成人大骨节病治疗中膝关节形态的X线测量

[摘要] 目的 通过对大骨节病（Kaschin Beck disease, KBD）患者膝关节中髌骨及髌股关节形态学参数的X线观测，探寻KBD的膝关节形态变化规律，为临床诊疗提供参数资料，为关节置换提供参数支持。方法 对84例KBD住院患者的膝关节的X线片及相关的临床资料进行了回顾性分析。在X线片上进行了Kellgren -Lawrence及髌骨分型，测量了Insall 指数、外侧髌股角、沟角、适合角、髌骨外移率、髌股指数等形态学参数与症状、疗效之间相关性。结果 参数严重性越高，KBD临床表现越重，临床疗效越差，KBD临床症状越重，效果越差。结论 膝关节X线参数可以作为KBD治疗效果和预后判断的重要参数。     

X线机监控系统的设计

目的:本文以上球管X线机为例,介绍了应用Visual Basic高级语言设计一种监控系统平台,实现对X线机设备的开关机、床面转动、片盒尺寸设置等状态的全面监控。方法:在Visual Basic6.0环境下,运用MSCOMM串行接口通信技术,建立上位机控制平台,通过平台的设置参数,并通过串口发送命令给下位机,从而控制X线机运行状态。结果:实现了通过平台发送命令,来控制X线机床面板和球管的上下、左右以及转动等运行状态;用户可以通过平台设置X线机的片盒尺寸、曝光大小的参数以及滤线器状态。该软件经过多次实验应用,取得良好效果。结论:本文在Visual Basic6.0软件平台下,建立了一个X线机监控系统平台,实现了对X线机设备的开关机、床面转动、片盒尺寸设置等状态的全面监控,并通过了多次实验室应用。     

X光机双操作台的通信设计

目的:维修工作者在调试维修X线机的过程中通常存在一个麻烦:维修者在X线机机房内调试机器时每调节一次X线机曝光参数则需要往返一次控制室与机房。为了解决这个麻烦,提出了开发第二操作台并置于X线机房内的方案,以减少维修者往返控制室与机房的次数。方法:针对X671A型高频高压X光机设计了一个基于P89C669芯片的双操作台。第一操作台是一个实际的操作控制台,第二操作台为一台PC机。通过设定通信协议并调试软件,完成两个操作台的参数设置与显示、接收与发送命令等功能。结果:实现了机房和控制室各具有一个功能相同的操作台,使维修人员在机房内就可以通过使用第二操作台调节X线的曝光参数,从而调试维修X线机,极大方便了维修人员的工作。结论:对其它医学仪器的虚拟操作台设计,该方案具有重要的借鉴意义。     

微焦点X线相衬成像技术的边缘信号增强特性研究

目的：研究确定微焦点X射线相衬成像技术的边缘信号特性,以更好地从理论和实验角度,来解读X射线相衬成像结果中的图像信息,更好地确定基于微焦点的X射线相衬成像设备中的相关成像参数,以提高X射线相衬成像技术的应用效果。方法：本文以X射线的折射现象为物理基础,将菲涅耳衍射理论和傅立叶变换相结合,建立X线相衬图像对物体相位信息的二阶微分理论模型,揭示了微焦点X线相衬成像技术的边缘结构信号增强特性及其内涵。再通过计算机仿真实验和对真实光纤样品的物理实验,来观察和验证X线相衬成像技术的边缘结构信号增强特性。结果：计算机仿真实验和对真实光纤样品的物理实验的一致结果显示：基于微焦点的X线相衬成像技术,对样品的边缘结构信息具有明显的信号增强特性,通过相衬图像能够突出显示弱对比物体内部结构的边缘信息。结论：X线相衬成像是一种全新的成像方法,它弥补了传统成像方法在对弱吸收物质成像上的不足,研究证实,这种技术具有对样品内部的微细结构进行边缘增强的成像特性,这为进一步的技术开发和设备参数的优化提供了很好的研究基础。     

