SPECT质量保证现状分析

ＳＰＥＣＴ质量控制和质量保证是保证ＳＰＥＣＴ图像质量的重要内容，通过对广东省ＳＰＥＣＴ质控网断层分辨率模型测试情况及结果分析，讨论ＳＰＥＣＴ质量保证现状及各种采集和重建条件的选择。     

SPECT显像对小儿脑梗塞的研究

为了探讨ＳＰＥＣＴ对小儿脑梗塞（ＣＣＩ）的诊断价值，对２６例患儿采用ＳＰＥＣＴ局部脑血流灌注（ｒＣＰ）显像与ＣＴ对比研究，结果表明，脑梗塞灶及远隔区域的ｒＣＰ减少，ＳＰＥＣＴ和ＣＴ的阳性率分别为９２．３％（２４／２６）和８４．５％（２２／２６），两者无显著性差异（Ｐ〉０．０５），而发病２天以内９例的ＳＰＥＣＴ阳性率１００％（９／９）显著高于ＣＴ５５．６％（５／９）（Ｐ〈０．０５），提示ＳＰＥＣＴ显     

脑外伤患者的SPECT显像与CT对比观察

对４８例脑外伤２进行了＾９９ｍＴｃ－ＥＣＤ ＳＰＥＣＴ脑血流灌注显像。其中４１例在ＳＰＥＣＴ检查的前后两周同时行脑ＣＴ检查，结果ＳＰＥＣＴ对轻、中、重型外伤的检出率分别为６０％、９０％和１００％；而ＣＴ分别为１０％、６０％和１００％，同一病人中ＳＰＥＣＴ比ＣＴ发现的病灶早、数目多，范围大。对脑外伤综合征及后遗症ＳＰＥＣＴ检出率分别为８０％和９０％，ＣＴ分别为２５％和７１．４２％。显然ＳＰＥＣＴ探测     

脑SPECT在癫痫儿童中的应用

对１５例儿童癫痫进行发作间期ＳＰＥＣＴ脑局部血流显像，部分患者同时进行了ＥＥＧ、ＣＴ、ＭＲＩ检查。结果显示ＳＰＥＣＴ阳性率最高，ＥＥＧ次之，ＣＴ、ＭＲＩ检出率的低于前二者，表明ＳＰＥＣＴ脑血流显像是诊断儿童癫痫灶的有效方法，且对癫痫儿童的预后，局部脑血流变化与临床表现的演变之间关系等研究有帮助。     

SPECT显像在神经疾患中应用的意义和评价

对１５８例（急性脑血管病８４例，癫痫５０例，脑肿瘤１２例，偏头痛７例，震颤麻痹５例）常见脑部疾患进行了ＳＰＥＣＴ脑血流显像，其结果与ＣＴ比较，表明ＳＰＥＣＴ对脑梗塞和ＴＩＡ的早期诊断优于ＣＴ，但ＣＴ对急性脑血管病的定位和定性诊断优于ＳＰＥＣＴ。ＳＰＥＣＴ对癫痫的诊断具有独特的价值，但对脑肿瘤和震颤麻痹的诊断无肯定的价值。     

SPECT在缺血性脑血管疾病中的临床应用

应用＾９９Ｔｃ－ＥＣＤ对３２９例缺血性脑血管病患者进行ＳＰＥＣＴ检查（其中脑梗塞１６０例，脑动脉硬化１２０例，椎基底动脉供血不足３０例，短暂性脑缺血发作（ＴＩＡ）１９例），并将部分病例的ＳＰＥＣＴ结果与Ｘ组ＣＴ作比较，脑梗塞、脑动脉硬化、椎基底动脉供血不足、ＴＩＡ ＳＰＥＣＴ阳性率分别为９０．６％、８９．２％、８６．７％及８４．２％。３２９例中ＳＰＥＣＴ阳性者２９４例，总阳性率为８９．４％，而Ｘ线     

