医学三维成象

本先介绍了三维成象技术在科研，临床中的应用，并介绍了直接三维显示法，表面显示法，体绘制技术等三种三维立体景象显示方法。其中表面显示法比较成熟，已经处于应用阶段，体绘制技术是一种有潜力的显示方法，直接三维显示法目前只处于研究阶段。     

《立体定向和功能性神经外科杂志》征稿通知

《立体定向和功能性神经外科杂志》是中华神经外科学会立体定向和功能性神经外科专业委员会的专业学术性期刊，国际标准号：ISSN1008—2425，国内刊号：CN34一1168／R。本刊主要报道立体定向和功能性神经外科的研究动态、科研成果以及临床应用的研究，是神经外科、神经内科和精神科工作者的专业学术刊物。主要刊登内容：立体定向技术和神经外科导航技术的临床应用，微侵袭神经外科手术，神经内窥镜技术，DBS技术研究与应用，运动障碍性疾病、精神病、疼痛、癫痫等的基础研究与临床内外科治疗，立体定向放射外科治疗，神经组织移植与基因治疗等。     

医学三维成象

本文先介绍了三维成象技术在科研、临床中的应用,并介绍了直接三维显示法、表面显示法、体绘制技术等三种三维立体景象显示方法。其中表面显示法比较成熟.已经处于应用阶段,体绘制技术是一种有潜力的显示方法。直接三维显示法目前只处于研究阶段。     

脑立体定位技术在光遗传学中的应用

近年来光遗传学技术迅速发展，并且在现代神经生物学领域应用广泛，规范精准的技术操作在科学实验中至关重要，而当前对光遗传学研究领域中应用脑立体定位技术的相关方法的资料较少。以病毒转染实现视蛋白的表达为例，详细阐述了在光遗传学研究领域中应用脑立体定位技术的方法，包括确定坐标、病毒载体的选择与保存，脑立体定位病毒注射，埋光纤及行为学等测试等方面，详细阐述了操作过程中的注意事项，以及目前脑立体定位技术的局限和未来的发展方向等，旨在为脑科学研究提供参考。     

用液晶开关实现RDS立体成像的方法学研究

本文报道以ＲＤＳ立体图作为检测图形，用液晶开关实现其三维立体显示的一些探索性研究，用液晶开关眼镜作为立体图的同步分离部件。使得本系统建立于继时法成像的基础上，因而消除了“红绿竞争”等影响检出精度的因素；系统采用帧频作为同步切换的总控信号，使ＣＲＴ的视页切换与液晶眼镜开关同步，为此而开发出的显示寄存器编程技术解决了ＣＲＴ视页切换的超高速要求。     

LOS三维立体内窥镜系统

ＬＯＳ三维立体内窥镜系统马跃中王晓坤空军４５１医院＊电视内窥镜手术是当前外科领域的新技术，然而，传统二维内窥镜系统只能观察物体的平面位置，操作难度高，安全系数低，使得该技术的普及受到限制。德国劳氏（ＬＯＳ）公司最新推出的三维立体内窥镜系统，使手术从平...     

基于立体视觉的手术导航光学定位系统

背景：以立体视觉技术为基础的手术导航定位系统可为医生实时显示手术器械相对于病灶部位的位置和方向,提高手术定位精度。 目的：利用双目立体视觉技术对手术持针器导航标志物进行立体定位。 方法：采用带阈值的重心法提取手术持针器导航标志物的球心特征,采用张氏平面标定法得到立体摄像机的内外参数,利用最小二乘法原理确定手术持针器导航标志物三维坐标,进而确定穿刺针相对于病灶部分的位置关系。 结果与结论：在现有的实验条件下,立体光学定位系统能够对手术用持针器标志物进行实时定位,且手术精度能够满足导航的需求。     