股骨上端几何参数测量与动态分类

通过对84根完好的中国人成人股骨标本进行正位和侧位两个方向的X线摄影,得到股骨正、侧两方位的X光片。对每一股骨的X光片进行14个参数的测量。并以动态自组织方法将得到的各测量参数进行分类,从而得到股骨上端相应几何参数的分布规律,为中国人种的人工髋关节设计提供基本依据。     

一种乳腺钼靶X线图像的软拷贝显示优化方法

数字乳腺钼靶X线图像比胶片乳腺X线图像能更有效地表现和检测乳腺病变,本研究提出了针对DICOM 格式乳腺钼靶X线图像的高效软拷贝显示方法.通过提取图像中的乳腺区域获得对初始窗口参数的准确估计,使乳腺组织在图像初始显示时就有比较好的对比度.利用乳腺区域分割结果,交互调窗操作时只更新乳腺区域内部像素的显示灰度,背景区域像素灰度保持不变;用整数运算和移位运算实现了多项式插值函数,优化了频繁调用的图像缩放操作.算法能显著提高乳腺钼靶X线图像软拷贝显示效率.     

X线机工作特性模拟实验装置设计与研制

目的:解决在医学影像技术专业和医学影像学专业实验教学中X线机实验设备成本高、有辐射和电路封装等缺点。方法:以X线机基本电路为基础,优化电路结构、采用直观功能模块电路设计,并以电源变压器为管电压测量电路和管电流测量电路提供直流电;使用89C2051单片机,用于曝光时间设定、曝光时间控制、显示电路控制驱动等多种功能。结果:本装置优势为不产生高压和X射线,可以模拟医用X线机的工作原理和主要电路结构,可用于开设X线机实验课,供学生学习和掌握X线机的工作原理及电路结构,测量X线机的主要工作特性和参数,观察和测量电路波形。结论:该设备可以解决实验教学设备不足,可广泛用于医学院校医学影像学、医学影像技术等相关专业的实验教学。     

工频X线机和中频X线机在胸部计算机X线摄影中应用分析

目的分析工频X线机和中频X线机在胸部计算机X线摄影(CR)中的图像质量,监测相应辐射剂量,比较两种X线机在CR摄影中的适用性。方法使用工频X线机和中频X线机摄取2～3岁小儿胸片共28例,分析图像质量,监测辐射剂量;并对两种X线机高压输出及IP对X线吸收特点进行分析。结果同工频X线机相比,中频X线机更易获得优质图像,且降低了辐射剂量。结论在CR应用中,中频X线机比工频X线机有明显优势。     

人工髋关节股骨假体柄上部的形态曲线设计

通过对84根中国人成人股骨标本进行正侧位X线摄影,在X线片上对股骨上部髓腔内壁的连续形态进行描绘,将描绘好的图像输入计算机,由计算机进行图像处理后提取其曲线形态数据,并将形态数据参数化.将各项参数化数据按分布方式进行分类,根据分类结果得到符合生物力学特性的系列型人工髋关节柄上部的形态曲线.     

诊断X线机辐射剂量的测量

为提高诊断X线机的诊断质量,促进放射防护工作的开展,根据"国际辐射单位和测量委员会"(International Commission on Radiological Units and Measurements,ICRU),"国际放射防护委员会"(International Commission on Radiation Protection,ICRP)关于辐射对人体的损害之划分标准,作者对岛津制作所90年代中期生产的XEB150L-20型500mA X线机按照国家规定的要求及有关标准,分别对辐射空气释动能率,半价层,输入量重复性,输出量线性,高对比分辨率,光野与照射野一致性及X线管的焦点等参数进行了测试。分析了测试的数据与结果,并进行了简要的评价。     

Logarithmic amplifier for computed tomography tasks using fluoroscopic projections

The image intensifier (II)-based imaging systems, as radiotherapy simulators or C-arm X-ray units, have also been used for image acquisition in computed tomography. When analogue-to-digital conversion is performed on the output signal of the television camera, the accuracy for low-amplitude video signals, corresponding to X-ray pathways crossing high attenuation structures, is limited. To deal with this lack of accuracy, we investigated the benefits of using a logarithmic amplifier (LOGAMP) inserted between the television camera output and the analogue-to-digital converter (ADC) in the image acquisition chain. Such a device was intended to provide better use of the available ADCs of a given resolution and actually to reduce the quantization noise. Simulated data were used in this study, and cases with and without logarithmic amplifier were compared. Based on the simulation results, we formulate requirements for several signal and acquisition system parameters where the use of such a circuit is recommended.     