SPECT系统中局部触发方法的应用

本文介绍了局部触发电路的设计，并将其应用于模块化环形码头ＳＰＥＣＴ系统（ＭｃＳＰＥＣＴ）中，对该方法的应用效果进行了测试。     

多数字信号处理器在SPECT数据采集系统上的应用研究

本文介绍了环境探头ＳＰＥＣＴ数据采集系统利用数字信号处理器技术的几种方案，并在现有的ＭｃＳＰＥＣＴ系统上对几种方案进行测试比较。     

不同厂家SPECT平面固有性能测试结果的分析

分析比较了４个不同厂家生产的ＳＰＥＣＴ的固有泛源均匀性和最大计数率的测试结果。发现在ＳＰＥＣＴ正常运转的情况下实际测得的平面固有性能有所不同，且有的差异显著。     

SPECT脑血流灌注显像应用于脑血管疾病

７０例脑血管疾病患者（脑梗塞、ＴＩＡ、ＶＢＩ）行＾９９ｍＴｃ－ＥＣＤ ＳＰＥＣＴ脑血流灌注显像，并与ＣＴ、ＭＲＩ对照，结果ＳＥＰＣＴ诊断脑血管病的阳性率为９０％。ＣＴ为８８．２％（４５／５１），ＭＲＩ为９０％（２７／３１）。脑梗塞５５例中５１例ｒＣＢＦ图像上出现血流灌注减低区，４例发现交叉性小脑神经机能失联络证。诊断ＴＩＡ、ＶＢＩ的阳性率为７５％。ＳＰＥＣＴｒＣＢＦ显像发现病灶较ＣＴ、ＭＲＩ多；可     

A high-resolution small animal SPECT system developed at Tsinghua

An SPECT system dedicated to small animal imaging shall be of a millimeter spatial resolution or even better.This study was aimed at achieving 0.5-mm spatial resolution for a small animal SPECT system at low cost.It was developed from a single-head clinical SPECT scanner,with a seven-pinhole collimator and a four-degree-offreedom motion control stage.Several key techniques were developed,including high-resolution image reconstruction algorithm,high accuracy geometrical calibration method,and optimized system matrix derivation scheme.The system matrix was derived from Monte-Carlo simulation and de-noised by fitting each point spread function to a two dimensional Gaussian function.Experiments of point source and ultra micro hot rod phantom were conducted.With a spatial resolution of 0.5-0.6 mm,this system provides a practical way for low-cost high-resolution animal imaging on a clinic SPECT system.     

Investigation of 90° dual-camera half-fanbeam collimation formyocardial SPECT imaging

This study investigated several aspects of the use of half-fanbeam collimation with a 90° dual-camera system for myocardial single photon emission computed tomography (SPECT) imaging. The detection efficiency, relative to parallel-hole collimation, was evaluated for a range of focal lengths and radii of rotation (ROR) to determine if there was an optimum focal length, which maximized the detection efficiency. In addition, sinograms were constructed and a simulation study was performed to determine if there was an optimal camera system rotation that maximized the total acquired myocardial counts while providing sufficient angular sampling for the myocardial region. Finally, artifacts in images reconstructed from data acquired over various system rotations were evaluated using simulated and experimental data. There existed an optimal collimator focal length for a given ROR; but it varied with ROR. Relative to parallel-hole collimation, the detection efficiency for half-fanbeam collimation was roughly 20% greater, for cast collimators constructed using the same pins and thickness. The theoretical minimum system rotation for sufficient sampling of the myocardial region ranged from 124° to 148° for RORs ranging from 13 to 25 cm, respectively. The total number of acquired myocardial counts was relatively constant for system rotations of 90° to 360°. Myocardial SPECT images reconstructed iteratively with attenuation compensation from half-fanbeam data collected over system rotations ranging from 135° to 360° showed no artifacts in the myocardial region. Based on these results, the authors concluded that there was no single optimum system rotation, but that a system rotation of 180° centered at 45° left anterior oblique was a good, practical minimum rotation. Half-fanbeam collimation is a useful alternative system configuration for myocardial SPECT imaging     

High-resolution SPECT for small-animal imaging

1Introduction The rapid advance in molecular biology and the increasing use of transgenic mice as models of human biology and diseases have led to significant interests in the development of noninvasive,high-resolution,in vivo imaging techniques for small animals[1-4].Medi-cal imaging techniques including ultrasound(US),computed tomography(CT),magnetic resonance im-aging(MRI),positron emission tomography(PET),and single-photon emission computed tomography(SPECT),are contributing to this …     

Helical SPECT using axially truncated data

In this study, use of a helical orbit in performing a long object SPECT scan with parallel, cone, fan, rotated fan, varying focal-length cone, divergent, and astigmatic collimators is proposed. Sufficient-data scanning helical orbits for these collimation geometries are developed. Both a single-detector system and a multi-detector system are considered. In order to verify the authors' orbit design requirement, the iterative ML-EM algorithm is used to reconstruct images of a long Defrise phantom. The phantom height is five times the height of the detectors. Computer simulations are performed and exact reconstructions are obtained. The proposed sufficient helical orbit pitch will facilitate performing whole body SPECT and PET scans that demand an exact reconstruction     