基于计算机视觉的早期乳腺癌放射治疗一体化摆位系统研究

目的研究一种基于计算机立体视觉的乳腺癌放射治疗摆位验证的方法,以减少在乳腺癌分次放射治疗中,由于多次摆位、体型变化等因素的影响造成肿瘤位置动态位移引起治疗误差。方法使用由双摄像机组成的计算机视觉系统,准确匹配出多个特征标记物在左右两摄像机采集的图像中的具体坐标,依据双目成像的基本原理计算出各标记物在胸腹部表面特征点的三维坐标值,构建出乳房及胸部体表的立体特征形状,以此来完成在分次放射治疗前摆位准确性的在线判定。在算法设计过程中,采用动态选择待匹配图像和局部搜索的策略,目标图像匹配精确。结果调试实验表明,系统能够准确提供各标记点的三维空间位置,并且能够做到实时性计算。结论基于计算机立体视觉的乳腺癌放射治疗摆位系统能够为放射治疗摆位提供一定的定位数据指导。     

虚拟环境的医学应用及其在微机上的实现

本文首先说明了虚拟环境技术的概念、特点，并对其关键技术一图形生成、立体显示等技术作了较全面的论述；其次文章给出了虚拟环境在医学等领域的几种应用；文章的最后给出了一个基于微机平台的医学虚拟环境生成及播放系统的具体实现。     

立体显示经穴的解剖结构

国内外对经穴解剖形态的研究一般采用：（1）层次解剖法;（2）断面解剖法;（3）穴位巨微、显微和超微解剖法;（4）数字化经穴形态显示法.层次解剖法可以获得穴位层次解剖结构,但难以保存解剖标本;断面解剖法可以获得针刺深度上的穴位平面解剖结构,标本可以长期保存以供研究,但只能在二维空间进行观察,系统性不强;巨微、显微和超微解剖法更注重局部的细节研究;数字化经穴形态显示法是以断面切割法配合计算机技术获得数字化立体穴位形态结构,缺点是无法保留解剖标本.为此,作者设计制作出一种立体显示经穴解剖结构的标本.     

CT仿真内镜与内镜下经蝶窦入路相关解剖结构显示情况的比较

目的　探讨CT仿真内镜（CT virtual endoscopy, CTVE）对经蝶入路相关解剖结构的显示情况,为CTVE在经蝶手术中的应用提供依据。 方法 15具血管灌注成人尸颅进行蝶窦的CTVE重建和内镜解剖,比较两者对解剖结构的显示情况。 结果 CTVE与内镜均能显示浅表的颈内动脉隆起、视神经管隆起、视神经管-颈内动脉隐窝、蝶窦开口、斜坡凹陷的三维解剖图像,两者间的显示率差异无统计学意义（P>0.05）。通过传输函数设计技术(Transfer functions)、动态调高观察阈值,CTVE能显示鞍底深部的颈内动脉及视神经管、模拟部分手术过程,与内镜解剖所见类似。 结论 CTVE能显示鞍底浅表及深部重要结构的三维解剖图像,可用于指导经蝶手术的术前计划的形成及术中定位。     

The effects of stereo shift angle,geometric magnification and display zoom on depth measurements in digital stereomammography

We are developing virtual three-dimensional (3-D) cursors for measuring depths in digital stereomammograms. We performed a study to investigate the effects of stereo shift angle, geometric magnification, and display zoom on the accuracy of depth measurements made with a virtual 3-D cursor. A phantom containing 50 low contrast fibrils at depths ranging from 1 to 11 mm was imaged with a full-field digital mammography system. Left- and right-eye images were generated at stereo shift angles of +/-3 degrees and +/-6 degrees, using either contact or 1.8x geometric magnification geometry. The images were viewed on a high-resolution stereoscopic display system in normal and 2x zoom mode. Observers viewed the images with stereo glasses and adjusted the depth of a cross-shaped virtual cursor to best match the perceived depth of each fibril. The results for two trained observers with excellent stereo acuity were nearly identical when viewing the same images. The average root mean square errors for the two observers were 1.2 mm (+/-3 degrees contact, no zoom), 1.3 mm (+/-3 degrees contact zoom), 0.8 mm (+/-6 degrees contact, no zoom), 0.6 mm (+/-6 degrees contact, zoom), 0.8 mm (+/-3 magnification, no zoom), 0.7 mm (+/-3 degrees magnification, zoom), and 0.2 mm (+/-6 degrees magnification, no zoom). One observer repeated the entire study for two additional fibril phantom configurations. Combining all the results, we found that for the contact geometry increasing the stereo shift angle from +/-3 degrees to +/-6 degrees improved the depth measurement accuracy by factors of about 1.2-4.0. Zooming did not provide observable improvement in the depth measurement accuracy; sometimes having no effect, sometimes improving the accuracy, and other times reducing the accuracy, with no general trends. Its effect is likely within experimental errors. However, the stereo effect was more readily visualized in the zoom mode. Geometric magnification improved the depth measurement accuracy. The best accuracy among all cases was about 0.2 mm, obtained with geometric magnification using a stereo angle of +/-6 degrees. This is the mode we recommend for obtaining accurate depth measurements with virtual cursors in stereomammograms.     

