TY - GEN
T1 - Study of dose enhancement effects in the vicinity of high Z atoms with Geant4 Monte Carlo simulation
AU - Huang, Ke
AU - Yan, Kaiguo
AU - Yu, Yan
PY - 2010
Y1 - 2010
N2 - Dose enhancements in the vicinity of different high Z (HZ) materials in radiation therapy (RT) are studied by several groups. In this work, extensive and systematic Monte Carlo (MC) studies were performed with Geant4 toolkit focusing on factors that influence the dose enhancements, including the atomic number of HZ materials, the concentration of the HZ material, and the X-ray energies. Gold (Au), Platinum (Pt), Gadolinium (Gd), and Iodine (I) are used in the study. A new method has been implemented to determine the individual contributions from pair production, Compton scattering and the photoelectric effect to the total dose. The dose enhancement ratios (DERs) and their contributions to the overall dose deposition are calculated for these processes. It is also shown in the study that with fixed X-ray energy and molar concentration, the DERs for these HZ materials are approximately linear proportional to their Z number. The DER increases linearly with HZ concentration; however, the slope of the increase depends on the X-ray energies. Analysis of the DERs from different processes reveals an interesting phenomenon: although the contribution from the photoelectric effect to the overall dose enhancement for X-rays in the MeV range is low, being normally less than 3%, the DER for the photoelectric effect from MeV X-rays are higher than that from X-rays in keV range.
AB - Dose enhancements in the vicinity of different high Z (HZ) materials in radiation therapy (RT) are studied by several groups. In this work, extensive and systematic Monte Carlo (MC) studies were performed with Geant4 toolkit focusing on factors that influence the dose enhancements, including the atomic number of HZ materials, the concentration of the HZ material, and the X-ray energies. Gold (Au), Platinum (Pt), Gadolinium (Gd), and Iodine (I) are used in the study. A new method has been implemented to determine the individual contributions from pair production, Compton scattering and the photoelectric effect to the total dose. The dose enhancement ratios (DERs) and their contributions to the overall dose deposition are calculated for these processes. It is also shown in the study that with fixed X-ray energy and molar concentration, the DERs for these HZ materials are approximately linear proportional to their Z number. The DER increases linearly with HZ concentration; however, the slope of the increase depends on the X-ray energies. Analysis of the DERs from different processes reveals an interesting phenomenon: although the contribution from the photoelectric effect to the overall dose enhancement for X-rays in the MeV range is low, being normally less than 3%, the DER for the photoelectric effect from MeV X-rays are higher than that from X-rays in keV range.
KW - Contribution from processes
KW - Dose enhancement
KW - Gold
KW - High Z
KW - Radiation therapy
KW - X-rays
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U2 - 10.1109/BMEI.2010.5639270
DO - 10.1109/BMEI.2010.5639270
M3 - Conference contribution
AN - SCOPUS:78650669888
SN - 9781424464968
T3 - Proceedings - 2010 3rd International Conference on Biomedical Engineering and Informatics, BMEI 2010
SP - 1260
EP - 1264
BT - Proceedings - 2010 3rd International Conference on Biomedical Engineering and Informatics, BMEI 2010
T2 - 3rd International Conference on BioMedical Engineering and Informatics, BMEI 2010
Y2 - 16 October 2010 through 18 October 2010
ER -