Logarithmic amplifier for computed tomography tasks using fluoroscopic projections

The image intensifier (II)-based imaging systems, as radiotherapy simulators or C-arm X-ray units, have also been used for image acquisition in computed tomography. When analogue-to-digital conversion is performed on the output signal of the television camera, the accuracy for low-amplitude video signals, corresponding to X-ray pathways crossing high attenuation structures, is limited. To deal with this lack of accuracy, we investigated the benefits of using a logarithmic amplifier (LOGAMP) inserted between the television camera output and the analogue-to-digital converter (ADC) in the image acquisition chain. Such a device was intended to provide better use of the available ADCs of a given resolution and actually to reduce the quantization noise. Simulated data were used in this study, and cases with and without logarithmic amplifier were compared. Based on the simulation results, we formulate requirements for several signal and acquisition system parameters where the use of such a circuit is recommended.     

基于LabVIEW显微CT图像采集控制系统软件的设计

背景：LabVIEW作为著名的虚拟仪器开发平台,数据采集、信号处理与分析是其强项与优势。 目的：设计一套完整的CT控制与图像采集系统应用程序。 方法：通过LabVIEW8.5虚拟仪器开发平台,设计CT控制及图像采集系统,与X射线源、转台以及探测器等硬件仪器一同构建了一套完整的高分辨率显微CT成像系统。 结果与结论：将该软件与实验室显微CT硬件系统配合进行实验,很好的实现了对平台参数的设置及初始化、对载物台移动的控制、CT图像采集并保存和读取等功能,成功构建了一套显微CT图像采集控制系统软件,系统参数可根据实际需要修改,长期运行性能稳定。     

Mammogram synthesis using a 3D simulation. I. Breast tissue model and image acquisition simulation

A method is proposed for generating synthetic mammograms based upon simulations of breast tissue and the mammographic imaging process. A computer breast model has been designed with a realistic distribution of large and medium scale tissue structures. Parameters controlling the size and placement of simulated structures (adipose compartments and ducts) provide a method for consistently modeling images of the same simulated breast with modified position or acquisition parameters. The mammographic imaging process is simulated using a compression model and a model of the x-ray image acquisition process. The compression model estimates breast deformation using tissue elasticity parameters found in the literature and clinical force values. The synthetic mammograms were generated by a mammogram acquisition model using a monoenergetic parallel beam approximation applied to the synthetically compressed breast phantom.     

Object-based three-dimensional X-ray imaging

A form of three-dimensional X-ray imaging, called Object 3-D, is introduced, where the relevant subject material is represented as discrete ‘objects’. The surface of each such object is derived accurately from the projections of its outline, and of its other discontinuities, in about ten conventional X-ray views, distributed in solid angle. This technique is suitable for many applications, and permits dramatic savings in radiation exposure and in data acquisition and manipulation. It is well matched to user-friendly interactive displays.     

Wavelength optimization for rapid chromophore mapping using spatial frequency domain imaging

