Monte Carlo study of alternative X-ray sources and K-alpha resonance fluorescence for enhancing radiation therapy

Using the Monte Carlo code GEANT4 we have studied alternative X-ray sources as well as a variety of nanoparticles as a method to improve tumor irradiation and cancer theranostics (therapy and diagnostics). We used GEANT4 to simulate photons from quasi-monochromatic (QX), monochromatic (MX), and traditional broadband (BX) medical X-ray sources interacting with heavy element nanoparticles designed to enhance X-ray absorption [1]. A combined experimental, theoretical, and numerical study of Zr K$_{\alpha,\beta}$ fluorescence and scattering is presented. Simulations of resonant nano-plasma states driven by high-intensity K$_{\alpha}$ radiation is carried out [2], with nanoparticles of gold, platinum, or gadolinium in sizes from 2-20 nm, and shapes including rods, spheres, and cubes. \newline [1] M. S. Westphal et al., Phys. Med. Biol, 62: 6361-6378, 2017. \newline [2] S. N. Nahar and A. K. Pradhan, JQSRT, 155: 32-48, 2015.