基于永磁体空间磁场检测的体内微型诊疗装置定位系统的研究

在微型诊疗装置的应用中,微型装置的体内空间定位非常重要.作者根据消化道微型诊疗装置研究的需要,设计了一种基于永磁体空间磁场检测的体内微型诊疗装置定位系统,由霍尔传感器阵列检测固定在微型装置上永磁体的空间磁场,经多路信号处理电路和单片机采集数据,再把数据通过串口通信传输给主控计算机,进而对数据分析处理计算出微型诊疗装置在体内的空间位置.实验表明,该系统可实时采集数据并可靠传输,空间磁场强度随距离有特定的变化规律,能满足实验研究的需要.     

基于磁定位的消化道微型药物释放装置动态跟踪技术研究

对消化道微型药物释放装置在体内的运动进行无创动态跟踪更具有特别重要的意义.本文在分析永磁体空间磁场分布规律的基础上,提出了利用磁定位原理实现动态跟踪微型药物释放装置在消化道运动状态的方法.其基本过程是在微型药物释放装置上固定永磁体,当其通过消化道时在体外检测磁场变化,进而实时计算出微型药物释放装置的空间位置,并描记出运动轨迹,实现动态跟踪.通过在模拟肠道中的实际测试,该技术可较好地跟踪永磁体的运动轨迹.     

基于霍尔传感器阵列的体外磁跟踪定位系统

目的为实现体内微型诊疗装置的无创定位,本文提出一种新的定位方法,并开发了一套基于此方法的实验系统.方法在分析永磁体空间磁场分布特殊规律的基础上,采用基于霍尔原理的磁场检测方法设计一种基于霍尔传感器阵列的体外磁跟踪定位系统.通过设计系统优化实验、系统性能实验以及模拟肠道平面实验验证系统的可行性、准确性及定位的精确性.结果该方法定位精度在 mm级,满足实际应用需求.结论此系统能精确确定永磁体所在空间位置,具有非接触测量、操作简单、精度高等特点,为有效监测人体肠道内的微型诊疗装置提供了基础.     

消化道应用微磁囊定位系统抗地磁干扰的补偿方法

本研究介绍了一种应用于消化道微磁囊磁定位中的补偿地磁场干扰的方法.该方法通过设置补偿值来标记地磁场的干扰水平,并且用测量值减去补偿值来达到补偿干扰的目的.通过实验表明,该方法可以准确地确定定位背心所处的地磁场干扰水平;三维跟踪轨迹表明,该方法很大程度提高了微磁囊在消化道中定位的准确度.     

胶囊状全消化道介入诊查装置的三维磁定位

为了对微型诊查胶囊进入人体消化道后的三维位置进行测量,提出了不可见状态下的非接触式永磁定位新方法.具体做法是:根据等效磁荷的原理,建立永磁体空间磁场与空间方位的简化定位模型;根据定位模型确定具体的定位方案;并对磁传感器的输出数据进行差分处理,消除了静态和准静态环境磁场干扰.实验证明定位模型能满足精度要求,定位方案正确可行,此定位法可投入实际应用.     

基于LabWindows/CVI和OpenGL的实时定位系统的界面设计

基于LabWindows/CVI快捷方便的开发环境和OpenGL的高性能和功能强大的图形库,本研究设计了一个实时跟踪胶囊内窥镜轨迹的人机界面显示系统。采用通用数据采集卡,在Windows平台下实现了胶囊内窥镜定位和显示。实验表明,此人机界面具有控制和过滤错误干扰,通用性强等功能。可以更加清晰和全面的观察胶囊内窥镜的三维轨迹。优于传统界面。     

传感器阵列数据采集和处理的虚拟仪器设计

设计了基于LabVIEW的传感器阵列数据采集和处理的虚拟仪器.使用LabVIEW编程软件,通过微机化数据采集系统和通用虚拟仪器对传感器阵列数据采集和信号处理.采用分析折线补偿法,有效减少传感器的非线性误差,提高了传感器的测量准确性.通过对每个传感器进行校正和补偿,使各个传感器的特性归一化.只要修改软件,就可以增减此虚拟仪器系统的功能.     