Spatial frequency-domain imaging (SFDI) utilizes multiple-frequency structured illumination and model-based computation to generate two-dimensional maps of tissue absorption and scattering properties. SFDI absorption data are measured at multiple wavelengths and used to fit for the tissue concentration of intrinsic chromophores in each pixel. This is done with a priori knowledge of the basis spectra of common tissue chromophores, such as oxyhemoglobin (ctO(2)Hb), deoxyhemoglobin (ctHHb), water (ctH(2)O), and bulk lipid. The quality of in vivo SFDI fits for the hemoglobin parameters ctO(2)Hb and ctHHb is dependent on wavelength selection, fitting parameters, and acquisition rate. The latter is critical because SFDI acquisition time is up to six times longer than planar two-wavelength multispectral imaging due to projection of multiple-frequency spatial patterns. Thus, motion artifact during in vivo measurements compromises the quality of the reconstruction. Optimal wavelength selection is examined through matrix decomposition of basis spectra, simulation of data, and dynamic in vivo measurements of a human forearm during cuff occlusion. Fitting parameters that minimize cross-talk from additional tissue chromophores, such as water and lipid, are determined. On the basis of this work, a wavelength pair of 670 nm∕850 nm is determined to be the optimal two-wavelength combination for in vivo hemodynamic tissue measurements provided that assumptions for water and lipid fractions are made in the fitting process. In our SFDI case study, wavelength optimization reduces acquisition time over 30-fold to 1.5s compared to 50s for a full 34-wavelength acquisition. The wavelength optimization enables dynamic imaging of arterial occlusions with improved spatial resolution due to reduction of motion artifacts.     

量子成像及其生物医学应用进展

量子成像是是利用辐射场的量子涨落来获取物体信息的一种非局域成像方法。本文介绍了量子成像的一般概念,包括其理论基础、实验装置和发展历史。基于它在空间分辨率、抗干扰能力和图像采集时间等方面的独特优势,本文介绍了其在生物医学领域的潜在应用前景,主要应用有:鬼磁共振血管造影技术,量子成像可以在更大的并行加速因子条件下,近乎完美地对背景噪声进行抑制;量子光学相干断层扫描技术,量子成像在处理群速度色散和图像分辨率方面有着绝对优势;X射线量子成像,可以在保持图像质量的前提下降低辐射剂量。此外,若在单像素成像实验中考虑介质的多重散射,量子成像则可以实现对生物组织的单像素透射成像。     

High-resolution 8 Tesla imaging of the formalin-fixed normal human hippocampus

The purpose of this study was to evaluate the capacity of high-resolution magnetic resonance imaging (MRI) to visualize the normal anatomic features of the human hippocampus in vitro, using high field imaging equipment, parameters, and acquisition times appropriate for imaging human subjects in vivo. This research compared high field, high-resolution MRI of formalin-fixed normal human hippocampus specimens to histologic sectioning of the same hippocampus samples. Four specimens were evaluated using an 8 Tesla (T), 80 cm bore whole-body MRI scanner equipped with a 12.7 cm single strut transverse electromagnetic resonator (TEM) coil. Hahn spin echo images were acquired with a repetition time (TR) of 800 msec, echo times (TE) of 20, 50, 90, and 134 msec, and an acquisition time (TA) of 3.25 min. The image quality was superb with demonstration of most of the features of the hippocampus. High field, high-resolution MRI can be used to depict multiple layers of the formalin-fixed human hippocampus in vitro using an 8 T whole-body scanner, a TEM coil, and short acquisition times compatible with human imaging in vivo.     

Normalized glandular dose (DgN) coefficients for flat-panel CT breast imaging

The development of new digital mammography techniques such as dual-energy imaging, tomosynthesis and CT breast imaging will require investigation of optimal camera design parameters and optimal imaging acquisition parameters. In optimizing these acquisition protocols and imaging systems it is important to have knowledge of the radiation dose to the breast. This study presents a methodology for estimating the normalized glandular dose to the uncompressed breast using the geometry proposed for flat-panel CT breast imaging. The simulation uses the GEANT 3 Monte Carlo code to model x-ray transport and absorption within the breast phantom. The Monte Carlo software was validated for breast dosimetry by comparing results of the normalized glandular dose (DgN) values of the compressed breast to those reported in the literature. The normalized glandular dose was then estimated for a range of breast diameters from 10 cm to 18 cm using an uncompressed breast model with a homogeneous composition of adipose and glandular tissue, and for monoenergetic x-rays from 10 keV to 120 keV. These data were fit providing expressions for the normalized glandular dose. Using these expressions for the DgN coefficients and input variables such as the diameter, height and composition of the breast phantom, the mean glandular dose for any spectra can be estimated. A computer program to provide normalized glandular dose values has been made available online. In addition, figures displaying energy deposition maps are presented to better understand the spatial distribution of dose in CT breast imaging.