An electrophoretic display driving waveform based on improvement of activation pattern

Electrophoretic display(EPD) technology has become one of the main supporting pillars of the electronic paper display industry.Despite its benefits,the EPD technology suffers from several disadvantages such as non-fixed threshold voltage value for gray scale display.In addition,the display has to repeatedly refresh between white and black states to eliminate ghost image when it needs to update a new image.The traditional driving waveform for the EPD includes four stages: erasing the original image,resetting to black state,clearing to white state,and writing a new image.A flicker can be found when transferring between two adjacent stages.A new driving waveform based on the improvement of activation pattern is proposed to weaken the ghost image and reduce the flicker.Experimental results show that the proposed driving waveform could weaken the ghost image effectively and reduce the number of flickers by 50%.Compared with the traditional driving waveform,the driving waveform of this work has a better performance.

EPID用于宫颈癌逆向调强放疗的摆位误差与质量控制

目的:探究电子射野影像系统(EPID)对宫颈癌逆向调强放疗的摆位误差的测定,并提出相应的质量控制方法。方法:将2015年2月至2017年2月在中国人民解放军南京总医院放疗科接受逆向调强放疗治疗的60例宫颈癌患者作为研究对象,对所有患者摆位误差予以测定,采用热塑成型固定膜对体位进行固定,治疗前采用加速器对每例患者正、侧位等中心验证片进行拍摄,每侧一张,1次/周,将其与治疗计划系统的数字重建放射影像(DRR)进行比较,对摆位误差予以计算。结果:60例宫颈癌患者共拍摄585张验证片,其中测定误差值≤3mm的有520张,占88. 9%(520/585),误差值≤5mm的有565张,占96. 6%(565/585);宫颈癌逆向强放疗会形成计划靶区(PTV),并存在外扩理论边界。结论:对宫颈癌逆向调强放疗给予EPID测量,能够有效测出摆位误差,明确临床靶区(CTV)到形成计划靶区外扩边界的大小,通过有效的质量控制,降低边界外扩数值,进而提升宫颈癌逆向强治疗水平。