scholarly journals DNA Dosimetry with Gold Nanoparticle Irradiated by Proton Beams: A Monte Carlo Study on Dose Enhancement

2021 ◽  
Vol 11 (22) ◽  
pp. 10856
Author(s):  
Ngoc Han Huynh ◽  
James C. L. Chow
Keyword(s):  
Monte Carlo ◽  
Gold Nanoparticle ◽  
Proton Beam ◽  
Beam Energy ◽  
Heavy Atom ◽  
Monte Carlo Study ◽  
Nanoparticle Size ◽  
Proton Radiation ◽  
Dose Enhancement ◽  
Proton Beam Energy

Heavy atom nanoparticles, such as gold nanoparticles, are proven effective radiosensitizers in radiotherapy to enhance the dose delivery for cancer treatment. This study investigated the effectiveness of cancer cell killing, involving gold nanoparticle in proton radiation, by changing the nanoparticle size, proton beam energy, and distance between the nanoparticle and DNA. Monte Carlo (MC) simulation (Geant4-DNA code) was used to determine the dose enhancement in terms of dose enhancement ratio (DER), when a gold nanoparticle is present with the DNA. With varying nanoparticle size (radius = 15–50 nm), distance between the gold nanoparticle and DNA (30–130 nm), as well as proton beam energy (0.5–25 MeV) based on the simulation model, our results showed that the DER value increases with a decrease of distance between the gold nanoparticle and DNA and a decrease of proton beam energy. The maximum DER (1.83) is achieved with a 25 nm-radius gold nanoparticle, irradiated by a 0.5 MeV proton beam and 30 nm away from the DNA.

scholarly journals Estimation of Dose Enhancement for Inhomogeneous Distribution of Nanoparticles: A Monte Carlo Study

2021 ◽  
Vol 11 (11) ◽  
pp. 4900
Author(s):  
Fouad Abolaban ◽  
Eslam Taha ◽  
Abdulsalam Alhawsawi ◽  
Fathi Djouider ◽  
Essam Banoqitah ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Metal Nanoparticles ◽  
Beam Energy ◽  
Positive Impact ◽  
Monte Carlo Study ◽  
Nanoparticle Concentration ◽  
Dose Enhancement ◽  
Hypoxic Conditions ◽  
Innermost Layer ◽  
Necrotic Region

High atomic number nanoparticles are of increasing interest in radiotherapy due to their significant positive impact on the local dose applied to the treatment site. In this work, three types of metal nanoparticles were utilized to investigate their dose enhancement based on the GATE Monte Carlo simulation tool. Gold, gadolinium, and silver were implanted at three different concentrations to a 1 cm radius sphere to mimic a cancerous tumor inside a 10 × 10 × 30 cm3 water phantom. The innermost layer of the tumor represents a necrotic region, where the metal nanoparticles uptake is assumed to be zero, arising from hypoxic conditions. The nanoparticles were defined using the mixture technique, where nanoparticles are added to the chemical composition of the tumor. A directional 2 × 2 cm2 monoenergetic photon beam was used with several energies ranging from 50 keV to 4000 keV. The dose enhancement factor (DEF) was measured for all three metal nanoparticles under all beam energies. The maximum DEF was ~7 for silver nanoparticles with the 50 keV beam energy at the highest nanoparticle concentration of 30 mg/g of water. Gold followed the same trend as it registered the highest DEF at the 50 keV beam energy with the highest concentration of nanoparticles at 30 mg/g, while gadolinium registered the highest at 100 keV.

scholarly journals Ranges of protons in biological targets

2017 ◽  
Vol 68 (4) ◽  
pp. 306-311
Author(s):  
Márius Pavlovič ◽  
Andreas Hammerle
Keyword(s):  
Monte Carlo ◽  
Proton Beam ◽  
Beam Energy ◽  
Data Set ◽  
Target Density ◽  
Biological Targets ◽  
Energy Scaling ◽  
Proton Beam Energy ◽  
Natural Range ◽  
The Mean

