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Study on the Characteristics of X-ray Spectra in Imaging Diagnosis Using Monte Carlo Simulations
Khanh Ai Tran,Loan Thi Hong Truong,Nhon Van Mai,Phuong Nguyen Dang,Dung Thi Thuy Vo 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.7
X-rays are widely used in diagnostic imaging such as radiography and computed tomography. An understanding of the X-ray spectrum is essential for estimating the dose absorbed by the patient and for improving image quality. In this research, X-ray emission spectra were investigated by using two different approaches: a Monte Carlo method using the MCNP5 code and a semi-empirical calculation with SpekCalc software. The results were compared with each other to validate the Monte Carlo simulation of the X-ray spectra, so that the simulation model can be applied to estimating the dose rate distribution in X-ray imaging. The obtained results show good agreement between the two approaches, but some divergence is still observed in the characteristic X-ray peaks. In addition, the influence of X-ray tube parameters such as the peak voltage, filter, anode angle and target material on of the beam quality was investigated.
Hang Nguyen Thai Phung,Van Nguyen Khanh Tran,Phuong Ai Duong,Hung Vu Tuan Le,Nguyen Duc Truong 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.70 No.11
Mono, co- and tri-doped TiO2 thin films with the transition metals (vanadium and/or chrominium) and a nonmetal (nitrogen) have been fabricated by sol-gel method. X-ray diffraction results clearly reveal anatase crystal structure for all obtained samples and doping with any dopants doesn’t change the anatase phase of TiO2. Compared to TiO2, three types of doped TiO2 thin films exhibit a red-shift in the absorption edge and have much better photocatalytic properties for methylene blue degradation in visible light region. The maximum visible-photocatalytic performance was achieved for tri-doped TiO2 sample. The mechanism for enhancing visible-photocatalytic activity of co-doped and tri-doped TiO2 thin films was also examined.