Monte Carlo Method
Ali Azizi Ganjgah; Payvand Taherparvar
Abstract
Radiation therapy aims to maximize doses to cancer cells while minimizing damage to normal tissues. Today, nanoparticles containing high-atomic-number elements, such as gold, gadolinium, and silver, have proven effective as radiosensitizers in radiotherapy to enhance dose delivery for cancer treatment. ...
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Radiation therapy aims to maximize doses to cancer cells while minimizing damage to normal tissues. Today, nanoparticles containing high-atomic-number elements, such as gold, gadolinium, and silver, have proven effective as radiosensitizers in radiotherapy to enhance dose delivery for cancer treatment. In this study, we used the Geant4-DNA toolkit to investigate the effects of multiple nanoparticles (NPs) with varying sizes (radius= 3.15 to 5 nm) on DNA damage when exposed to monoenergetic photons with energies of 15, 40, 50, and 68 keV. Direct and indirect single-strand breaks (SSBs), double-strand breaks (DSBs), and hybrid double-strand breaks (Hybrid DSBs) were calculated in the presence and absence of 1 to 4 nanoparticles (NPs) of the same total volume of gold, gadolinium, and silver nanoparticles for the 1ZBB model (selected from the Protein Data Bank (PDB) library). The results show that increasing the number of gold, gadolinium, and silver NPs and decreasing the photon beam energy increases the total number of strand breaks. Furthermore, gold nanoparticles (GNPs) are more effective options than gadolinium nanoparticles (GdNPs), and silver nanoparticles (SNPs) for inhibiting and controlling cancer cells.
Payvand Taherparvar; Ali AziziGanjgah
Abstract
Low energy I-125- seeds are considered as a common source in different brachytherapy techniques for treatment of different cancers. In this study, at first, we simulated and validated I-125 (model 6711) seed according to the TG-43U1 recommendation, by GEANT4 Monte Carlo toolkit. Moreover, we simulated ...
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Low energy I-125- seeds are considered as a common source in different brachytherapy techniques for treatment of different cancers. In this study, at first, we simulated and validated I-125 (model 6711) seed according to the TG-43U1 recommendation, by GEANT4 Monte Carlo toolkit. Moreover, we simulated new seeds containing cylindrical Ag+Al2O3 markers with different ratio of Ag and Al2O3 in the final composition of the marker and compared the radial dose functions and anisotropy functions of the sources. For validation and evaluation purposes, the radial dose function and anisotropy function were calculated at various distances from the center of the different simulated sources. The source validation results show that GEANT4 Monte Carlo toolkit produces accurate results for dosimetric parameters of the I-125 seed by choosing the appropriate physics list. On the other hand, results show a similarity between calculated dosimetric parameters of the I-125 seed (6711) and other sources, with a percentage difference of about 5%.