AbstractThe paper introduces a simple fitting function for quick assessment of proton ranges in biological targets and human tissues. The function has been found by fitting an extensive data set of Monte Carlo proton ranges obtained with the aid of the SRIM-2013 code. The data has been collected for 28 different targets at 8 energies in the interval from 60 MeV to 220 MeV. The paper shows that at a given kinetic proton-beam energy, the Monte Carlo ranges can be satisfactorily fitted by a power function that depends solely on the target density. This is a great advantage for targets, for which the exact chemical composition is not known, or the mean ionizing potential is not reliably known. The satisfactory fit is meant as the fit that stays within the natural range straggling of the Monte Carlo ranges. In the second step, the energy-scaling yielding a universal fitting formula for proton ranges as a function of proton-beam energy and target density is introduced and discussed.

A detailed experimental and Monte Carlo analysis of gold nanoparticle dose enhancement using 6 MV and 18 MV external beam energies in a macroscopic scale

2021 ◽  
Vol 171 ◽  
pp. 109638
Author(s):  
Tara Gray ◽  
Nema Bassiri ◽  
Shaquan David ◽  
Devanshi Yogeshkumar Patel ◽  
Sotirios Stathakis ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Gold Nanoparticle ◽  
Monte Carlo Analysis ◽  
External Beam ◽  
Macroscopic Scale ◽  
Dose Enhancement

Monte Carlo study on mucosal dose in oral and naval cavity using photon beams with small field

2011 ◽  
Vol 10 (4) ◽  
pp. 261-271 ◽  
Author(s):  
James C.L. Chow ◽  
Amir M. Owrangi
Keyword(s):  
Monte Carlo ◽  
Beam Energy ◽  
Field Size ◽  
Small Field ◽  
Beam Angle ◽  
Photon Beams ◽  
Dose Ratio ◽  
Dose Enhancement ◽  
Bone Interface ◽  
Energy Beam

AbstractWe study how mucosal dose in the oral or nasal cavity depends on the irradiated small segmental photon fields varying with beam energy, beam angle and mucosa thickness. Dose ratio (mucosal dose with bone underneath to dose at the same point without bone) reflecting the dose enhancement due to the bone backscatter was determined by Monte Carlo simulation (EGSnrc-based code), validated by measurements. Phase space files based on the 6 and 18 MV photon beams with small field size of 1 × 1 cm2, produced by a Varian 21 EX linear accelerator, were generated using the BEAMnrc Monte Carlo code. Mucosa phantoms (mucosa thickness = 1, 2 and 3 mm) with and without a bone under the mucosa were irradiated by photon beams with gantry angles varying from 0 to 30°. Doses along the central beam axis in the mucosa and the dose ratio were calculated with different mucosa thicknesses. For the 6 MV photon beams, the dose at the mucosa-bone interface increased by 44.9–41.7%, when the mucosa thickness increased from 1 to 3 mm for the beam angle ranging from 0 to 30°. These values were lower than those (58.8–53.6%) for the 18 MV photon beams with the same beam angle range. For both the 6 and 18 MV photon beams, depth doses in the mucosa were found to increase with an increase of the beam angle. Moreover, the dose gradient in the mucosa was greater for the 18 MV photon beams compared to the 6 MV. For the dose ratio, it was found that the dose enhancement due to the bone backscatter increased with a decrease of mucosa thickness, and was more significant at both the air-mucosa and mucosa-bone interface. Mucosal dose with bone was investigated by Monte Carlo simulations with different experimental configurations, and was found vary with the beam energy, beam angle and mucosa thickness for a small segmental photon field. The dosimetric information in this study should be considered when searching for an optimized treatment strategy to minimize the mucosal complications in the head-and-neck intensity-modulated radiation therapy.

Absolute polarimeter for the proton-beam energy of 200 MeV

2013 ◽  
Vol 76 (12) ◽  
pp. 1490-1496
Author(s):  
A. N. Zelenski ◽  
G. Atoian ◽  
A. A. Bogdanov ◽  
S. B. Nurushev ◽  
F. S. Pylaev ◽  
...  
Keyword(s):  
Proton Beam ◽  
Beam Energy ◽  
Proton Beam Energy
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