快速成型技术在医学中的应用

快速成型是20世纪80年代末发展起来的新技术,它在医学上已得到广泛应用,本对快速成型进行了简单介绍,主要综述了在手术计划,假体制造和生物工程中的应用;对某些领域中的不足也进行了讨论,主要是相对于工业快速成型技术可达到的精度,医学CT扫描的层距显得过厚。     

快速成型技术原理及其医学应用

随着社会需要和科学技术的发展,产品更新的周期越来越短,因而要求设计者不但能根据市场的要求很快地设计新产品,而且能在尽可能短的时间内制造出产品,进行必要的性能测试,征求用户的意见,并进行修改,最后形成能投放市场的定型产品.     

快速成型技术在骨科的应用研究进展

快速成型技术是20世纪80年代中期发展起来的,它是在计算机控制下,根据物体的CAD模型或CT等数据,不借助其他设备,通过材料的精确堆积,制造原型的一种基于离散、堆积成型原理的新的数字化成型技术;近年来通过与螺旋CT或核磁共振等检测手段的三维图像重建功能相结合,在骨科领域显示出良好的应用前景。综述了该技术在骨科领域内的器官模型制备和手术策划、个体化假体制备、骨组织工程多孔支架制备等主要应用方向的研究进展。     

快速成型技术原理及其医学应用

随着社会需要和科学技术的发展，产品更新的周期越来越短，因而要求设计者不但能根据市场的要求很快地设计新产品，而且能在尽可能短的时间内制造出产品，进行必要的性能测试，征求用户的意见，并进行修改，最后形成能投放市场的定型产品。用传统方法制作样品时，需采用多种机械加工机床，以及相应的工具和模具，既费时，又成本高。为克服上述问题，近几年来出现了快速成型技术和快速成型系统。     

快速成型技术在正颌外科中的应用

目的利用螺旋CT扫描、三维重建和快速成型技术制作三维头颅模型,并探讨其在口腔颌面部治疗中应用的可行性与准确性。方法对1例颅骨和口腔颌面部不对称严重畸形的第一、二鳃弓综合症患者使用螺旋CT连续薄层容积扫描,CT数据传至工作站后行三维重建并转换成STL文件格式。将处理后的数据输入快速成型机制造三维头颅模型,在此模型上直接进行测量,并利用患者健侧下颌骨镜像复制出其患侧下颌。结果根据CT数据制作的三维模型能立体、精确地显示颅面三维解剖结构及其相互关系。模型与真实个体之间总体误差可以控制在0．02～0．53mm。通过镜像复制出患侧下颌骨模型。为准确了解畸形情况、制定合理的手术治疗计划提供了极为重要的依据。结论快速成型技术制作颅骨镜像实体模型可行。     

基于水平集的快速成型技术在颅骨缺损修复中的应用

目的 探索利用水平集方法和快速原型技术得到颅骨缺损修复假体用于颅骨修复。方法 基于有颅骨缺损的患者的CT数据,利用水平集方法结合病人脑组织信息得到完整的颅骨原始轮廓,还原出颅骨缺损部位信息,三维重建后应用三维打印机进行定制的颅骨缺损修复假体的快速原型制造。结果 所得颅骨缺损修复假体非常适合颅骨缺损的部位,使用水平集方法和快速原型技术得到的颅骨缺损修复假体有很好的个体适配性。结论 水平集方法和快速原型技术精确制造颅骨缺损修复假体是可行的,对颅骨缺损修复手术提供术前规划、减少术中危害具有重要意义。     

快速成型技术在人工骨制造过程中的应用研究

通过对快速成型技术原理的介绍和对国内外 RP 技术在人工骨制造过程中的研究现状及实际应用的描述。探讨快速成型技术(RP)在人工骨制造领域的应用价值。提出了此研究领域存在的问题和发展方向。证明快速成型技术在人工骨制造领域具有很好发展前景。     

计算机快速成型技术在复杂重度脊柱侧凸畸形中的初步临床应用

目的采用计算机快速成型技术重建复杂重度脊柱侧凸畸形模型，探讨其在临床矫形手术中的初步临床应用价值：方法26例重度复杂脊柱侧凸畸形患者，平均年龄21．8岁（6～54岁），其中男性5例，女性21例。特发性脊柱侧凸4例，先天性脊柱侧凸20例，神经肌肉型脊柱侧凸2例。病程6～45年，平均19.3年。采用手术治疗，术前根据CT断层扫描数据进行计算机快速成型，将重建的脊柱侧凸畸形模型应用于临床。结果根据重建的脊柱侧凸畸形模型制定手术计划和进行手术设计，术中所见脊柱畸形与计算机重建模型的外形尺寸完全一致，消毒后可在手术台上直接指导手术操作。26例患者按计划完成矫形手术，矫形效果和内固定满意，未出现神经、血管损伤等并发症。结论计算机快速成型技术重建复杂重度脊柱侧凸畸形模型能够精确和直观地反映脊柱畸形情况，从而指导制定手术计划和手术操作。     

