بررسی تأثیر کاهش ولتاژ و زاویه دار کردن گانتری بر میزان دوز دریافتی لنز چشم در تصویر برداری سی تی اسکن با استفاده از کد محاسباتی MCNPx

Introduction: Eye lens is a very sensitive organ to the x-ray radiation and cataract could be formed as a result of eye exposure. Computed tomography (CT) is one of the main exposure sources in clinical situations and brain imaging delivers high amount of exposure to the eye lens. To reduce eye lens dose, efficient dose reduction methods have to be developed and implemented. In this paper, the efficiency of two methods including gantry tilting and kVp reduction, have been studied for eye lens dose reduction. Methods and Materials: A 64-slice CT scanner was modeled to evaluate the eye lens dose in different scanning arrangements using MCNPx. To study the effect of kVp reduction and gantry tilting on the Lens dose magnitudes, three tube voltages including 100, 120 and 140 kVp and three gantry tilts including 0, 15 and 30 degrees were simulated and studied. Results: The results showed that the lens dose considerably decreased by tube voltage decreasing and gantry tilt increasing. Discussion and Conclusion: From the results, it could be concluded that low tube voltage and gantry tilting are effective and simple methods for lens dose reduction in CT scan.