Investigation of energy absorption by clustered gold nanoparticles

Kwon, Jihun; Sutherland, Kenneth; Makarova, Anastasia; Matsuura, Tetsuya; Hashimoto, Takayuki; Peng, Hao; Toshito, T.; Umegaki, Kikuo; Shirato, Hiroki; Shimizu, Satoru

doi:10.1016/j.nimb.2018.05.033

Cited by 3 publications

(1 citation statement)

References 61 publications

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“…The effect on the dose enhancement in the cytoplasm amounted to only few percent in the presented simulations. Absorption in gold was found to be more pronounced as a function of GNP diameter and agrees with previously reported increased self-absorption for larger diameters (Kwon et al 2018) and subsequently reduced dose deposition per ionization (Lin et al 2015).…”

Section: Physical Stagesupporting

confidence: 90%

Radio-enhancement by gold nanoparticles and their impact on water radiolysis for x-ray, proton and carbon-ion beams

et al. 2019

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Gold nanoparticle (GNP) radio-enhancement is a promising technique to increase the dose deposition in a tumor while sparing neighboring healthy tissue. Previous experimental studies showed effects on cell survival and tumor control for keV x-rays but surprisingly also for MV-photons, proton and carbon-ion beams. In a systematic study, we use the Monte Carlo simulation tool TOPAS-nBio to model the GNP radio-enhancement within a cell as a function of GNP concentration, size and clustering for a wide range of energies for photons, protons and, for the first time, carbon-ions. Moreover, we include water radiolysis, which has been recognized as a major pathway of GNP mediated radio-enhancement. At a GNP concentration of 0.5% and a GNP diameter of 10 nm, the dose enhancement ratio was highest for 50 keV x-rays (1.36) and decreased in the orthovoltage (1.04 at 250 keV) and megavoltage range (1.01 at 1 MeV). The dose enhancement linearly increased with GNP concentration and decreased with GNP size and degree of clustering for all radiation modalities. While the highest physical dose enhancement at 5% concentrations was only 1.003 for 10 MeV protons and 1.004 for 100 MeV carbon-ions, we find the number of hydroxyl () altered by 23% and 3% after 1 s at low, clinically-relevant concentrations. For the same concentration and proton-impact, the G-value is most sensitive to the nanoparticle size with 46 times more radical interactions at GNPs for 2 nm than for 50 nm GNP diameter within 1 s. Nanoparticle clustering was found to decrease the number of interactions at GNPs, e.g. for a cluster of 25 GNPs by a factor of 3.4. The changes in G-value correlate to the average distance between the chemical species and the GNPs. While the radiochemistry of GNP-loaded water has yet to be fully understood, this work offers a first relative quantification of radiolysis products for a broad parameter-set.

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Section: Physical Stagesupporting

confidence: 90%

Radio-enhancement by gold nanoparticles and their impact on water radiolysis for x-ray, proton and carbon-ion beams

et al. 2019

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Simulation-based correction of dose enhancement factor values in photon brachytherapy with metal nanoparticle targeting

Milutinović

Vujisić

2020

NUCL SCI TECH

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Monte Carlo model for evaluation of concentration of gold nanoparticle clusters as predictor of effective dose in proton therapy of microscopic tumors

Alanazi

Akhdar

et al. 2022

AIP Advances

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Radio-sensitization with gold nanoparticles (GNPs) is a relatively recent advancement of radiotherapy that is determined to increase radiation in the target tumor region. Monte Carlo (MC) simulation is a well-known method that has gained popularity by assisting in determining the effective dose in various tumors. Assessing the concentration of particles during proton therapy can provide the key to evaluating the efficiency of the performed treatment. Therefore, this study aimed to investigate the interconnection between the concentration of gold nanoparticle clusters and the dose enhancement in microscopic tumors by using the MC Model. A single cell tumor model with a size of 5 μm that was exposed to 100 MeV protons in a region resembling the human brain was investigated by using an MC simulation employing the Geant4 toolkit. With each nanoparticle having a diameter of 15 nm, a three-dimensional model of the random distribution of gold nanoparticle clusters was developed. Then, the dose enhancement for various concentrations of the GNPs accumulated around the tumor was estimated according to the dose enhancement factor (DEF), while the dose was concentrated on the surface of each GNP in the clusters. The results showed that the dose enhancement located at the Bragg-peak in the tumor region depended on the different concentrations of the GNPs. DEF values were found to be 1.016, 1.022, 1.026, 1.035, 1.013, 1.000, and 0.984 for the 1, 2, 3, 5, 10, 30, and 50 mg/ml concentration levels in water, respectively. The findings also revealed that large GNP clusters with high concentration levels yield larger DEFs than clusters with lower concentration levels, which may have an impact on radiation therapy. Specifically, at a concentration higher than 10 mg/ml, the estimated dose was significantly lower than those for a concentration of 5 mg/ml by about ∼100 mGy. As the benefit of the increased total dose must be balanced against the effect of the accumulation of nanoparticles, the current study detected dose reduction in regions that accumulate GNPs at high concentrations. As a result, the potential efficiency of the radiotherapeutic treatment can be reduced.

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Investigation of energy absorption by clustered gold nanoparticles

Cited by 3 publications

References 61 publications

Radio-enhancement by gold nanoparticles and their impact on water radiolysis for x-ray, proton and carbon-ion beams

Radio-enhancement by gold nanoparticles and their impact on water radiolysis for x-ray, proton and carbon-ion beams

Simulation-based correction of dose enhancement factor values in photon brachytherapy with metal nanoparticle targeting

Monte Carlo model for evaluation of concentration of gold nanoparticle clusters as predictor of effective dose in proton therapy of microscopic tumors

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