应用快速成型技术重建人工颅骨

应用CAD/CAM技术和快速成型技术,建立个性化设计、制造人工颅骨的快速响应体系.通过螺旋CT扫描、CAD三维重建成像、三种快速成型工艺,制成与患者颅骨缺损部位几何形态相同的个性化实体模型,应用翻模工艺和EH复合型生物活性人工骨材料,制成患者骨修复治疗用颅骨.结果显示人工颅骨几何外形与骨缺损部位非常吻合,与健康侧对称,临床效果非常满意.三种快速成型工艺中,选择性激光烧结法工艺较适合于个性化实体模型制作.完成整个制作流程的最快时间为2d.应用快速成型技术重建颅骨制作系统为颅骨缺损患者提供了一种可有效提高临床治疗效果和修复美学效果的新技术.     

影像实物建模的医学应用价值与局限

评估基于快速成型技术的影像实物建模在医学中的应用价值,并讨论其进一步应用增长的限制因素与未来前景。     

快速原型技术在颅颌面整复中的应用

快速原型(rapidprototyping,RP)技术作为一种全新的成形制造技术,具有多方面的优越性和适用性,已深入到医学领域的诸多学科,其中颅颌面整复方面的研究更显活跃。概括介绍快速原型技术及其在颅颌面整复方面的研究近况并展望其应用前景。     

New layer-based imaging and rapid prototyping techniques for computer-aided design and manufacture of custom dental restoration

Fixed dental restoration by conventional methods greatly relies on the skill and experience of the dental technician. The quality and accuracy of the final product depends mostly on the technician's subjective judgment. In addition, the traditional manual operation involves many complex procedures, and is a time-consuming and labour-intensive job. Most importantly, no quantitative design and manufacturing information is preserved for future retrieval. In this paper, a new device for scanning the dental profile and reconstructing 3D digital information of a dental model based on a layer-based imaging technique, called abrasive computer tomography (ACT) was designed in-house and proposed for the design of custom dental restoration. The fixed partial dental restoration was then produced by rapid prototyping (RP) and computer numerical control (CNC) machining methods based on the ACT scanned digital information. A force feedback sculptor (FreeForm system, Sensible Technologies, Inc., Cambridge MA, USA), which comprises 3D Touch technology, was applied to modify the morphology and design of the fixed dental restoration. In addition, a comparison of conventional manual operation and digital manufacture using both RP and CNC machining technologies for fixed dental restoration production is presented. Finally, a digital custom fixed restoration manufacturing protocol integrating proposed layer-based dental profile scanning, computer-aided design, 3D force feedback feature modification and advanced fixed restoration manufacturing techniques is illustrated. The proposed method provides solid evidence that computer-aided design and manufacturing technologies may become a new avenue for custom-made fixed restoration design, analysis, and production in the 21st century.     

快速成型方法制备组织工程支架的研究与应用

背景：快速成型是基于材料堆积法,结合计算机、数控、激光和材料技术于一体的高新制造技术。 目的：综述快速成型技术在组织工程支架制备中的应用。 方法：由第一作者检索万方数据库、中国知网数据库和Elsevier Science Direct Online有关支架材料的生物力学性能、支架材料发展前景及快速成型技术在支架材料制备领域中应用研究等方面的文献。 结果与结论：快速成型技术应用于组织工程支架的制备已经越来越成熟,快速成型技术不但克服了传统制造方法中存在的支架复杂外形制造困难和内部微结构无法控制的缺陷,而且还可以通过有限元分析预先对支架的结构进行优化,以实现改善支架机械强度等某些特殊的要求。但是,由于组织器官的特殊性和排外性及细胞的黏附条件,不但要从结构上改善支架,而且需要快速成型技术与具有组织相容性及可降解的材料相结合,使支架植入生物体后,细胞能更好地增殖和分化,促进组织再生,修复缺损组织。     

New Materials for Rapid Prototyping Applications

Summary: Rapid prototyping (RP) is a widely used manufacturing tool in the product development cycle. This Highlight article gives a brief overview of the currently available RP techniques with special emphasis on three‐dimensional (3D) printing. The advantages and drawbacks of various RP processes regarding material quality, feature resolution, and surface quality are pointed out. New developments in the field of material development allow the use of polymer ionomers for 3D printing. Using polymer ionomers some of the drawbacks of 3D printing can be eliminated. In particular, the mechanical strength can be increased compared to traditional powder systems used for 3D printing. This article describes the chemical background of polymer ionomers and the relevance of these materials for future developments in RP.

Cellular structures made of photopolymerizable polymers.     

