定位模板在放射治疗中的应用

目的:探讨定位模板在放射治疗中应用体会。方法:以恶性淋巴瘤为例,放疗过程中应用定位模板进行定位、复位、摆位,同时和传统的方法进行比较。结果:使用定位模板定位、摆位可保证患者体位的重复性、减轻患者的疲乏程度、提高定位、摆位的精度及速度,减轻护理人员劳动强度。结论:正确使用定位模板,基本消除了人为的摆位误差,提高临床护理工作质量。     

胸部肿瘤患者放疗体位固定技术探讨

目的:探讨胸部肿瘤患者两种不同体位固定技术对提高治疗重复摆位精度的影响。方法:30例胸部肿瘤放疗患者随机分为两组,一组采用真空负压袋固定体位;另一组采用低温热塑体膜固定体位。分别在模拟定位机和电子直线加速器下拍摄模拟定位片和射野验证片,以模拟定位片上射野中心为坐标,测量并计算出两射野中心点在X轴、Y轴、Z轴上的重复摆位误差大小。结果:两组射野中心点在X轴方向上摆位误差分别为(1.37±1.31)mm和(1.35±1.29)mm(P>0.05)、Y轴方向上摆位误差分别为(1.33±1.14)mm和(1.26±1.12)mm(P>0.05)、Z轴方向上摆位误差分别为(2.17±1.54)mm和(1.47±1.32)mm(P<0.01)。结论:胸部肿瘤放射治疗采用热塑体膜固定技术有助于体位的固定,减少摆位误差,提高患者治疗摆位的精确度。     

盆腔肿瘤精确放射治疗摆位误差42例分析

目的：确定盆腔肿瘤精确放疗时的摆位误差。方法：采用医科达电子射野影像系统对42例盆腔肿瘤患者放疗前正侧位验证影像与CT定位影像重建的DRR影像进行比较,并且对患者的前后、左右和头足方向误差进行测量。结果：各方向的摆位误差分布均正常,盆腔部的摆位误差主要发生在患者前后和头足方向上。结论：利用医科达电子射野影像系统可以有效减少摆位的误差,提高摆位的精确性。     

CBCT图像引导下放射治疗的摆位误差分析

选择到我院进行诊治的20例癌症患者,利用瓦里安Trilogy加速器实施调强放射治疗,所选每一位患者在首次治疗前均实施一次CBCT扫描,而后在后续治疗期间每周进行一次扫描,接着和计划CT图像配准获得位移误差。所获图像共210幅。垂直方向、左右方向以及头脚方向误差分别为1.34±0.31mm、1.74±0.43mm、2.68±0.74mm;经纠正后,摆位误差减少,纠正前后差异明显(P0.05);治疗后各方向摆位误差和纠正后相比,所存差异不明显(P0.05)。CBCT应用于放射治疗中具有十分重要的作用,在放射治疗期间重复摆位必然会存在误差,对此,为确保靶区和附近正常组织器官剂量分布更加的准确,应及时对误差原因进行分析,且采取相应的措施予以处理,从而确保治疗效果。     

千伏极CBCT在食管癌调强放疗摆位中的应用

目的探讨图像引导放疗(IGRT)系统在食管癌调强放疗摆位修正的应用.方法应用医科达公司的synergy机载KV-CBCT对23例食管癌调强患者每次照射前获取X线容积图像(X-ray volumetric images,XVI)与计划CT图像及其靶中心进行匹配,获取X、Y、Z三个方向的误差,并分析纠正误差.结果23例患者均坚持完成放疗,共做了474次CBCT,其中治疗前320次,摆位误差在X(左右) Y(头脚)Z(前后)三个方向≥3mm,分别为(-0.04±4.63)、(0.07±9.69)、(-0.15±4.33)mm.结论千伏极CBCT在食管癌调强放疗摆位中可以提高等中心摆位精度,检测并调整摆位误差,有效减少放射野边界,减少并发症的发生.     

