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

Milutinović, Slobodan; Vujisić, Miloš

doi:10.1007/s41365-020-00820-8

Cited by 2 publications

(3 citation statements)

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“…Te decrease is caused by the absorption of secondary electrons in the nanoparticles themselves, an efect referred to as self-absorption. Te increase of nanoparticle concentration in tissue, on the other hand, increases the dose deposited in it, with other parameters kept constant [10,13,31,34]. However, this increase is limited by another absorption efect, referred to in our previous investigation as crossfre, in which secondary electrons emitted by a nanoparticle can get absorbed by its neighbouring NPs-a phenomenon that becomes more prominent as the concentration of nanoparticles rises.…”

Section: Resultsmentioning

confidence: 89%

“…To overcome this, some CH codes apply a "mixed" approach, grouping low-energy transfer collisions into steps, while simulating high-energy transfer collisions (also called "hard" collisions) discretely, based on single-scattering cross sections. Setting the hard collision energy transfer threshold at a particularly low value should, in principle, allow a mixed CH code to simulate all collisions in a discrete way, thus approximating a TS code [31,32].…”

Section: Discussionmentioning

confidence: 99%

“…Nanoscale distributions of deposited energy were obtained by utilizing the Livermore condensed history algorithm for electron transport in Geant4, with parameters of the algorithm adjusted so as to bring it as close as possible to true event-by-event particle tracking (see Appendix A). Te level of detail provided by this physical model allows the nanoparticleladen volume to be modeled as a structured region, with NPs represented as discrete geometrical entities distributed within it, and enables nanodosimetric calculations to be carried out [31]. Physical models chosen for and attuned to nanoscale precision of dose calculations are too complex and demanding for macroscopic calculations and preclude largescale simulations (such as those at tissue level) from being conducted within any reasonable time frame, even with optimized computer resources.…”

Section: Methods and Modelsmentioning

confidence: 99%

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Influence of Gold Nanoparticle Shape and Single-Cell Localization on Energy Deposition Efficiency and Irradiation Specificity in Photon Radiotherapy

Milutinović

Pandurović

Vujisić

2023

Nanomaterials and Nanotechnology

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Gold nanoparticles (AuNPs) have been investigated extensively in the past twenty years as a sensitizing agent in photon radiotherapy. Targeted delivery of AuNPs to specific sites in cells and tissues contributes to highly localized radiation dose enhancement, whereby the surrounding healthy structures can be largely spared from the unwanted radiation effects. The efficiency of introduced AuNPs with regard to dose enhancement depends on the properties of the nanoparticles since not all of deposited radiation energy reaches the intended biological target but is partially absorbed within the nanoparticles themselves or distributed elsewhere. The present paper investigates the influence of AuNP shape and localization on the enhancement and intracellular distribution of deposited energy in radiation therapy with photons. Energy deposition patterns are calculated with nanoscale accuracy through Monte Carlo simulations of radiation transport, which are optimized to accommodate a structured geometrical representation of the region loaded with AuNPs, i.e., to allow discrete modeling of individual nanoparticles. Same-volume nanoparticles of three commonly encountered shapes—nanospheres, nanorods, and square nanoplates—are examined, in order to inspect the differences in the propagation and absorption of secondary charged particles produced by the incident photons. Five different spatial distributions of spherical AuNPs at the single-cell level are studied in the simulations and compared according to the energy deposited in the cell nucleus. Photon energy, nanoparticle size, and concentration are also varied across simulation runs, and their influence is analyzed in connection to nanoparticle shape and localization. The obtained results reveal how the investigated nanoparticle properties affect their dose-enhancing ability and irradiation specificity in AuNP-augmented radiotherapy.

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Section: Resultsmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Methods and Modelsmentioning

confidence: 99%

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Influence of Gold Nanoparticle Shape and Single-Cell Localization on Energy Deposition Efficiency and Irradiation Specificity in Photon Radiotherapy

Milutinović

Pandurović

Vujisić

2023

Nanomaterials and Nanotechnology

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Monte Carlo study of nanoparticles effectiveness on the dose enhancement when irradiated by protons

Ganjeh

Salehi

2023

AIP Advances

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Recently, the nanomedicine field has experienced considerable growth in research. The use of nanoparticles to enhance dose in radiation treatment was proposed and their potential effects can be indicated using Monte Carlo calculations. The main goal of this study focused on nanoparticles’ (NPs) effects on dose enhancement due to the low-energy protons because the majority of studies on NPs have been conducted for photon radiations. To investigate the effect of NPs on the Dose Enhancement Factor (DEF), a cell dimension phantom was modeled and spheres of NPs were localized inside that. Different NPs, such as Au, Pt, Ag, I, and Ta2O3, were located in the phantom, and the DEF was calculated by changing the source energy from 3 to 15 MeV. The purpose of investigating the low-energy proton beam is to clarify the effects around the Bragg peak in the presence of nanoparticles. For protons with an energy range of 3–15 MeV, it was discovered that Pt nanoparticles have a greater dose increase coefficient of about 1.8 times compared to the other nanoparticles. The findings indicated that the DEF values substantially depended on the NPs concentration, but that the DEF was not significantly affected by changes in concentration or nanoparticle size. Comparative calculations between water and soft tissue phantoms that were filled with NPs presented a difference of less than 2%. The obtained findings emphasized the importance of NPs and considered details, such as concentration, to demonstrate the potential of nanoparticles in improving treatment using protons.

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

Cited by 2 publications

References 64 publications

Influence of Gold Nanoparticle Shape and Single-Cell Localization on Energy Deposition Efficiency and Irradiation Specificity in Photon Radiotherapy

Influence of Gold Nanoparticle Shape and Single-Cell Localization on Energy Deposition Efficiency and Irradiation Specificity in Photon Radiotherapy

Monte Carlo study of nanoparticles effectiveness on the dose enhancement when irradiated by protons

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