环形移位悬浮存储器体系并行处理结构快速三维CT图像重建实…

ＣＴ图像重建是一种运算量很大的数据处理过程。特别是三维ＣＴ，其巨大的运算量成为该技术发展的主要障碍之一。采用并行处理技术提高运算速度被公认为是解决这一问题的最好途径。本文具体介绍了采用多处理器并行处理技术实现三维ＣＴ高速图像重建的“环形移位悬浮存储器”并行图像重建系统ＰＩＲＳ－４的体系结构和硬件、软件设计，包括系统结构与配置、交叉开关网络的设计以及控制模块的硬件细节，系统工作流程、卷积反投影图像重     

MOSSBAUER SPECTROSCOPY OF HIGH T_c YBa_2 (Cu_(3-x)Fe_x )O_y

ＭＯＳＳＢＡＵＥＲＳＰＥＣＴＲＯＳＣＯＰＹＯＦＨＩＧＨＴ＿ｃＹＢａ＿２（Ｃｕ＿（３－ｘ）Ｆｅ＿ｘ）Ｏ＿ｙ￥ＬｉＳｈｉ（李士）ａｎｄＬｉＹｉｎｈｕａ（李印华）（ＩｎｓｔｉｔｕｔｅｏｆＨｉｇｈＥｎｅｒｇｙＰｈｙｓｉｃｓ，Ｂｅｉｊｉｎｇ１０００８０，Ｃｈｉ...     

基于Windows的辐射成像图像系统

介绍了一种基于ＭＳ－ＷｉｎｄｏｗｓＮＴ的新型辐射成像图像采集、处理和分析系统。其ＭＳ－ＷｉｎｄｏｗｓＮＴ的实时硬件驱动、局域网的数据库管理、以及优秀的人机交互界面具有独特之处。该系统也为今后信息系统（ＭＩＳ）和图像存档和通讯系统（ＰＡＣＳ）的发展奠定了良好的基础。     

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     

Measurement and theoretical evaluation of cross section for Na(4D) Na(3S)→Na(4F) Na(3S)

ＭｅａｓｕｒｅｍｅｎｔａｎｄｔｈｅｏｒｅｔｉｃａｌｅｖａｌｕａｔｉｏｎｏｆｃｒｏｓｓｅｃｔｉｏｎｆｏｒＮａ（４Ｄ）＋Ｎａ（３Ｓ）→Ｎａ（４Ｆ）＋Ｎａ（３Ｓ）ＳｈｅｎＹｉＦａｎ，ＬｉＷａｎＸｉｎｇ，ＰｏｌａｔＡｈｍａｔａｎｄＬｕｏＬａｎ（Ｄｅｐａ...     

Solvent extraction of U（VI）and Th（IV）ions with N，N，N＇，N＇－tetrabutylsuccinylamid from nitric acid solutions

Ｓｏｌｖｅｎｔ　ｅｘｔｒａｃｔｉｏｎｏｆＵ（ＶＩ）ａｎｄＴｈ（ＩＶ）ｉｏｎｓｗｉｔｈＮ，Ｎ，Ｎ＇，Ｎ＇－ｔｅｔｒａｂｕｔｙｌｓｕｃｃｉｎｙｌａｍｉｄｆｒｏｍｎｉｔｒｉｃａｃｉｄｓｏｌｕｔｉｏｎｓＷａｎｇＹｏｕ－Ｓｈａｏ（王友绍），ＢａｏＢｏ－Ｒｏｎｇ...     

PIXE AND IXX ANALYSIS OF MUSEUM PAPERLIKE OBJECT

ＰＩＸＥＡＮＤＩＸＸＡＮＡＬＹＳＩＳＯＦＭＵＳＥＵＭＰＡＰＥＲＬＩＫＥＯＢＪＥＣＴＳＷｕＸｉａｎｋａｎｇ（邬显慷）（ＩｎｓｔｉｔｕｔｅｏｆＮｕｃｌｅａｒＲｅｓｅａｒｃｈ，ｔｈｅＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ，Ｓｈａｎｇａｉ２０１８０...     

Existence of the fifth unstable nuclided series

ＥｘｉｓｔｅｎｃｅｏｆｔｈｅｆｉｆｔｈｕｎｓｔａｂｌｅｎｕｃｌｉｄｅｄｓｅｒｉｅｓＺｈａｎｇＪｉａ－Ｈｕａ（张家骅）（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＮｕｃｌｅａｒＲｅｓｅａｒｃｈ，ｔｈｅＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ，Ｓｈａ...     

