A Monte Carlo investigation of some important radiation parameters and tissue equivalency for photons below 1 keV in human tissues

2021 ◽  
Author(s):  
Mustafa Mohammad Rafiei ◽  
Sara Parsaei ◽  
Parminder Kaur ◽  
Kanwar J Singh ◽  
Mehmet Büyükyıldız ◽  
...  
Keyword(s):  
Atomic Number ◽  
Gamma Ray ◽  
Effective Atomic Number ◽  
Mean Free Path ◽  
Relative Difference ◽  
Eye Lens ◽  
Equivalent Material ◽  
Human Tissues ◽  
Attenuation Coefficients ◽  
Tissue Equivalent

Abstract The attenuation coefficients are important input values in estimating not only the dose and exposure in radiotherapy and medical imaging, but also in the proper design of photon shields. While studies are widely available above 1 keV, the attenuation coefficients of human tissues for photon energies less than 1 keV have not been studied yet. In this study, the attenuation coefficients of water and some human tissues were estimated for low energy photons using the MCNP6.1 code in the energy region 0.1 keV-1 keV. Mass attenuation coefficients were estimated at photon energies of 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950 and 1000 eV for water and ten human tissues (Soft, Breast, Lung, Bone, Brain, Eye lens, Ovary, Skin, Thyroid and Prostate). Results were compared with those available in literature and a fairly good agreement has been obtained. These data were then used to calculate the mean free path, half value layer, tenth value layer, effective atomic number and specific gamma-ray constant (useful for calculation of dose rate) as well. Moreover, for comparison the effective atomic number of the water has been obtained using the results of this work and using the data available in NIST database from 0.1 to 1 keV. In addition, the human tissues were compared with some tissue equivalent materials in terms of effective atomic number and specific gamma-ray constant to study the tissue equivalency from the results, the muscle-equivalent liquid with sucrose has been found to be the best tissue equivalent material for soft tissue, eye lens and brain with relative difference below 4.1%.

scholarly journals Detailed Inspection of γ-ray, Fast and Thermal Neutrons Shielding Competence of Calcium Oxide or Strontium Oxide Comprising Bismuth Borate Glasses

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2265
Author(s):  
Gandham Lakshminarayana ◽  
Youssef Elmahroug ◽  
Ashok Kumar ◽  
Huseyin Ozan Tekin ◽  
Najeh Rekik ◽  
...  
Keyword(s):  
Atomic Number ◽  
Effective Atomic Number ◽  
Mean Free Path ◽  
Intermediate Energy ◽  
Fast Neutrons ◽  
Attenuation Coefficients ◽  
Neutron Attenuation ◽  
Removal Cross Section ◽  
Γ Ray ◽  
Buildup Factors

For both the B2O3-Bi2O3-CaO and B2O3-Bi2O3-SrO glass systems, γ-ray and neutron attenuation qualities were evaluated. Utilizing the Phy-X/PSD program, within the 0.015–15 MeV energy range, linear attenuation coefficients (µ) and mass attenuation coefficients (μ/ρ) were calculated, and the attained μ/ρ quantities match well with respective simulation results computed by MCNPX, Geant4, and Penelope codes. Instead of B2O3/CaO or B2O3/SrO, the Bi2O3 addition causes improved γ-ray shielding competence, i.e., rise in effective atomic number (Zeff) and a fall in half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP). Exposure buildup factors (EBFs) and energy absorption buildup factors (EABFs) were derived using a geometric progression (G–P) fitting approach at 1–40 mfp penetration depths (PDs), within the 0.015–15 MeV range. Computed radiation protection efficiency (RPE) values confirm their excellent capacity for lower energy photons shielding. Comparably greater density (7.59 g/cm3), larger μ, μ/ρ, Zeff, equivalent atomic number (Zeq), and RPE, with the lowest HVL, TVL, MFP, EBFs, and EABFs derived for 30B2O3-60Bi2O3-10SrO (mol%) glass suggest it as an excellent γ-ray attenuator. Additionally, 30B2O3-60Bi2O3-10SrO (mol%) glass holds a commensurably bigger macroscopic removal cross-section for fast neutrons (ΣR) (=0.1199 cm−1), obtained by applying Phy-X/PSD for fast neutrons shielding, owing to the presence of larger wt% of ‘Bi’ (80.6813 wt%) and moderate ‘B’ (2.0869 wt%) elements in it. 70B2O3-5Bi2O3-25CaO (mol%) sample (B: 17.5887 wt%, Bi: 24.2855 wt%, Ca: 11.6436 wt%, and O: 46.4821 wt%) shows high potentiality for thermal or slow neutrons and intermediate energy neutrons capture or absorption due to comprised high wt% of ‘B’ element in it.