Compare Display Schemes for Lung Nodule CT Screening

This study investigated the relative efficiencies of a stereographic display and two monoscopic display schemes for detecting lung nodules in chest computed tomography (CT). The ultimate goal was to determine whether stereoscopic display provides advantages for visualization and interpretation of three-dimensional (3D) medical image datasets. A retrospective study that compared lung nodule detection performances achieved using three different schemes for displaying 3D CT data was conducted. The display modes included slice-by-slice, orthogonal maximum intensity projection (MIP), and stereoscopic display. One hundred lung-cancer screening CT examinations containing 647 nodules were interpreted by eight radiologists, in each of the display modes. Reading times and displayed slab thickness versus time were recorded, as well as the probability, location, and size for each detected nodule. Nodule detection performance was analyzed using the receiver operating characteristic method. The stereo display mode provided higher detection performance with a shorter interpretation time, as compared to the other display modes tested in the study, although the difference was not statistically significant. The analysis also showed that there was no difference in the patterns of displayed slab thickness versus time between the stereo and MIP display modes. Most radiologists preferred reading the 3D data at a slab thickness that corresponded to five CT slices. Our results indicate that stereo display has the potential to improve radiologists' performance for detecting lung nodules in CT datasets. The experience gained in conducting the study also strongly suggests that further benefits can be achieved through providing readers with additional functionality.     

基于SoC的医用内窥镜高清视频显示系统

目的 开发一种基于SoC的医用内窥镜高清视频显示系统,以满足高分辨率和高实时显示的要求.方法 使用CMOS摄像头采集视频数据.使用集成有双核ARM Crotex-A9处理器和FPGA的SoC芯片作为核心,利用SoC的HPS搭建嵌入式系统实现人机交互,利用FPGA实现视频数据的处理和缓存.使用ARM AMBA AXI总线桥接宽带系统连接HPS和FPGA,以实现缓存的视频数据经编码后在显示屏上的实时显示.结果 搭建了一个基于SoC的高清视频显示系统,实现了高清视频数据采集、处理及实时显示、视频冻结等功能.结论 结果表明该方案有效可行,并具有可定制性、可多次开发、视频显示实时性好等优点.     

Computer-enhanced stereoscopic vision in a head-mounted operating binocular

Based on the Varioscope, a commercially available head-mounted operating binocular, we have developed the Varioscope AR, a see through head-mounted display (HMD) for augmented reality visualization that seamlessly fits into the infrastructure of a surgical navigation system. We have assessed the extent to which stereoscopic visualization improves target localization in computer-aided surgery in a phantom study. In order to quantify the depth perception of a user aiming at a given target, we have designed a phantom simulating typical clinical situations in skull base surgery. Sixteen steel spheres were fixed at the base of a bony skull, and several typical craniotomies were applied. After having taken CT scans, the skull was filled with opaque jelly in order to simulate brain tissue. The positions of the spheres were registered using VISIT, a system for computer-aided surgical navigation. Then attempts were made to locate the steel spheres with a bayonet probe through the craniotomies using VISIT and the Varioscope AR as a stereoscopic display device. Localization of targets 4 mm in diameter using stereoscopic vision and additional visual cues indicating target proximity had a success rate (defined as a first-trial hit rate) of 87.5%. Using monoscopic vision and target proximity indication, the success rate was found to be 66.6%. Omission of visual hints on reaching a target yielded a success rate of 79.2% in the stereo case and 56.25% with monoscopic vision. Time requirements for localizing all 16 targets ranged from 7.5 min (stereo, with proximity cues) to 10 min (mono, without proximity cues). Navigation error is primarily governed by the accuracy of registration in the navigation system, whereas the HMD does not appear to influence localization significantly. We conclude that stereo vision is a valuable tool in augmented reality guided interventions.     

