Monte Carlo Studies of Radiation Therapy via X-Ray Radiosensitization of High-Z Nanomoieties and DNA Strand Breakups

The Monte Carlo code Geant4 was used to study methods to enhance DNA damage from tumor irradiation for cancer theranostics (therapy and diagnostics). The methods involved use of alternative X-ray sources and nanoparticles. Geant4 was used for simulations of the transmission and absorption of photons from quasi-monochromatic (QX), monochromatic (MX), and traditional broadband (BX) X-ray sources with heavy element nanoparticles, with an aim of increasing X-ray absorption [1]. The damage to cells was studied by looking at DNA strand breaks. The radiation can ionize DNA in cancer cells, creating strand breaks. DNA double strand breaks (DSB) are harder for the cell to repair than single strand breaks (SSB). The DSB to SSB ratio shows the strength of radiation therapy, indicating damage. It was found that a monochromatic x-ray sent at energy 82 keV produced the highest DNA double strand break to single strand break ratio. This work is part of a novel methodology names Resonant Nanoplasma Theranostics (RNPT) proposed by the OSU group.