SPECT质量控制通用测试系统设计

本研究的目的旨在按NEMA标准设计一套通用的SPECT质量控制测试系统,供各种型号SPECT的验收,性能比较和常规质控使用。本系统以国内相当普及的IBM PC系列机作为工作平台。性能测试数据在不同型号的SPECT上采集后,通过计算机接口传送到IBM PC机,使用一个统一的软件进行测算。 本文包括接口设计和SPECT测试程序设计两部分,讨论了RS232串行接口管理程序的编制,SPECT测试程序数学模型和设计技巧,对SPECT测试程序设计中普遍遇到的问题做了详细分析、计算与讨论。SPECT质控测试系统包括11个子程序,用于测量γ相机和SPECT的主要性能指标。该系统在OMEGA 500/MCS 560 SPECT上使用,结果表明:系统操作简便、速度快、通用性好,能客观地反映SPECT的性能。     

SPECT: Single Photon Emission Computed Tomography

Interest in single photon emission computed tomography (SPECT) has been renewed as a result of the successful application of transmission (x-ray) CT to diagnostic radiology. Many aspects of SPECT are different from those encountered in transmission CT, and often are more difficult to overcome. Examples of two major aspects encountered are 1) the limitations on the available photon flux imposed mainly by dose considerations to the patient and, 2) the internal attenuation of gamma rays within the patient prior to detection. Progress has been made recently in overcoming the quantum limitation by designing SPECT systems using special collimation and large active detector areas. High efficiency systems have been designed and built using both multiple-scanners and also using multiple large-field-of-view scintillation cameras. Much progress has also been made in compensating for the problem of gamma ray attenuation using iterative and analytical approaches. This paper reviews the history of single photon emission tomography, characterizes the physical attributes of SPECT, describes some solutions to the inherent problems encountered, and also reviews a few selected approaches in designing SPECT systems to provide high quality, artifact-free reconstructed images. It is anticipated that future developments will allow SPECT systems to more nearly attain the ultimate goal of determining absolute regional radionuclide concentration as a function of time. These systems, coupled with newly developed physiological radiopharmaceuticals, can provide useful research and clinical information.     

门电路心血池断层与平面显像的临床应用及探讨

对３０例病人进行了门电路心血池断层及平面显像，发现断层显像ＬＶＥＦ与平面显像ＬＶＥＦ呈良好正相关（ｒ＞０．７，Ｐ＜０．０００１），而断层显像ＲＶＥＦ与平面显像ＲＶＥＦ无相关关系（ｒ＜０．５，Ｐ＞０．０５）。左右心室舒张末期及收缩末期容积有显著性差异（Ｐ＜０．０５），门电路心血池断层显像能够克服平面显像心房心室互相重叠的影响。有利于对左右心室底部及间隔病变的检查。     

An iterative image reconstruction algorithm for SPECT

Properties of two algorithms for iterative reconstruction of SPECT images, LS-MLEM and LS-OSEM,are studied and compared with the ML-EM algorithm in this paper. By using projection data of heavy-noise, their effectiveness in improving SPECT image quality is evaluated. A phantom with hot and cold lesion is used in the investigation. The reconstructed images using LS-MLEM or LS-OSEM show that there is not a rapid increase in image noise,and the ＂best＂ estimate is assuming that the reconstructed images satisfy the statistical model. The major advantage of using LS-MLEM or LS-OSEM algorithm in SPECT imaging is in their ability to accurately control for heavy-noise. And LS-OSEM algorithm obviously improves the convergence rate.     

An analytical simulation technique for cone-beam CT and pinhole SPECT

This study was aimed at developing an efficient simulation technique with an ordinary PC.The work involved derivation of mathematical operators,analytic phantom generations,and effective analytical projectors developing for cone-beam CT and pinhole SPECT imaging.The computer simulations based on the analytical projectors were developed by ray-tracing method for cone-beam CT and voxel-driven method for pinhole SPECT of degrading blurring.The 3D Shepp-Logan,Jaszczak and Defrise phantoms were used for simulation evaluations and image reconstructions.The reconstructed phantom images were of good accuracy with the phantoms.The results showed that the analytical simulation technique is an efficient tool for studying cone-beam CT and pinhole SPECT imaging.