scholarly journals A Systematical Characterization of TeO2–V2O5 Glass System Using Boron (III) Oxide and Neodymium (III) Oxide Substitution: Resistance Behaviors against Ionizing Radiation

2021 ◽  
Vol 11 (7) ◽  
pp. 3035
Author(s):  
H. O. Tekin ◽  
Shams A. M. Issa ◽  
G. Kilic ◽  
Hesham M. H. Zakaly ◽  
N. Tarhan ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Effective Atomic Number ◽  
Mean Free Path ◽  
Radiation Shielding ◽  
Glass System ◽  
Buildup Factor ◽  
Attenuation Coefficients ◽  
Gamma Ray Attenuation ◽  
Buildup Factors

This study aimed to perform an extensive characterization of a 74.75TeO2–0.25V2O5–(25 − x)B2O3-xNd2O3 glass system with (x = 0, 0.5, 1.0, and 1.5 mol%) for radiation shielding properties. Linear and mass attenuation coefficients were determined using Phy-X PSD software and compared with the simulation using Monte Carlo software MCNPX (version 2.7.0). Half value layer, mean free path, tenth value layer, effective atomic number, exposure buildup factor, and energy absorption buildup factors of VTBNd0.0, VTBNd0.5, VTBNd1.0, and VTBNd1.5 glasses were determined, respectively. The results showed that boron (III) oxide and neodymium (III) oxide substitution has an obvious impact on the gamma ray attenuation properties of the studied glasses. It can be concluded that the VTBNd1.5 sample with the highest content of neodymium (III) oxide (1.5 mol%) is the superior sample for shielding of gamma radiation in the investigated energy range.

Calculate Effective Atomic Number, Mass and Cross-Section Attenuation Coefficients for Nonanoic Acid by Using Gamma-Ray Sources

2021 ◽  
Vol 19 (11) ◽  
pp. 15-21
Author(s):  
Ali Adil Turki Aldalawi ◽  
Mohammed Yahya Hadi ◽  
Rawaa A. Hameed
Keyword(s):  
Attenuation Coefficient ◽  
Cross Section ◽  
Atomic Number ◽  
Gamma Ray ◽  
Effective Atomic Number ◽  
Mass Attenuation Coefficient ◽  
Nonanoic Acid ◽  
Attenuation Coefficients ◽  
Effective Electron ◽  
Mass Attenuation

The effective atomic number (Z effective), total atomic cross-section (б Total) electron density (N effective) have been Measured depending on the mass attenuation coefficient (μ/ρ). By using Gamma-ray radiation (γ), emitted from sources (57𝐶𝑜, 133𝐵𝑎, 22𝑁𝑎, 137𝐶𝑠, 54𝑀𝑛, 𝑎𝑛𝑑 60𝐶𝑜) with energies from (0.122, 0.356, 0.511, 0.662, 0.84, 1.17, 1.275 𝑎𝑛𝑑 1.33𝑀𝑒𝑉) respectively. using the Sodium Iodide Scintillation Detectors NaI (Tl) at 662 keV and resolution about 8.2% have been measured the mass attenuation coefficients for the sample “Nonanoic acid its common name Pelargonic acid” it’s chemical formula C9H18O2. The data from the mass attenuation coefficient were then employed to study Zeffective, Neffective, and бtotal of the sample. In the presence of gamma-ray energy, it was discovered that the effective atomic number and effective electron densities first drop and they tend to remain nearly constant. The experimental values obtained by Zeffective and Neffective were in excellent agreement with the theoretical values. The theoretical data that is accessible is obtained from XCom, which is available online. The study's findings aid in understanding how (μ/ρ) values change when Zeff and Neff values vary in the case of H, C, and O based biological molecules such as fatty acids.