鼻咽癌精确治疗摆位误差分析

目的探讨鼻咽癌精确放射治疗过程中的摆位误差。方法应用电子射野影像系统（EPID）拍摄的验证片与计划系统所形成的数字重建射线影像（DRR）进行比较。结果3个方向的摆位误差平均值分别为X轴（左右方向）（1．15±0．4）mm,Y轴（头脚方向）（1．35±0．6）mm和Z轴（前后方向）（0．34±0．2）mm,摆位偏差主要发生在X、Y方向。所发生的误差在允许范围内,且治疗期间的摆位误差无显著差异。结论鼻咽癌精确放疗时采用头颈肩网膜体位固定技术,可提高摆位精度,确保治疗效果。     

两种不同固定技术在盆腔肿瘤体外放射治疗中摆位误差的比较

目的：比较两种不同固定技术在盆腔肿瘤体外放射治疗中摆位误差,进一步提高精确放射治疗的摆位精度。方法将接受体外放射治疗的64例盆腔肿瘤患者分为两组：A组应用俯卧位定位板;B组俯卧位定位板＋热塑体膜。各例病例分别在直线加速器的电子射野影像装置（EPID）下拍摄正、侧位射野验证片,与CT模拟定位图像重建的DRR图像进行比对,得出摆位位移数据。将A、B组摆位位移数据整理,分析出各组的摆位误差。结果 A、B组各方向摆位误差如下：左右（X轴）：（1.269±1.292）和（1.281±0.016）（P＜0.05）;头脚（Y轴）：（1.926±1.816）和（1.936±1.830）（P＞0.05）;腹背（Z轴）：（1.956±2.239）和（1.962±2.163）（P＞0.05）。结论在定期的EPID验证条件下,采用两种不同固定技术,单纯应用俯卧位定位板的固定技术在左右（X轴）方向上优于俯卧位定位板＋热塑体膜,而头脚（Y轴）方向、腹背（Z轴）方向上差异无统计学意义。     

精确量化指标在头颈部放射治疗重复摆位质量控制中的应用

目的研究量化指标在头颈部放射治疗重复摆位中的作用。方法将需同期放射治疗的头网膜固定和头颈肩网膜固定的患者随机分为两组,即常规方法与质量控制组。各组采用不同摆位方法,分别对其进行摆位时间、治疗后目测误差、计划系统验证误差的统计。结杲头网膜固定常规方法组治疗后患者体位移动的最大范围为2mm,与质量控制组组间无显著性差异（P〉0．05）;但计划系统验证头网膜固定患者的体位移动最大范围为15mm,与质量控制组组间有显著性差异（P〈0．01）。头颈肩网膜固定常规方法组治疗后患者体位移动的最大范围为6mm,与质量控制组组间有显著性差异（P〈0．01）;计划系统验证头颈肩网膜固定常规方法组患者的体位移动最大范围为10mm,与质量控制组组间有显著性差异（P〈0．01）。结论精确量化指标在重复摆位中起到了质量控制的作用,值得临床推广应用。     

不同体位固定方式对乳腺癌放疗摆位精度的影响

目的 分析不同体位固定方式对乳腺癌放疗摆位精度的影响。方法 选取 2020 年 1 月至 2021 年 10 月本院收治的接受放 射治疗的 110 例乳腺癌患者作为研究对象。按照抛币法将患者随机法分成观察组与对照组，每组 55 例。对照组采用体表标线固 定技术及个体化真空垫；观察组采用个体化形状记忆热塑网膜固定技术及真空固定垫。分析对比两组的首次摆位误差、线性摆 位误差通过率以及 CTV-PTV 外放间距。结果 两组在 Rz 轴、Rx 轴、Ry 轴、Y 轴首次摆位误差方面差异无统计学意义（P>0.05）， 但是在 Z 轴、X 轴的首次摆位误差，观察组均显著低于对照组（P<0.05）。观察组在 Y 轴、Z 轴、X 轴的线性摆位误差通过率 明显高于对照组（P<0.05）。观察组在 X 轴、Y 轴、Z 轴的 CTV-PTV 外放间距明显小于对照组（P<0.05）。结论 乳腺癌体位固 定时使用个体化真空固定垫与记忆型热塑网状体膜进行固定，能减少首次摆位误差，提高线性摆位误差通过率以及降低 CTV-PTV 外放间距。     

