Determination of defect depth in industrial radiography imaging using MCNP code and SuperMC software

Khorshidi Abdollah,Khosrowpour Behzad,Hosseini S. Hamed 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.7

Background: Non-destructive evaluation of defects in metals or composites specimens is a regular method in radiographic imaging. The maintenance examination of metallic structures is a relatively difficult effort that requires robust techniques for use in industrial environments. Methods: In this research, iron plate, lead marker and tungsten defect with a 0.1 cm radius in spherical shape were separately simulated by MCNP code and SuperMC software. By 192Ir radiation source, two exposures were considered to determine the depth of the actual defined defect in the software. Also by the code, displacement shift of the defect were computed derived from changing the source location along the x- or y-axis. Results: The computed defect depth was identified 0.71 cm in comparison to the actual one with accuracy of 13%. Meanwhile, the defect position was recognized by disorder and reduction in obtained gamma flux. The flux amount along the x-axis was approximately 0.5Eþ11 units greater than the y-axis. Conclusion: This study provides a method for detecting the depth and position of the defect in a particular sample by combining code and software simulators

Nano Yttrium-90 and Rhenium-188 production through medium medical cyclotron and research reactor for therapeutic usages: A Simulation study

Khorshidi Abdollah 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.5

The main goal of the coordinated project development of therapeutic radiopharmaceuticals of Y-90 and Re-188 is to exploit advancements in radionuclide production technology. Here, direct and indirect production methods with medium reactor and cyclotron are compared to evaluate derived neutron flux and production yield. First, nano-sized 186W and 89Y specimens are suspended in water in a quartz vial by FLUKA simulation. Then, the solution is irradiated for 4 days under 9Eþ14 n/cm2/s neutron flux of reactor. Also, a neutron activator including three layersdlead moderator, graphite reflector, and polyethylene absorbentd is simulated and tungsten target is irradiated by 60 MeV protons of cyclotron to generate induced neutrons for 188W and 90Sr production via neutron capture. As the neutron energy reduced, the flux gradually increased towards epithermal range to satisfy (n/2n,g) reactions. The obtained specific activities at saturation were higher than the reported experimental values because the accumulated epithermal flux and nano-sized specimens influence the outcomes. The beta emitters, which are widely utilized in brachytherapy, appeal an alternative route to locally achieve a rational yield. Therefore, the proposed method via neutron activator may ascertain these broad requirements.

Simulation and assessment of 99mTc absorbed dose into internal organs from cardiac perfusion scan

Salari Saghar,Khorshidi Abdollah,Soltani-Nabipour Jamshid 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.1

Directly, it is not possible to measure the absorbed dose of radiopharmaceuticals in the organs of the human body. Therefore, simulation methods are utilized to estimate the dose in distinct organs. In this study, individual organs were separately considered as the source organ or target organ to calculate the mean absorption dose, which SAF and S factors were then calculated according to the target uptake via MIRD method. Here, 99mTc activity distribution within the target was analyzed using the definition and simulation of ideal organs by summing the fraction of cumulative activities of the heart as source organ. Thus, GATE code was utilized to simulate the Zubal humanoid phantom. To validate the outcomes in comparison to the similar results reported, the accumulation of activity in the main organs of the body was calculated at the moment of injection and cardiac rest condition after 60 min of injection. The results showed the highest dose absorbed into pancreas was about 21%, then gallbladder 18%, kidney 16%, spleen 15%, heart 8%, liver 8%, thyroid 7%, lungs 5% and brain 2%, respectively, after 1 h of injection. This distinct simulation model may also be used for different periods after injection and modifying the prescribed dose

Lung tumor segmentation using improved region growing algorithm

Jamshid Soltani-Nabipour,Abdollah Khorshidi,Behrooz Noorian 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.10

The goal of this project is to achieve an accurate segmentation of the pulmonary tumors besides shortening the time and increasing the accuracy. Here, improved region growing (IRG) algorithm is introduced in order to segment the lung tumor with a sufficient accuracy in a shorter time compared to the other basics methods. This comprehensive algorithm was applied on 4 patients CT images and the results of the various steps on segmentation improvement shown 98% accuracy as compared to the basic algorithm. The combination of “multipoint growth start” produced a desirable outcome in accurately bounding the tumor. The proposed algorithm improved tumor identification by less than 13% along with a sufficient percentage of compliance accuracy.