金黄地鼠甲状旁腺主细胞的计算机三维重建

目的：建立连续超薄切片计算机三维重建方法并显示甲状旁腺主细胞的立体形态。方法：应用连续超薄切片和透射电镜技术、计算机图像处理技术，用“金子塔异或指数方法”实现连续超薄切片图像对位，体积显示算法实验三维重建。结果：在Ｓｕｎ工作站中形象地从各个角度揭示了甲状旁腺主细胞内高尔基体、线粒体、细胞膜等结构的立体形态和空间毗邻关系。结论：连续超薄切片图像计算机三维重建方法能直观地显示甲状旁腺主细胞各细胞器的立体形态。     

内镜电动缝合器的设计与研究

目的设计一种内窥镜用电动缝合器,提高经内窥镜金属夹释放的自动化程度、便捷性和精准性。方法设计电动缝合器的机械结构,并完成样机制作,实现了内镜微创手术的电动驱动。搭建电控测试平台,利用位移传感器和脉冲数显器,测试电动控制系统的稳定性和准确性。试验证明,电动缝合器可以准确地完成抓取软组织和释放金属夹这一过程。结果对于实验所获得的数据,由Matlab进行三阶多项式拟合,得到在正反转和不同的转速下位移准确率均在2%以下。结论内镜电动缝合器的电控系统和机械结构可以满足内镜下微创手术中金属夹的推送和释放过程,有助于医生更加便捷,有效地实现消化道创口的闭合。     

人体器官的计算机三维重建及显示

本研究应用国内计算机的设备条件,采用体素表示的表面显示法,对人体肾脏、颅及腰椎的CT图象进行了计算机三维重建和显示。对新鲜离体肾脏标本先行包埋、低温冰冻,横断连续切割和撮影,然后再行轮廓描绘并将图象输入计算机;另外选择颅和腰椎横断面的CT图象,同样输入机内。在Vax-11/730主机,S-600图象处理系统下,用FORTRAN 77编制成软件包,实现在彩色监视器的屏幕上,对上述器官进行了三维重建和显示。重建后的器官可按需要进行不同角度的旋转、剖割和透明处理。图象逼真,富有立体感。本研究为解剖学的教学和科研,为CT诊断等提供了一种新颖的、有价值的显像手段。     

Effects of magnification and zooming on depth perception in digital stereomammography: an observer performance study

We are evaluating the application of stereoscopic imaging to digital mammography. In the current study, we investigated the effects of magnification and zooming on depth perception. A modular phantom was designed which contained six layers of 1-mm-thick Lexan plates, each spaced 1 mm apart. Eight to nine small, thin nylon fibrils were pasted on each plate in horizontal or vertical orientations such that they formed 25 crossing fibril pairs in a projected image. The depth separation between each fibril pair ranged from 2 to 10 mm. A change in the order of the Lexan plates changed the depth separation of the two fibrils in a pair. Stereoscopic image pairs of the phantom were acquired with a GE full-field digital mammography system. Three different phantom configurations were imaged. All images were obtained using a Rh target/Rh filter spectrum at 30 kVp tube potential and a +/- 3 stereo shift angle. Images were acquired in both contact and 1.8X magnification geometry and an exposure range of 4 to 63 mAs was employed. The images were displayed on a Barco monitor driven by a Metheus stereo graphics board and viewed with LCD stereo glasses. Five observers participated in the study. Each observer visually judged whether the vertical fibril was in front of or behind the horizontal fibril in each fibril pair. It was found that the accuracy of depth discrimination increased with increasing fibril depth separation and x-ray exposure. The accuracy was not improved by electronic display zooming of the contact stereo images by 2X. Under conditions of high noise (low mAs) and small depth separation between the fibrils, the observers' depth discrimination ability was significantly better in stereo images acquired with geometric magnification than in images acquired with a contact technique and displayed with or without zooming. Under our experimental conditions, a 2 mm depth discrimination was achieved with over 60% accuracy on contact images with and without zooming, and with over 90% accuracy on magnification images. This study indicates that stereoscopic imaging, especially with magnification, may be useful for visualizing the spatial distribution of microcalcifications in a cluster and for differentiating overlapping tissues from masses on mammograms.