基于传感技术的消化道生理参数无线胶囊应用研究进展

长期以来,针对消化道生理机制的研究备受瞩目,随着传感器与检测技术的快速发展,为更多获取机体胃肠道内多种生理学信息提供了有效解决方案,其中消化道生理参数无线胶囊成为研发焦点,其适应证也被逐步拓展。该无线胶囊是利用集成传感器的微型装置获取胃肠动力的相关信息,并以此绘制出胃肠动力曲线甚至蠕动模型,为功能性胃肠病诊断及其机制探索提供了更丰富的临床证据。首先,根据无线胶囊检测信息类型的不同,分别阐述其所对应的传感器种类、原理及研究进展;随后,总结目前无线胶囊临床应用的相关研究现状,包括传输胃肠功能相关参数的检测,如pH、温度及压力,以及针对消化道理化环境状态的持续定点监测,还归纳了无线胶囊在肠道气体、菌群及消化酶等检测的功能拓展研究;最后,讨论消化道生理参数无线胶囊研发所面临的挑战和应对策略,以期为后续该领域的研究提供有用的参考信息。     

用于磁声成像研究的五自由度扫描装置的设计

本研究设计了五自由度运动控制及精确定位装置,采用NI运动控制及信号采集平台,实现了X、Y、Z方向平移以及沿Z轴旋转,同时样本载物盘沿Z轴360°旋转,使用Labview软件编程,实现实时数据采集、显示与存储。为验证装置的实用性,对其定位精度进行了考察,并以铜环为样本进行了手动控制与电机控制的电导率成像精度对比。结果表明,该运动控制定位装置能够满足磁声成像实验要求。     

胶囊内窥镜磁跟踪系统体外数据接收便携式存储装置设计

该文设计了一种无线数据接收和基于SD卡便携式存储装置,能接收体内的数据并实时写入到SD卡中,此装置可以支持MMC卡、SD卡以及SDHC卡。并使用了FAT32文件系统,将数据以文本格式(.txt)存储到SD卡,解决了胶囊内窥镜磁跟踪系统跟踪定位过程中数据量大、存储设备识别以及与上位机接口的问题。     

A portable method for assessing gastrointestinal motility by simultaneously measuring transit time and contraction frequency

To portably monitor the motility of the total GI tract, a method for assessing GI motility by simultaneously measuring transit time and contraction frequency is put forward. The portable monitoring system is composed of a swallowable telemetric capsule, a portable recorder, magnetizing coils deposited in vitro, and workstation for data processing. The transit time and contraction frequency of the GI tract are deduced by analysing the variation of the position and orientation angles of a telemetric capsule in time domain and frequency domain. AC electromagnetic localization method is used to determine the position and orientation of the telemetric capsule in vivo. In the paper, the localization model based on a quasi-static magnetic field, the method of monitoring GI motility and the set-up of the monitoring system are detailed. Then from static and dynamic experiments, the performances of the system including the accuracy and dynamic response are evaluated. Finally, the electromagnetic safety of the system is verified by simulating electromagnetic radiation to the human body.     

Arterial Head Vascularization Cartographies of Normal Metencephalic Dogs Using Magnetic Resonance Angiography

The aim of our study was to establish head arterial cartographies—useful for the diagnosis of brain diseases leading to cerebral vascular modifications—by means of magnetic resonance angiography (MRA). Casts of the arterial vascular brain system were used to corroborate the MRA results as they can be easily rotated in nonvirtual three‐dimensions and give an accurate view of the arteries calibre and origin. Two types of 3T MRA images were used: three‐dimensional fast low‐angle shot (3D‐FLASH) acquisition sequenced every 20 s, paired with injection of a paramagnetic contrast medium, and three‐dimensional time‐of‐flight (3D‐TOF) acquisition sequenced every 300 s. 3D‐FLASH acquisition gives very accurate images of the cerebral arteries and veins, but must be used with care in debilitated animals. 3D‐TOF acquisition is less accurate and gives only images of the main cerebral arteries without showing the venous system. It is, however, a viable diagnostic method for monitoring vascular lesions (e.g., cerebral hemorrhages). Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.     

人体消化道无创检测胶囊定位系统的研究进展

人体消化道无创检测系统在国内外取得了较大的成功,随着研究的深入,它必将得到广泛的应用.但对无创检测系统的胶囊定位还没有一个完美的解决方案.本文对国内外的胶囊定位系统的研究现状及其最新进展情况作了介绍,并对每一种定位方法的优缺点作了分析.     

