摘要：For cone beam computed tomography(CBCT),there has long been a desire to modulate the intensity and distribution of the X-rays to accommodate the patient’s anatomy as the gantry rotates from one projection to *** would reduce both image artifacts and radiation ***,the current beam modulation setups,such as dynamic bowtie filters,may be too complex for practical use in clinical *** study aimed to investigate a simplified dynamic beam filtration strategy for CBCT imaging to reduce image artifacts and radiation *** this study,the beam filtration was designed to vary dynamically as the CBCT gantry rotates around the ***,two distinct components were integrated:the sheet filter part and the bowtie filter *** dynamic beam filtration setup has two working schemes,one is a combination of dynamic sheet filter and dynamic bowtie filter,denoted as dynamic filterdynamic bowtie(DFDB);the other is a combination of dynamic sheet filter and static bowtie filter,denoted as dynamic filter-static bowtie(DFSB).Numerical imaging experiments were performed for three human body parts:the shoulder,chest,and *** addition,the Monte Carlo simulation platform MC-GPU was used to generate the dose distribution *** showed that the proposed DFDB and DFSB beam filtration schemes can significantly reduce the image artifacts and thus improve the CBCT image *** on the scanned object,the total radiation dose could be reduced by 30%.The proposed simple dynamic beam filtration strategy,especially the DFSB approach,could be beneficial in the future to improve the CBCT image quality with reduced image artifacts and radiation dose.

摘要：根据当前缠绕成型生产线自动化程度不高等情况,研发和设计了一套自动存取设备,以提高芯模的存取效率,从而大大提高芯模的生产效率。文中对玻璃钢管道缠绕芯模自动存取机结构进行设计,采取垂直旋转式立体仓库作为芯模存储形式、多支撑点稳定支撑、垂直循环传动、单链轮导轨式传动结构、直角坐标式搬运机械手装卸芯模方案、液压升降同步控制回路等技术措施,既提高了在纤维管道制作过程中芯模的自动存取效率,又降低了芯模在运输过程中的危险性。利用SolidWorks完成三维建模,阐述各部件功能实现原理,完成了搬运机械手的结构和芯模自动存取搬运系统的设计。根据搬运方案对搬运机械手X、Y、Z轴分别进行结构设计和建模,对Z轴液压同步控制回路进行设计。运用Ansys Workbench对搬运机械手的X轴支撑架进行了力学特性分析,并采用基于响应面的多目标遗传算法对X轴支撑架进行优化分析,提高了结构的可靠性和稳定性。