Robustness of optimized FPID controller against uncertainty and disturbance by fractional nonlinear model for research nuclear reactor

Zare, Nafiseh,Jahanfarnia, Gholamreza,Khorshidi, Abdollah,Soltani, Jamshid Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.9

In this study, a fractional order proportional integral derivative (FOPID) controller is designed to create the reference power trajectory and to conquer the uncertainties and external disturbances. A fractional nonlinear model was utilized to describe the nuclear reactor dynamic behaviour considering thermal-hydraulic effects. The controller parameters were tuned using optimization method in Matlab/Simulink. The FOPID controller was simulated using Matlab/Simulink and the controller performance was evaluated for Hard variation of the reference power and compared with that of integer order a proportional integral derivative (IOPID) controller by two models of fractional neutron point kinetic (FNPK) and classical neutron point kinetic (CNPK). Also, the FOPID controller robustness was appraised against the external disturbance and uncertainties. Simulation results showed that the FOPID controller has the faster response of the control attempt signal and the smaller tracking error with respect to the IOPID in tracking the reference power trajectory. In addition, the results demonstrated the ability of FOPID controller in disturbance rejection and exhibited the good robustness of controller against uncertainty.

Evaluation of dose distribution from 12C ion in radiation therapy by FLUKA code

Jamshid Soltani-Nabipour,Abdollah Khorshidi,Faezeh Shojai,Khazar Khorami 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.10

Heavy ions have a high potential for destroying deep tumors that carry the highest dose at the peak of Bragg. The peak caused by a single-energy carbon beam is too narrow, which requires special measures for improvement. Here, carbon-12 (12C) ion with different energies has been used as a source for calculating the dose distribution in the water phantom, soft tissue and bone by the code of Monte Carlo-based FLUKA code. By increasing the energy of the initial beam, the amount of absorbed dose at Bragg peak in all three targets decreased, but the trend for this reduction was less severe in bone. While the maximum absorbed dose per bone-mass unit in energy of 200 MeV/u was about 30% less than the maximum absorbed dose per unit mass of water or soft tissue, it was merely 2.4% less than soft tissue in 400 MeV/u. The simulation result showed a good agreement with experimental data at GSI Darmstadt facility of biophysics group by 0.15 cm average accuracy in Bragg peak positioning. From 200 to 400 MeV/u incident energy, the Bragg peak location increased about 18 cm in soft tissue. Correspondingly, the bone and soft tissue revealed a reduction dose ratio by 2.9 and 1.9. Induced neutrons did not contribute more than 1.8% to the total energy deposited in the water phantom. Also during 12C ion bombardment, secondary fragments showed 76% and 24% of primary 200 and 400 MeV/u, respectively, were present at the Bragg-peak position. The combined treatment of carbon ions with neutron or electron beams may be more effective in local dose delivery and also treating malignant tumors.

Silver Sulfadiazine-loaded PVA/CMC Nanofibers for the Treatment of Wounds Caused by Excision

Reza Alipour,Alireza Khorshidi,Abdollah Fallah Shojaei,Farhad Mashayekhi,Mohammad Javad Mehdipour Moghaddam 한국섬유공학회 2019 Fibers and polymers Vol.20 No.12

Polyvinyl alcohol/carboxymethylcellulose/silver sulfadiazine composite nanofibers (PVA/CMC/SSD) containingdifferent proportions of each ingredient were prepared by electrospinning and characterized by Fourier-transform infraredspectroscopy (FTIR), scanning electron microscopy (SEM), thermo-gravimetric analysis (TGA), powder X-ray diffractionanalysis (XRD), atomic absorption spectroscopy (AAS), and ultraviolet-visible (UV-Vis) spectroscopy. The obtainednanofibers were uni-axially formed with randomly oriented longitudinal axes without entanglement, and their meandiameters ranged from 160 to 210 nm. Silver sulfadiazine, on the other hand, was appeared as a non-uniform dispersion ofspherical nanoparticles ranging from 35 to 75 nm over the surface of nanofibers. Efficacy of the silver sulfadiazine loadednanofibers for treatment of wounds caused be excision in rabbits in a period of 14 days was evaluated and it was found thatthe extent of skin repair in the applied dressing depends on the total Ag content. The dressing composed of 73.6:24.6:1.8weight percent of PVA/CMC/SSD provided the best result in comparison with a control dressing made form PVA/CMC(88.8:11.2 %). In vitro cell viability of fibers on HSF-PI 18 fibroblast like cells was assessed by MTT assay. Antibacterialactivity of the prepared nanofibers was also evaluated against gram-negative Escherichia coli and Pseudomonas aeroginosa,and gram-positive Staphylococcus aureus. PVA/CMC/SSD samples, was shown to have significant inhibition effect incomparison with drug references including penicillin G, chloramphenicol and erythromycin as positive controls (P<0.05).