Electron Density and Effective Atomic Number Measurement by Using a Newly Developing Photon Counting CT System

2020 ◽  
Vol 38 ◽  
pp. 93-99
Author(s):  
Hiroshi Sakurai ◽  
Kazushi Hoshi ◽  
Yosuke Harasawa ◽  
Daiki Ono ◽  
Kun Zhang ◽  
...  
Keyword(s):  
Electron Density ◽  
Atomic Number ◽  
Photon Counting ◽  
Effective Atomic Number ◽  
Image Data ◽  
Detector Response ◽  
Simple Method ◽  
Attenuation Coefficients ◽  
X Ray ◽  
Ct System

We developed the photon counting CT system by using a conventional laboratory X-ray source and a CdTe line sensor. Attenuation coefficients were obtained from the measured CT image data. Our suggested method for deriving the electron density and effective atomic number from the measured attenuation coefficients was tested experimentally. The accuracy of the electron densities and effective atomic numbers are about <5 % (the averages of absolute values are 2.6 % and 3.1 %, respectively) for material of 6< Z and Zeff <13. Our suggested simple method, in which we do not need the exact source X-ray spectrum and detector response function, achieves comparable accuracy to the previous reports.

scholarly journals Enhancement of Bentonite Materials with Cement for Gamma-Ray Shielding Capability

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4697
Author(s):  
Ahmed M. El-Khatib ◽  
Mohamed Elsafi ◽  
Mohamed N. Almutiri ◽  
R. M. M. Mahmoud ◽  
Jamila S. Alzahrani ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Mean Free Path ◽  
Radiation Shielding ◽  
Point Sources ◽  
Linear Attenuation Coefficient ◽  
Buildup Factor ◽  
Chemical Compositions ◽  
Attenuation Coefficients ◽  
Water Holding ◽  
Mixed Samples

The gamma-ray shielding ability of various Bentonite–Cement mixed materials from northeast Egypt have been examined by determining their theoretical and experimental mass attenuation coefficients, μm (cm2g−1), at photon energies of 59.6, 121.78, 344.28, 661.66, 964.13, 1173.23, 1332.5 and 1408.01 keV emitted from 241Am, 137Cs, 152Eu and 60Co point sources. The μm was theoretically calculated using the chemical compositions obtained by Energy Dispersive X-ray Analysis (EDX), while a NaI (Tl) scintillation detector was used to experimentally determine the μm (cm2g−1) of the mixed samples. The theoretical values are in acceptable agreement with the experimental calculations of the XCom software. The linear attenuation coefficient (μ), mean free path (MFP), half-value layer (HVL) and the exposure buildup factor (EBF) were also calculated by knowing the μm values of the examined samples. The gamma-radiation shielding ability of the selected Bentonite–Cement mixed samples have been studied against other puplished shielding materials. Knowledge of various factors such as thermo-chemical stability, availability and water holding capacity of the bentonite–cement mixed samples can be analyzed to determine the effectiveness of the materials to shield gamma rays.

scholarly journals Experimental Investigation of Radiation Shielding Competence of Bi2O3-CaO-K2O-Na2O-P2O5 Glass Systems

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5061
Author(s):  
Dalal Abdullah Aloraini ◽  
Aljawhara H. Almuqrin ◽  
M. I. Sayyed ◽  
Hanan Al-Ghamdi ◽  
Ashok Kumar ◽  
...  
Keyword(s):  
Attenuation Coefficient ◽  
Gamma Ray ◽  
Effective Atomic Number ◽  
Mass Attenuation Coefficient ◽  
Radiation Shielding ◽  
The Other ◽  
Linear Attenuation Coefficient ◽  
Attenuation Coefficients ◽  
Positive Effect ◽  
Theoretical Results