图像引导放射治疗技术提高腹部肿瘤放射治疗精度的临床研究

目的研究图像引导放射治疗技术提高腹部肿瘤放射治疗精度的效果。方法选择2017年10月-2018年11月的12例腹部肿瘤患者作为研究对象,用锥形束CT影像技术或者患者左右(x)、头脚(y)以及前后(z)的线性摆位误差,分析获得的摆位误差。结果对本次研究的10例患者分别进行30次锥形束CT检查,x、y、z的自由度误差用系统误差±随机误差表示,其中y方向的摆位误差最大,x方向的摆位误差最小。结论图像引导放射技术可以有效提高腹部肿瘤治疗的精度,值得推广。     

Segmentation in Echocardiographic Sequences using Shape-based Snake Model Combined with Generalized Hough Transformation

A novel method for segmentation of cardiac structures in temporal echocardiographic sequences based on the snake model is presented. The method is motivated by the observation that the structures of neighboring frames have consistent locations and shapes that aid in segmentation. To cooperate with the constraining information provided by the neighboring frames, we combine the template matching with the conventional snake model. It means that the model not only is driven by conventional internal and external forces, but also combines an additional constraint, the matching degree to measure the similarity between the neighboring prior shape and the derived contour. Furthermore, in order to auto or semi-automatically segment the sequent images without manually drawing the initial contours in each image, generalized Hough transformation (GHT) is used to roughly estimate the initial contour by transforming the neighboring prior shape. The method is particularly useful in case of the large frame-to-frame displacement of structure such as mitral valve. As a result, the active contour can easily detect the desirable boundaries in ultrasound images and has a high penetrability through the interference of various undesirables, such as the speckle, the tissue-related textures and the artifacts.     

实时手部精细运动意图识别方法的研究

目的:利用脑卒中患者的自主运动意识进行主动神经康复是促进患者脑功能重塑、提高康复训练效果的重要工程学手段。针对脑卒中患者手部精细运动功能恢复速度慢、恢复程度有限等问题,本文提出了一种基于数据手套的模板匹配方法,用于识别患者的手部精细运动意图。方法:利用自主研发的虚拟现实康复训练平台,将基于数据手套模板匹配的运动意图识别方法嵌入其中,并与基于表面肌电模式识别方法进行对比研究。招募了6例健康受试者参与实验,对16个手部精细动作的离线识别性能和实时识别性能分别进行分析,并对离线性能指标与实时性能指标之间的关系进行相关性研究。结果:采用基于数据手套模板匹配方法取得的平均离线动作识别准确率为95.00%±3.66%,平均实时动作完成率为91.31%±1.17%,显著高于基于表面肌电模式识别方法的离线动作识别准确率(84.66%±4.66%,P0.01)与实时动作完成率(71.86%±10.04%,P0.01)。另外,基于数据手套模板匹配方法取得的离线动作识别准确率与实时动作完成率是线性相关的(P0.05),而基于表面肌电模式识别方法取得的离线与实时性能指标不存在线性关系(P=0.4005)。结论:与传统的肌电模式识别方法相比,基于数据手套模板匹配方法具有显著的比较性优势。因此,有望成为手部精细运动功能主动神经康复中的一种有效的运动意图识别方法。     

A self-calibrating approach for the segmentation of retinal vessels by template matching and contour reconstruction

The automated processing of retinal images is a widely researched area in medical image analysis. Screening systems based on the automated and accurate recognition of retinopathies enable the earlier diagnosis of diseases like diabetic retinopathy, hypertension and their complications. The segmentation of the vascular system is a crucial task in the field: on the one hand, the accurate extraction of the vessel pixels aids the detection of other anatomical parts (like the optic disc Hoover and Goldbaum, 2003) and lesions (like microaneurysms Sopharak et al., 2013); on the other hand, the geometrical features of the vascular system and their temporal changes are shown to be related to diseases, like the vessel tortuosity to Fabry disease Sodi et al., 2013 and the arteriolar-to-venus (A/V) ratio to hypertension (Pakter et al., 2005).In this study, a novel technique based on template matching and contour reconstruction is proposed for the segmentation of the vasculature. In the template matching step generalized Gabor function based templates are used to extract the center lines of vessels. Then, the intensity characteristics of vessel contours measured in training databases are reconstructed. The method was trained and tested on two publicly available databases, DRIVE and STARE; and reached an average accuracy of 0.9494 and 0.9610, respectively. We have also carried out cross-database tests and found that the accuracy scores are higher than that of any previous technique trained and tested on the same database.     

