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1.
Appl Radiat Isot ; 208: 111296, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38508065

RESUMO

This study aimed to investigate the effect of diabetes on radiation attenuation parameters of the femur and tibia of rats using Monte Carlo Simulations. First, control and diabetic rats were identified and tibias and femurs were removed. Then, the elemental ratios of the bones obtained were calculated using EDS (Energy Dissipative X-ray Spectroscopy). Therefore, radiation permeability properties of control and diabetic bones were simulated by using the content ratios in the bones in MCNP6 (Monte Carlo N-Particle) and PHITS (Particle and Heavy Ion Transport code System) 3.22 and Stopping and Range of Ions in Matter (SRIM) simulation codes. Attenuation coefficient results were compared with the NIST database via XCOM. Although differences in absorption coefficients are observed at low energies, these differences disappear as the energy increases.


Assuntos
Diabetes Mellitus Experimental , Tíbia , Ratos , Animais , Tíbia/diagnóstico por imagem , Projetos Piloto , Simulação por Computador , Fêmur/diagnóstico por imagem , Método de Monte Carlo
2.
Appl Radiat Isot ; 191: 110553, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36401990

RESUMO

Fluorodeoxyglucose (FDG), marked with the most used Positron Emission Tomography (PET) radiopharmaceutical Fluorine-18 (F-18), is a glucose analog and is taken to living cells through membrane glucose carriers. F-18 FDG involvement in tissue is proportional to glucose use. In many cancers, there is increased glucose use due to increased gluten expression and hexokinase activity. F-18 FDG PET is a proven method for diagnosis, staging, re-staging, and evaluation of treatment response in oncology. The purpose of this study is to find the effect of ionizing radiation on proteins in the mechanism of action of FDG and determine to Molecular mechanisms of F-18 FDG accumulation in metabolism. In the study, two different models were used together, the first method, the study was Molecular Docking method for modeling molecules deconstructed and the structure of FDG was energy minimized by utilizing the density functional theory, and the B3LYP functional was used with 6-311G basis set. The second method was the Monte Carlo method for modeling ionizing radiation interactive with the potential routes of FDG metabolism within the cell. It was determined that the Gibbs free energy (ΔG) change was compatible with the ionizing radiation factors for binding of FDG to the aphthous regions of Glucose-6-phosphate isomerase (G1), hexokinase (G2), and glucose transporter-1 (G3) were selected. In this study, the strong binding of FDG to protein influences the effect of radiation on the active site of enzymes. The G1 and G3 shown in the study interacted with only one charged amino acid FDG, and the absence of an aromatic residue around it can be considered among the results of this study as the cause of the low protective effect against ionizing radiation.


Assuntos
Fluordesoxiglucose F18 , Compostos Radiofarmacêuticos , Simulação de Acoplamento Molecular , Hexoquinase , Glucose
3.
Appl Radiat Isot ; 188: 110364, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35839712

RESUMO

Monte Carlo simulation method and Nuclear Medicine MIRD method were used to evaluate the effect of radiopharmaceuticals on Covid-19 disease. The mean absorbed organ dose in the target organ and gamma radiation emitter attenuation properties such as linear attenuation coefficients, energy absorption build-up factors (EABF), exposure build-up factors (EBF), and relative dose distributions (RDD) were examined. The results showed that radiopharmaceuticals containing gamma radiation emitters which are densely ionizing charged particles induced membrane damage and produced protein damage.


Assuntos
COVID-19 , Compostos Radiofarmacêuticos , Simulação por Computador , Humanos , Método de Monte Carlo , Radiometria/métodos , Compostos Radiofarmacêuticos/uso terapêutico
4.
Mater Chem Phys ; 260: 124093, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33262549

RESUMO

This article explores the effectiveness of gamma rays attenuation of various N95 respirator samples by analysing several theoretical parameters such as the Effective Atomic Numbers (Zeff), Half Value Layer (HVL), Mean Free Path (MFP), Mass Attenuation Coefficients (MAC), Tenth Value Layer (TVL), Exposure Build Up Factors (EBF) and Energy Absorption Build Up Factors (EABF). For the selected N95 mask samples, the MAC values corresponding to the energy levels between 0.015 and 20 MeV are measured using the WinXCOM software and the MATLAB code. The parameters including Zeff, TVL, HVL, and MFP are computed using the MAC values derived from the WinXCOM program. EBF and EABF are computed in relation to the penetration depth and incident photon energy by using the (G-P) fitting approximation in estimating the photon build-up factor. The findings showed that having the lowest TVL, HVL, and MFP, the N2 sample has the best output in terms of radiation attenuation purposes. In conclusion, the N2 sample which outperforms other samples is the most promising mask sample when it comes to gamma-ray attenuation features.

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