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MO‐FG‐BRA‐03: A Monte‐Carlo Study of Cellular Dosimetry of Radioactive Gold‐Palladium Nanoparticles
Author(s) -
Ma Y,
Michaud F,
Fortin M,
Beaulieu L
Publication year - 2015
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4925407
Subject(s) - palladium , colloidal gold , auger effect , dosimetry , nucleus , materials science , radiochemistry , nanoparticle , atomic physics , analytical chemistry (journal) , nanotechnology , auger , chemistry , physics , nuclear medicine , medicine , biochemistry , chromatography , microbiology and biotechnology , biology , catalysis
Purpose: Radioactive gold‐palladium nanoparticles ( 1 ⁰ 3 Pd:Pd@Au NPs) are being developed for prostate cancer brachytherapy. Photons emitted by the radioisotope palladium (photon energy: 20.1 and 23.0 keV), interacting with gold‐coating of NPs, lead to enhanced energy distribution in nucleus. Here, a simple cellular model was studied using detailed track‐structure method. Methods: Geant4‐DNA was used with auger electrons enabled. Biological cell was modeled as a sphere of radius r=5 µm that were immersed in a fluid containing large number of NPs at different concentrations (S=1, 2.15, 5.1, 17.2 mg‐Au/g‐H2O). Nucleus was modeled as a concentric sphere (r=3µm). Thickness of gold‐coating on 1 ⁰ 3 Pd core was 15nm, 20nm and 25nm, respectively. A scenario of NP diffusion was investigated, where S=5.1 mg‐Au/g‐H2O outside cell and S=1 mg‐Au/g‐H2O in cytoplasm. 10 1 ⁰ 1 ⁰ 3 Pd decays were simulated for each combination of NP concentration and gold‐coating. Results: A uniform increase in energy deposition (Edep) is observed in cell nucleus and the energy enhancement ratio (EER) is 1.16, 1.22 and 1.3 for 15nm, 20nm and 25nm of gold ‐coatings, respectively. Edep at the center of nucleus is increased by a factor of 1.47, 2.51 and 5.54 when the NP concentration in the cytoplasm increases from 1 mg‐Au/g‐H2O to 2.15, 5.10 and 17.2 mg‐Au/g‐H2O, respectively. When NPs diffuse into cytoplasm, the mean value of Edep in nucleus increases from 0.42 to 1.13 MeV per 10⁹ decays (GBq‐Second) of 1 ⁰ 3 Pd and the maximum value increases from 0.54 to 2.5 MeV per GBq‐Second. Conclusion: These results suggest that 1 ⁰ 3 Pd:Pd@Au NPs constitute a promising nanotherapeutic agent. Ongoing studies use transmission electron microscopy (TEM) images of prostate cancer.