Alternate site right ventricular pacing: defining template scoring

Background: Prolonged right ventricular (RV) apical pacing produces dysynchronous ventricular contraction, which may result in left ventricular (LV) dysfunction, whereas septal pacing sites might reflect a more synchronous LV activation. This study examined a method of evaluating alternate RV pacing sites using a template scoring system based on measuring the angle of lead attachment in the 40^o left anterior oblique (LAO) fluoroscopic view and its effect on altering the loop of lead in the RV. Methods: Twenty‐three consecutive patients for RV pacing were enrolled. Conventional active fixation leads were positioned in either the RV outflow tract (RVOT) or mid RV using a stylet designed for septal placement (Model 4140, St. Jude Medical, St. Paul, MN, USA). Using LAO cine fluoroscopy, a generous loop of lead was inserted into the RV chamber and the change in angle of attachment determined. Results: Successful positioning of pacing leads at the RVOT septum (18 patients) and mid‐RV septum (five patients) was achieved. With introduction of more lead into the RV chamber, the angle of attachment in the LAO projection altered over a range of 6^o–32^o for all patients with a mean of 14.6 ± 6.6^o. In 87% of patients, the range was predominantly within the same template score with only minor overlap into another zone. Conclusions: This study shows that the angle of lead attachment in the RV is altered by introducing more lead, but in most cases, the template score remains the same. Further studies are required to determine the accuracy and efficacy of the templates. (PACE 2011; 34:1080–1086)     

A semi-automatic method to determine electrode positions and labels from gel artifacts in EEG/fMRI-studies

The analysis of simultaneous EEG and fMRI data is generally based on the extraction of regressors of interest from the EEG, which are correlated to the fMRI data in a general linear model setting. In more advanced approaches, the spatial information of EEG is also exploited by assuming underlying dipole models. In this study, we present a semi automatic and efficient method to determine electrode positions from electrode gel artifacts, facilitating the integration of EEG and fMRI in future EEG/fMRI data models.In order to visualize all electrode artifacts simultaneously in a single view, a surface rendering of the structural MRI is made using a skin triangular mesh model as reference surface, which is expanded to a “pancake view”. Then the electrodes are determined with a simple mouse click for each electrode. Using the geometry of the skin surface and its transformation to the pancake view, the 3D coordinates of the electrodes are reconstructed in the MRI coordinate frame.The electrode labels are attached to the electrode positions by fitting a template grid of the electrode cap in which the labels are known. The correspondence problem between template and sample electrodes is solved by minimizing a cost function over rotations, shifts and scalings of the template grid. The crucial step here is to use the solution of the so-called “Hungarian algorithm” as a cost function, which makes it possible to identify the electrode artifacts in arbitrary order. The template electrode grid has to be constructed only once for each cap configuration.In our implementation of this method, the whole procedure can be performed within 15 min including import of MRI, surface reconstruction and transformation, electrode identification and fitting to template. The method is robust in the sense that an electrode template created for one subject can be used without identification errors for another subject for whom the same EEG cap was used. Furthermore, the method appears to be robust against spurious or missing artifacts. We therefore consider the proposed method as a useful and reliable tool within the larger toolbox required for the analysis of co-registered EEG/fMRI data.     

Augmented reality based real-time subcutaneous vein imaging system

A novel 3D reconstruction and fast imaging system for subcutaneous veins by augmented reality is presented. The study was performed to reduce the failure rate and time required in intravenous injection by providing augmented vein structures that back-project superimposed veins on the skin surface of the hand. Images of the subcutaneous vein are captured by two industrial cameras with extra reflective near-infrared lights. The veins are then segmented by a multiple-feature clustering method. Vein structures captured by the two cameras are matched and reconstructed based on the epipolar constraint and homographic property. The skin surface is reconstructed by active structured light with spatial encoding values and fusion displayed with the reconstructed vein. The vein and skin surface are both reconstructed in the 3D space. Results show that the structures can be precisely back-projected to the back of the hand for further augmented display and visualization. The overall system performance is evaluated in terms of vein segmentation, accuracy of vein matching, feature points distance error, duration times, accuracy of skin reconstruction, and augmented display. All experiments are validated with sets of real vein data. The imaging and augmented system produces good imaging and augmented reality results with high speed.OCIS codes: (110.0110) Imaging systems, (110.3080) Infrared imaging, (170.0110) Imaging systems, (100.0100) Image processing, (100.3010) Image reconstruction techniques     

