Tugba Manici

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.

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.

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

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.