Transient radiation effects in CMOS inverters fabricated on SIMOX and BESOI wafers

ＴｒａｎｓｉｅｎｔｒａｄｉａｔｉｏｎｅｆｆｅｃｔｓｉｎＣＭＯＳｉｎｖｅｒｔｅｒｓｆａｂｒｉｃａｔｅｄｏｎＳＩＭＯＸａｎｄＢＥＳＯＩｗａｆｅｒｓＺｈｕＳｈｉ－Ｙａｎｇ（竺士炀），ＬｉｎＣｈｅｎｇ－Ｌｕ（林成鲁）（ＳｔａｔｅＫｅｙＬａｂｏｒａｔｏｒｙｏｆ...     

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     

A complete implementation of list-mode reconstruction for PET

Tomography reconstruction algorithm is one of the key components of positron emission tomography (PET) scanners,most PET scanners use statistical iterative reconstruction algorithms from data in sinograms currently. However tomography reconstruction using list-mode data has many unique advantages,in recent years great attention has been paid to it,being in the process of rapid development and improvement.In this paper,using experimental data of small animal PET scanner Eplus-166,exploiting ordinary subsetized list-mode EM(S-LMEM) algorithm and orthogonal distance-based ray-tracer(OD-RT),we eventually achieve list-mode tomography reconstruction.System response matrix(SRM),which establishes mapping relationship between the image and the projection space,is one key problem in iterative reconstruction algorithm.OD-RT is based on an optimization Siddon’s algorithm to calculate the SRM,generating line-of-response(LOR) which is approximately Gaussian-shaped,achieving better modeling of detector response function(DRF).The results demonstrate that image resolution recovery achieves the inherent properties of the scanner and that on-the-fly ray-tracer for real-time calculation of system response matrix is feasible for dynamic reconstruction.Meanwhile,the optimal parameters for calculating SRM are found by experiments.     

High-speed computation of the EM algorithm for PET imagereconstruction

The PET image reconstruction based on the EM algorithm has several attractive advantages over the conventional convolution backprojection algorithms. However, two major drawbacks have impeded the routine use of the EM algorithm, namely, the long computational time due to slow convergence and the large memory required for the storage of the image, projection data and the probability matrix. Here, the authors attempt to solve these two problems by parallelizing the EM algorithm on a multiprocessor system. They have implemented an extended hypercube (EH) architecture for the high-speed computation of the EM algorithm using the commercially available fast floating point digital signal processor (DSP) chips as the processing elements (PEs). The authors discuss and compare the performance of the EM algorithm on a 386/387 machine, CD 4360 mainframe, and on the EH system. The results show that the computational speed performance of an EH(3,1) using DSP chips as PEs executing the EM image reconstruction algorithm is about 130 times better than that of the CD 4360 mainframe. The EH topology is expandable with more number of PEs     

高分辨针孔SPECT三维图像重建的实现

采用一种新颖的查找表法来实施有序子集期望值最大化（OSEM）的针孔SPECT图像重建算法，有效地将针孔响应修正包含在查找表中，进而实现高分辨针孔SPECT的三维图像重建。标准Jaszczak模具的成像实验结果表明：该方法不但能显著减少图像重建过程的计算时间和内存占用，且能显著改善重建图像的分辨率。因此，查找表法是能够快速实现针孔SPECTOSEM图像重建算法，并能将针孔响应修正包含在查找表中以获取高分辨断层图像的有效方法。     

LAMOST观测控制系统体系结构的构架

体系结构的设计在整个软件的生命周期中居于重要地位,LAMOST观测控制系统的开发以体系结构为中心。在体系结构的构架中,根据LAMOST系统复杂性,研制时间长,软件生命周期长等特点、参考各种体系结构模式,采用了基于构件的层状体系结构,同时融合了MVC,代理等模式。     

RCS－Ⅰ反应堆堆芯模拟程序

本文介绍堆芯三维物理—热工水力耦台计算程序ＲＣＳ－Ｉ（ＲｅａｃｔｏｒＣｏｒｅＳｉｍｕｌａｔｏｒ）．其中子学模型采用先进的粗网格节块格林函数法，热工水力计算模型采用于通道分析方法．通过考虑多种反馈，该程序比较真实地描述堆芯的燃耗过程，具有临界、燃耗、中毒、跟踪和倒料等多种功能，可用于动力堆和研究堆的设计．     