数字及逆向工程技术在复杂骨科应用进展

背景：医学数据可视化技术的快速发展及不断对医学领域地渗透,尤其使脊柱外科在诊断和治疗上发生了根本性地改变,朝着＂精确化、个性化、微创化＂方向发展,已成为临床骨科治疗中不可或缺的重要手段。目的：通过对数字技术在复杂骨科应用进展,明确研究突破口。方法：由第一作者在PubMed数据库、万方数据库、维普数据、中国知网库检索,时间范围为1990/2011。检索词为＂个性化的定位导航模板,数字解剖模型,螺钉内固定术,逆向工程技术,快速成型技术＂。纳入标准为导航模板制备工艺及技术的研究、有限元相关理论的研究、实验及临床应用。排除标准为与此文目的无关、较陈旧的文献和重复同类研究。结果与结论：利用数字化技术重建的导航模板为骨科螺钉内固定的定位、定向固定提供了一种新的方法。通过数字化重建技术可以制作个体化导航模板,将模板紧密贴合于相应的解剖结构上进行导航穿刺,即可完成对术区的准确定位和定向。对复杂骨科手术,尤其是解剖结构畸形变的患者有着不可替代的意义。为临床手术设计奠定良好的基础,提高准确性和安全性。     

应用以修复为中心的简易种植模板种植牙159例临床回顾

目的总结评价以修复为中心的简易种植模板种植牙的临床疗效。方法选取2008~2012年种植科种植修复治疗患者159例,术前在模型上用直径2.0 mm蜡线确定植体位置方向,然后铺自凝塑料制作带有植入道的模板,术中应用模板指导手术,术后通过X线片检查及修复时在模型上观察基台的位置方向以检验种植体的三维位置方向是否合适。结果 268枚植体的位置、方向比较理想,均达到术前设计。修复后随访检查并进行满意度调查,159例患者中,156例对修复效果感觉满意,2例重新修复后感觉满意,1例对修复效果表示勉强可以接受。结论以修复为中心的简易种植模板对牙种植手术引导效果好,能准确地确定种植体的位置方向,为种植后期修复创造了良好的条件,对种植远期成功率提供了有力的保障,患者主观感觉舒适、咀嚼效率高,对种植手术接纳程度高,利于种植手术的普及。     

RABBIT: Rapid alignment of brains by building intermediate templates

A brain image registration algorithm, referred to as RABBIT, is proposed to achieve fast and accurate image registration with the help of an intermediate template generated by a statistical deformation model. The statistical deformation model is built by principal component analysis (PCA) on a set of training samples of brain deformation fields that warp a selected template image to the individual brain samples. The statistical deformation model is capable of characterizing individual brain deformations by a small number of parameters, which is used to rapidly estimate the brain deformation between the template and a new individual brain image. The estimated deformation is then used to warp the template, thus generating an intermediate template close to the individual brain image. Finally, the shape difference between the intermediate template and the individual brain is estimated by an image registration algorithm, e.g., HAMMER. The overall registration between the template and the individual brain image can be achieved by directly combining the deformation fields that warp the template to the intermediate template, and the intermediate template to the individual brain image. The algorithm has been validated for spatial normalization of both simulated and real magnetic resonance imaging (MRI) brain images. Compared with HAMMER, the experimental results demonstrate that the proposed algorithm can achieve over five times speedup, with similar registration accuracy and statistical power in detecting brain atrophy.     

临床护理记录电子模板的开发与应用

目的研究护理记录电子模板在临床应用的可行性,为提高护理文书质量提供保证。方法按照《病历书写基本规范(试行)》的要求,在计算机上开发护理记录模板,套入"军字1号"病程记录续版进行临床护理记录书写。结果提高了工作效率,且操作简单快捷,护理文书质量明显提高。结论护理记录电子模板在临床应用具有可行性,能促进我国护理信息化发展的进程。