires an understand of the radiobological effectiveness of low energy electrons. A chromatin ber was constructed within the Geant4 simulation toolkit down to the molecular level. The Binary Encounter Bethe (BEB) model for electron impact ionization was added to the Geant4 Toolkit so the cross sections of molecules could be more accurately modeled. Validation was performed by comparing the BEB model to the ab initio Born model already implemented in Geant4. The BEB produces less ionization events but is effective at comparing DNA to water in this context by providing order-of-magnitude similarities in the results. Using the BEB model the number of double strand breaks for DNA was shown to be much greater than for water, indicating that water is not an effective analog for DNA.

Document Type

Thesis

Language

English

Degree Name

Nuclear Engineering

Level of Degree

Masters

Department Name

Nuclear Engineering

First Committee Member (Chair)

Hecht, Adam

Second Committee Member

de Almeida, Kenya

Recommended Citation

Leonard, Elliott. "Comparing water to DNA for simulation of Auger electron direct damage to DNA using Geant4." (2013). https://digitalrepository.unm.edu/ne_etds/32