基于硬件实现的锥束CT图像重建系统的存储机制设计

为了实现三维锥束CT图像重建加速系统的小型化,建立了基于FPGA的三维图像重建系统。并对该系统中所采用的FDK重建算法所需的数据存储量和数据传输量以及由SDRAM、SRAM和FPGA内部缓存组成的存储系统的数据吞吐率进行了研究。首先,根据FDK算法的滤波与反投影两个步骤介绍了三维锥束CT图像重建系统的数据规模。接着,介绍了一种以SDRAM为外部主存,以SRAM为外部缓存和以FPGA内部SRAM资源作为内部高速缓存的存储机制。然后,介绍了该存储机制的实现方法以及测试方法。最后对该三维图像重建系统的数据吞吐能力进行了测试,并将之与FDK算法所需的数据传输量进行了对比分析。试验结果表明:该存储机制的数据连续存取速度为151.9MB/s,数据随机存取速度为100MB/s,基本满足小规模的三维图像重建的数据存储与传输带宽的要求。     

基于微元法的高精度系统响应矩阵建模

系统响应矩阵是以矩阵形式表征的从激励到响应的数值化关系.由于绝大多数正电子发射成像的重建算法都包含正投影和反投影的计算步骤,系统响应矩阵精度是研究者普遍关心的重要因素之一.通过对系统响应矩阵进行微元法建模,提高了系统响应矩阵的精度.数值结果显示,随着微元的尺寸变小,64点微元正投影的信噪比提高了100倍以上,16线微元...     

强子探测器快速读出系统的数据压缩和并行处理

在强子探测器快速读出系统中,由于采用了一级预相符触发的方法,达到了对数据流消零(Zero Suppression)的目的,从而大大降低了数据流量;由于采用了流水线结构(PipelineArchitecture)和高速查询表(Look-up Table)相结合的并行处理方法,二级触发器可处理数据率高达16MHz以上的数据。     

Coupling DCS and MARTe: two real-time control frameworks in collaboration

Fusion experiments place high demands on real-time control systems. Within the fusion community two modern framework-based software architectures have emerged as powerful tools for developing algorithms for real-time control of complex systems while maintaining the flexibility required when operating a physics experiment. The two frameworks are known as DCS (Discharge Control System), from ASDEX Upgrade and MARTe (Multithreaded Application Real-Time executor), originally from JET.Based on the success of DCS and MARTe, ITER has chosen to develop a framework architecture for its Plasma Control System which will adopt major design concepts from both the existing frameworks.This paper describes a coupling of the two existing frameworks, which was undertaken to explore the degree of similarity and compliance between the concepts, and to extend their capabilities. DCS and MARTe operate in parallel with synchronised state machines and a common message logger. Configuration data is exchanged before the real-time phase. During the real-time phase, structured data is exchanged via shared memory and an existing DCS algorithm is replicated within MARTe. The coupling tests the flexibility and identifies the respective strengths of the two frameworks, providing a well-informed basis on which to move forward and design a new ITER real-time framework.     

Comparison of 3D OS-EM and 4D MAP-RBI-EM reconstruction algorithms for cardiac motion abnormality classification using a motion observer

Using a heart motion observer, we compared the performance of two image reconstruction techniques, a 3D OS-EM algorithm with post Butterworth spatial filtering and a 4D MAP-RBI-EM algorithm. The task was to classify gated myocardial perfusion (GMP) SPECT images of beating hearts with or without regional motion abnormalities. Noise-free simulated GMP SPECT projection data was generated from two 4D NCAT beating heart phantom models, one with normal motion and the other with a 50% motion defect in a pie-shaped wedge region-of-interest (ROI) in the anterior-lateral left ventricular wall. The projection data were scaled to clinical GMP SPECT count level before Poisson noise was simulated to generate 40 noise realizations. The noise-free and noisy projection data were reconstructed using the two reconstruction algorithms, parameters chosen to optimize the tradeoff between image bias and noise. As a motion observer, a 3D motion estimation method previously developed was applied to estimate the radial motion on the ROI from two adjacent gates. The receiver operating characteristic (ROC) curves were computed for radial motion magnitudes corresponding to each reconstruction technique. The area under the ROC curve (AUC) was calculated as an index for classification of regional motion. The reconstructed images with better bias and noise tradeoff were found to offer better classification for hearts with or without regional motion defects. The 3D cardiac motion estimation algorithm, serving as a heart motion observer, was better able to distinguish the abnormal from the normal regional motion in GMP SPECT images obtained from the 4D MAP-RBI-EM algorithm than from the 3D OS-EM algorithm with post Butterworth spatial filtering.