摘要
各种原因导致的人体重要器官的缓慢出血等是导致病人死亡或预后较差的重要原因之一,目前的医学成像技术,包括CT、MRI、PET、超声等还无法对出血的过程进行长期、连续的床旁监测和监护。电阻抗断层成像是以目标体内电阻抗的分布或变化为成像对象的一种新型成像技术,作为一种廉价的无损伤检测技术,不使用核素或射线,无毒无害,因而可以成为对病人进行长期、连续图像监护的设备。本文介绍了一个基于物理模型的电阻抗成像硬件系统(FMMU V3),包括具有32个银复合电极的物理模型、采用DDS技术的恒流激励源、高精度信号检测模块、驱动测量模式程控设置模块、数据采集模块、数字I/O模块和高精度多路电源模块。该系统基于物理模型的测量数据经100次迭加后,测量精度在小信号时为1.0%,大信号时为0.1%。采用外触发DMA方式采集一组成像数据(32 X 31个)的时间小于1秒,基本满足了基于物理模型的动态成像要求,并给出了基于物理模型的初步动态成像结果。
The slowly blooding of the vital organs is one of the important factors to cause death or disabled. The common used imaging techniques, such as CT、MRI、PET and ultra sound imaging etc., can not continuously probe or monitor the blooding process for a long term on bedside. Electrical impedance tomography is a new imaging modality. Its aim is to image the conductivity distribution or changes inside the body. The advantage of such a technique over other imaging modalities is that it is harmless, relative low cost, easier to be operated, non-invasive and non-ionizing radiation. So it抯 suitable as a novel long term and continuous image monitoring equipment. In this paper, an image system of electrical impedance tomography (EIT) based on physical phantom is presented(FMMU V3). The hardware system includes a physical phantom with 32 compounded silver electrodes, a constant current source designed by Direct Digital Synthesis (DDS) technique, high accuracy measurement block, driving-mode and measuring-mode program-control block, data acquisition and digital I/O card, and high ccuracy multi-channel power supply units. Based on physical phantom after 100 times data iteration, the measurement accuracy of this system for small and large signal is 1.0% and 0.1%.Acquiring a set of measurement data (32X31) for imaging by external triggered DMA mode, the measurement time is less than one second. It satisfies the need of dynamic imaging based on physical phantom,and some preliminary dynamic images produced by the system based on physical phantom are given.
出处
《中国体视学与图像分析》
2003年第2期114-118,共5页
Chinese Journal of Stereology and Image Analysis
基金
国家九五重点攻关课题(No.96-920-12-04)资助
关键词
电阻抗断层成像
硬件系统
物理模型
Electrical Impedance Tomography
Hardware System
Physical Phantom
