TY - JOUR
T1 - Monte carlo simulations and atomic calculations for auger processes in biomedical nanotheranostics
AU - Montenegro, Maximiliano
AU - Nahar, Sultana N.
AU - Pradhan, Anil K.
AU - Huang, Ke
AU - Yu, Yan
PY - 2009/11/12
Y1 - 2009/11/12
N2 - We present numerical simulations of X-ray emission and absorption in a biological environment for which we have modified the general-purpose computer code Geant4. The underlying mechanism rests on the use of heavy nanoparticles delivered to specific sites, such as cancerous tumors, and treated with monoenergetic X-rays at resonant atomic and molecular transitions. X-ray irradiation of high-Z atoms results in Auger decays of photon emission and electron ejections creating multiple electron vacancies. These vacancies may be filled either be radiative decays from higher electronic shells or by excitations from the K-shell at resonant energies by an external X-ray source, as described in an accompanying paper by Pradhan et al. in this volume. Our Monte Carlo models assume normal body material embedded with a layer of gold nanoparticles. The simulation results presented in this paper demonstrate that resonant excitations via Kα, Kβ, etc., transitions result in a considerable enhancement in localized X-ray energy deposition at the layer with gold nanoparticles, compared with nonresonant processes and energies. The present results could be applicable to in vivo therapy and diagnostics (theranostics) of cancerous tumors using high-Z nanoparticles and monochromatic X-ray sources according to the resonant theranostics (RT) methodology.
AB - We present numerical simulations of X-ray emission and absorption in a biological environment for which we have modified the general-purpose computer code Geant4. The underlying mechanism rests on the use of heavy nanoparticles delivered to specific sites, such as cancerous tumors, and treated with monoenergetic X-rays at resonant atomic and molecular transitions. X-ray irradiation of high-Z atoms results in Auger decays of photon emission and electron ejections creating multiple electron vacancies. These vacancies may be filled either be radiative decays from higher electronic shells or by excitations from the K-shell at resonant energies by an external X-ray source, as described in an accompanying paper by Pradhan et al. in this volume. Our Monte Carlo models assume normal body material embedded with a layer of gold nanoparticles. The simulation results presented in this paper demonstrate that resonant excitations via Kα, Kβ, etc., transitions result in a considerable enhancement in localized X-ray energy deposition at the layer with gold nanoparticles, compared with nonresonant processes and energies. The present results could be applicable to in vivo therapy and diagnostics (theranostics) of cancerous tumors using high-Z nanoparticles and monochromatic X-ray sources according to the resonant theranostics (RT) methodology.
UR - http://www.scopus.com/inward/record.url?scp=70449413830&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=70449413830&partnerID=8YFLogxK
U2 - 10.1021/jp905323y
DO - 10.1021/jp905323y
M3 - Article
C2 - 19711928
AN - SCOPUS:70449413830
SN - 1089-5639
VL - 113
SP - 12364
EP - 12369
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 45
ER -