The gamma-ray shielding features of Bi2O3-CaO-K2O-Na2O-P2O5 glass systems were experimentally reported. The mass attenuation coefficient (MAC) for the fabricated glasses was experimentally measured at seven energy values (between 0.0595 and 1.33 MeV). The compatibility between the practical and theoretical results shows the accuracy of the results obtained in the laboratory for determining the MAC of the prepared samples. The mass and linear attenuation coefficients (MACs) increase with the addition of Bi2O3 and A4 glass possesses the highest MAC and LAC. A downward trend in the linear attenuation coefficient (LAC) with increasing the energy from 0.0595 to 1.33 MeV is found. The highest LAC is found at 1.33 MeV (in the range of 0.092–0.143 cm−1). The effective atomic number (Zeff) follows the order B1 > A1 > A2 > A3 > A4. This order emphasizes that increasing the content of Bi2O3 has a positive effect on the photon shielding proficiencies owing to the higher density of Bi2O3 compared with Na2O. The half value layer (HVL) is also determined and the HVL for the tested glasses is computed between 0.106 and 0.958 cm at 0.0595 MeV. The glass with 10 mol% of Bi2O3 has lower HVL than the glasses with 0, 2.5, 5, and 7.5 mol% of Bi2O3. So, the A4 glass needs a smaller thickness than the other glasses to shield the same radiation. As a result of the reported shielding parameters, inserting B2O3 provides lower values of these three parameters, which in turn leads to the development of superior photons shields.

scholarly journals Gamma-Ray Attenuation and Exposure Buildup Factor of Novel Polymers in Shielding Using Geant4 Simulation

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5051
Author(s):  
Mahmoud T. Alabsy ◽  
Jamila S. Alzahrani ◽  
M. I. Sayyed ◽  
Mahmoud I. Abbas ◽  
Daria I. Tishkevich ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Effective Atomic Number ◽  
Buildup Factor ◽  
Geant4 Simulation ◽  
Polybutylene Terephthalate ◽  
Attenuation Coefficients ◽  
High Energies ◽  
Gamma Ray Attenuation ◽  
Mass Attenuation Coefficients ◽  
Good Agreement

Polymers are often used in medical applications, therefore, some novel polymers and their interactions with photons have been studied. The gamma-ray shielding parameters for Polymethylpentene (PMP), Polybutylene terephthalate (PBT), Polyoxymethylene (POM), Polyvinylidenefluoride (PVDF), and Polychlorotrifluoroethylene (PCTFE) polymers were determined using the Geant4 simulation and discussed in the current work. The mass attenuation coefficients (μ/ρ) were simulated at low and high energies between 0.059 and 1.408 MeV using different radionuclides. The accuracy of the Geant4 simulated results were checked with the XCOM software. The two different methods had good agreement with each other. Exposure buildup factor (EBF) was calculated and discussed in terms of polymers under study and photon energy. Effective atomic number (Zeff) and electron density (Neff) were calculated and analyzed at different energies. Additionally, the half-value layer (HVL) of the polymers was evaluated, and the results of this parameter showed that PCTFE had the highest probability of interaction with gamma photons compared to those of the other tested polymers.

scholarly journals New Intrinsic Scintillator with Large Effective Atomic Number: Tl2HfCl6 and Tl2ZrCl6 Crystals for X-ray and Gamma-ray Detections

2018 ◽  
Vol 30 (7) ◽  
pp. 1577 ◽  
Author(s):  
Yutaka Fujimoto ◽  
Keiichiro Saeki ◽  
Daisuke Nakauchi ◽  
Takayuki Yanagida ◽  
Masanori Koshimizu ◽  
...  
Keyword(s):  
Atomic Number ◽  
Gamma Ray ◽  
Effective Atomic Number ◽  
X Ray
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