Huseyin Ozan Tekin

Effects of micro-sized and nano-sized WO3 on mass attenauation coefficients of concrete by using MCNPX code

In the present work the effect of tungsten oxide (WO3) nanoparticles on mass attenauation coefficients of concrete has been investigated by using MCNPX (version 2.4.0). The validation of generated MCNPX simulation geometry has been provided by comparing the results with standard XCOM data for mass attenuation coefficients of concrete. A very good agreement between XCOM and MCNPX have been obtained. The validated geometry has been used for definition of nano-WO3 and micro-WO3 into concrete sample. The mass attenuation coefficients of pure concrete and WO3 added concrete with micro-sized and nano-sized have been compared. It was observed that shielding properties of concrete doped with WO3 increased. The results of mass attenauation coefficients also showed that the concrete doped with nano-WO3 significanlty improve shielding properties than micro-WO3. It can be concluded that addition of nano-sized particles can be considered as another mechanism to reduce radiation dose.

Monte Carlo Simulation for Distance and Absorbed Dose Calculations in a PET-CT Facility by Using MCNP-X

Modern PET/CT clinics consist of a scanner room housing the double gantry PET/CT unit and a control area. These areas should be considered as a parts of facility that must be protected. The scanner room, quiet rooms, and frequently the hot lab require structural shielding to protect staff and personnel in surrounding areas. The 511 keV photons from the PET positron emitting isotopes are the source term for the quiet rooms and the hot lab, while both the 511 keV photons and the multi-energetic spectrum of x-rays from the CT unit must be considered for the scanner room. In this study, we have developed a 3D (three dimensional) model of PET-CT scanner room by using MCNP-X (version 2.4.0) Monte Carlo code. We considered the distance factor in PET-CT facility for the amount of exposure radiation dose received by staff. In terms of exposed radiation dose of staff, we obtained the well agreement on distance factor calculations by using Monte Carlo method. We achieved a good agreement between MCNP-X results and clinical experimental results.

Investigation of Backscattered Dose in a Computerized Tomography (CT) Facility during Abdominal CT Scan by Considering Clinical Measurements and Application of Monte Carlo Method

X-ray computed tomography (CT) related to computer-processed combination or X-ray images obtained from different angles to create patient’s cross-sectional body parts images. CT ensures to have imaging various organs, bones, blood vessel etc. and more advantageous than normal plain X-ray devices in consequence of 360 degree image of internal organs, the spine and vertebrae. For decades, Radiation protection became a main topic in research areas since CT uses various dose of X-ray for imaging body. Distance factor is the one of fundamental principle of radiation protection. Maximum dose occurs around gantry and dose rate is decreases by distance in CT facilities. To know the rate of reduction of the amount of dose by distance is very significant for radiation protection procedure especially for apply criteria of International Commission on Radiological Protection (ICRP) on radiation protection. Our study aimed to measure scattered dose rates during abdominal CT scan by considering small distance ranges from gantry until exit door and comparing the empirical result with Monte Carlo (MC) calculations. As a next step of study, we modeled a simulation input for CT facility by using MCNP-X (version 2.4.0). We obtained the changes of dose rate on distance factor by using Monte Carlo method. We achieved that MCNP-X calculations were in concordance with clinical experimental measurements. It can be concluded that Monte Carlo (MC) is an effective tool for obtain dose rate variations around CT gantry and especially radiation protection calculations in CT facilities.

Effect of Heat Treatment on Radiation Shielding Properties of Concretes

Background: Heat energy produced in nuclear reactors and nuclear fuel cycle facilities interactions modifies the physical properties of the shielding materials containing water content. Therefore, in the present paper, effect of the heat on shielding effectiveness of the concretes is investigated for gamma and neutron. The mass attenuation coefficients, effective atomic numbers, fast neutron removal cross-section and exposure buildup factors.

An Artificial Neural Network-Based Estimation of Bremsstarahlung Photon Flux Calculated by MCNPX

An Artificial Neural Network-Based Estimation of Bremsstarahlung Photon Flux Calculated by MCNPX H.O. Tekina,b,∗, T. Manici, E.E. Altunsoy, K. Yilancioglu and B. Yilmaz Uskudar University, Vocational School of Health Services, Radiotherapy Department, İstanbul, Turkey Usküdar University, Medical Radiation Research Center (USMERA), İstanbul, Turkey Uskudar University, Vocational School of Health Service, Medical Imaging Department, Istanbul, Turkey d Uskudar University, Faculty of Engineering and Natural Sciences, Molecular Biology and Genetics Department, İstanbul, Turkey Okan University, Faculity of Medicine, Department of Radiology, Istanbul, Turkey

Determining the gamma-ray parameters for BaO–ZnO–B2O3 glasses using MCNP5 code: a comparison study

ABSTRACT Rapid technological advancement has multiplied people’s exposure to ionizing radiations greatly. Widespread applications of radiation in different fields (such as agriculture, radiation therapy and scientific research fields) require that humans be protected against unnecessary exposure. In this study, mass attenuation coefficient (μm), half-value layer, mean-free path, effective atomic number (Zeff) and exposure buildup factor have been calculated for xBaO–20ZnO–(80 − x)B2O3 (x = 5, 10, 15, 20 and 25 mol%) glass systems. The mass attenuation coefficients of the selected glasses were calculated using simulation method of MCNP5 code. The simulation results have been compared with the experimental data and Xcom at the energies 223.02, 252.98, 287.28, 340.83, 398.97, 481.59, 562.68 and 662.00 keV. The agreement amounts of the mass attenuation coefficient values are from 0.2% to 2.8% and from 0.2% to 6.98% for MCNP5 and Xcom relative to experimental results, while the Monte Carlo program values are higher than that obtained by experimental data, using Xcom and MCNP5 code. The glass sample having the highest value of BaO content show high radiation shielding properties. It indicates that the MCNP5 code can be used for estimation of radiation interaction parameters where experimental results are not available.

Radiation shielding parameters of some antioxidants using Monte Carlo method

In this paper, radiation shielding parameters such as mass attenuation coefficients and half value layer (HVL) of some antioxidants are investigated using MCNPX (version 2.4.0). The validation of the generated MCNPX simulation geometry for antioxidant structures is provided by comparing the results with standard WinXcom data for radiation mass attenuation coefficients of antioxidants. Very good agreement between WİNXCOM and MCNPX was obtained. The results from the validated geometry were used to calculate the shielding parameters of different antioxidants. The radiation attenuation properties of each antioxidant were compared with each other. The results showed that, on average, the highest and the lowest radiation mass attenuation coefficients were observed on hesperidin and delphinidin chloride, respectively. It can be concluded that Monte Carlo simulation is a strong tool and an alternate method where experimental investigations are not possible and a standard simulation setup can be used in further studies for different biological structures. It can also be concluded that the obtained results from this study are very useful for radiology and radiotherapy applications where antioxidants are frequently used.