经颅磁刺激导航个性化模型构建方法

经颅磁刺激是一种广泛应用于神经精神类疾病诊断与治疗的无创神经刺激技术,影像引导经颅磁刺激导航能够保证刺激线圈的准确定位.然而,临床禁忌症会使患者的个体影像难以获得,导致无法实现影像引导.为解决该问题,提出构建一种个性化近似影像,以替代个体影像用于导航.首先利用导航系统定位装置获取患者头皮轮廓点,并基于泊松重建算法重建头...     

A novel method of three-dimensional localization based on a neural network algorithm

In order to track the three-dimensional position of a non-invasive detecting microcapsule in the alimentary tract, a novel localization method has been developed. Three coils were respectively energized by square wave signals to generate an electromagnetic field. A 3-axis magnetic sensor was sealed in the microcapsule to measure the electromagnetic field strength. Based on the principle of magnetic dipole a corresponding localization model was established. By resolving the localization equations by means of the neural network algorithm, the spatial position of the microcapsule can be obtained. The experiment shows that the localization principle is correct and has high precision. Compared with other methods, this novel method needs no special equipment and after integration the system can be made into a portable type.     

磁感应断层成像磁力线反投影算法研究

磁感应断层成像利用涡流原理,在成像区域边界对内部磁场变化进行测量,再经过重建,获得内部电导率分布图像。其中,反投影作为一种快速重建算法,经常被应用于断层成像技术。但是,由于成像区域内磁场分布的非线性,大大降低了反投影成像的定位精度。研究检测线圈测得的相位差与成像区域磁场分布之间的关系,根据测量相位差即为成像区域内电导率分布沿磁力线路径投影的集合这一结论,设计一套适用于磁感应断层成像的反投影算法,利用成像区域磁力线的分布,构建反投影路径和区域,改善直线反投影应用于非线性场定位不准的问题。重建实验结果表明,在直径为200 mm的成像区域内,所提出算法的最小定位误差为1 mm,相对直线反投影算法提高了2～26 mm,同时重建图像在视觉质量上也有很大提高,为磁感应断层成像技术提供一种有效的重建算法。     

Navigator based respiratory gating during acquisition and preparation phases for proton liver spectroscopy at 3 T

Proton magnetic resonance spectroscopy (¹H MRS) enables the non‐invasive investigation of the human liver; however, because of technical difficulties it is not regularly used for diagnosis of liver diseases in clinical routine. Breathing motion is one of the major challenges, as it decreases spectral quality and leads to misplacement of the spectroscopic voxel. To overcome this problem, real‐time navigator gating for spectral acquisition and preparation steps (B₀ shimming, water frequency determination, receiver gain optimization, and water suppression) combined with short T_E, optimized first order projection based B₀ shimming, water suppression, and inner‐volume saturated point resolved spectroscopy (PRESS) at 3 T is suggested. Simultaneous lipid and trimethylamine quantification is demonstrated by means of phantom, volunteer, and representative patient measurements. Precise localization of the voxel despite respiratory motion, increased spectral quality (higher signal‐to‐noise ratio and reduced linewidth) compared with measurements without respiratory gating, and the possibility of acquiring data without additional subject instructions regarding breathing enable robust and accurate liver ¹H MRS measurements with this novel acquisition protocol. Copyright © 2014 John Wiley & Sons, Ltd.     

动态磁共振成像中利用时空滤波的非笛卡尔稀疏数据重建新算法

通过非笛卡尔稀疏采样,可以显著缩短磁共振成像数据采集时间,在动态磁共振中具有良好的应用前景.现有的动态图像重建算法主要利用信号在时间域上的相关性完成图像重建,对信号在空间域上的相关性探讨不足.本文提出利用时空滤波的非笛卡尔稀疏数据重建新算法,同时考虑采集信号在时间域和空间域上的相关性.对动态的磁共振数据在时间域上采用改进的Hanning滤波,以克服数据量的不足;在空间域上,引入高频增强约束以突出图像中的细节信息.仿真实验结果显示,该方法重建出时间分辨率良好、细节比较清晰的图像,实现了稀疏采集的非笛卡尔数据在k空间的重建.