Three-dimensional reconstruction and rapid prototyping of femur bone using multiple digital X-rays

The medical industry has made great strides in offering healthcare services, and rapid prototyping (RP) is an example of a tool that has experienced tremendous growth in the medical field. RP technologies are used for building models that provide visual and tactile information. The linking of scanning technology and RP technologies now permit anatomical image data to be viewed in a completely different manner. The feasibility of producing RP models using digital X-rays is explained in this work. Digital X-rays taken at regular angular intervals of the anatomical object are used as input data to reconstruct the anatomical object. Software to detect the edge of the bone projection and export it to two-dimensional coordinates was developed using Visual Basic 6.0. This coordinate data of the image is used for creating the spline of the two-dimensional projections of the bone. Then, using extrusion and Boolean intersection operations, the three-dimensional model of the bone without concavities is reconstructed. In order to incorporate the concavities, a unique method is applied. Using grey-level histograms, the concavities are detected, and using subtraction Boolean operation the concavities are incorporated in the model. The CAD model obtained is converted to stl file format, which is the defacto standard for RP. Using FDM 2000 machine the prototype of the bone is fabricated. The reconstructed model is compared with the CT model of the actual bone. The CT model and X-ray model are compared using the slices taken with a constant inter-slice distance. The fabricated bone model is used as visual-tactile representation, surgical planning and simulation tool for doctors. This would enhance the doctor – patient relationship and reduce the time for surgery.     

New layer-based imaging and rapid prototyping techniques for computer-aided design and manufacture of custom dental restoration

Fixed dental restoration by conventional methods greatly relies on the skill and experience of the dental technician. The quality and accuracy of the final product depends mostly on the technician's subjective judgment. In addition, the traditional manual operation involves many complex procedures, and is a time-consuming and labour-intensive job. Most importantly, no quantitative design and manufacturing information is preserved for future retrieval. In this paper, a new device for scanning the dental profile and reconstructing 3D digital information of a dental model based on a layer-based imaging technique, called abrasive computer tomography (ACT) was designed in-house and proposed for the design of custom dental restoration. The fixed partial dental restoration was then produced by rapid prototyping (RP) and computer numerical control (CNC) machining methods based on the ACT scanned digital information. A force feedback sculptor (FreeForm system, Sensible Technologies, Inc., Cambridge MA, USA), which comprises 3D Touch technology, was applied to modify the morphology and design of the fixed dental restoration. In addition, a comparison of conventional manual operation and digital manufacture using both RP and CNC machining technologies for fixed dental restoration production is presented. Finally, a digital custom fixed restoration manufacturing protocol integrating proposed layer-based dental profile scanning, computer-aided design, 3D force feedback feature modification and advanced fixed restoration manufacturing techniques is illustrated. The proposed method provides solid evidence that computer-aided design and manufacturing technologies may become a new avenue for custom-made fixed restoration design, analysis, and production in the 21st century.     

Virtual topological optimisation of scaffolds for rapid prototyping

Advanced additive techniques are now being developed to fabricate scaffolds with controlled architecture for tissue engineering. These techniques combine computer-aided design (CAD) with computer-aided manufacturing (CAM) tools to produce three-dimensional structures layer by layer in a multitude of materials. Actual prediction of the effective mechanical properties of scaffolds produced by additive technologies, is very important for tissue engineering applications. A novel computer based technique for scaffold design is topological optimisation. Topological optimisation is a form of “shape” optimisation, usually referred to as “layout” optimisation. The goal of topological optimisation is to find the best use of material for a body that is subjected to either a single load or a multiple load distribution. This paper proposes a topological optimisation scheme in order to obtain the ideal topological architectures of scaffolds, maximising its mechanical behaviour.     

Malaria rapid diagnostic tests in travel medicine

Malaria is a serious condition in the non-immune traveller, and prognosis depends on timely diagnosis. Although microscopy remains the cornerstone of diagnosis, malaria rapid diagnostic tests (RDTs) are increasingly used in non-endemic settings. They are easy to use, provide results rapidly and require no specific training and equipment. Reported sensitivities vary between different RDT products but are generally good for Plasmodium falciparum, with RDTs detecting the P. falciparum antigen histidine-rich protein-2 (PfHRP2) scoring slightly better than P. falciparumlactate dehydrogenase (Pf-pLDH)-detecting RDTs. Sensitivity is lower for Plasmodium vivax (66.0 – 88.0%) and poor for Plasmodium ovale (5.5 – 86.7%) and Plasmodium malariae (21.4 – 45.2%). Rapid diagnostic tests have several other limitations, including persistence of the PfHRP2 antigen, cross-reactions of P. falciparum with the non-falciparum test line and vice versa and (rare) false-positive reactions due to other infectious agents or immunological factors. False-negative results occur in the case of low parasite densities, prozone effect or pfhrp2 gene deletions. In addition, errors in interpretation occur, partly due to inadequacies in the instructions for use. Finally, RDTs do not give information about parasite density. In the diagnostic laboratory, RDTs are a valuable adjunct to (but not a replacement for) microscopy for the diagnosis of malaria in the returned traveller.In malaria endemic settings, special groups of travellers (those travelling for long periods, expatriates and short-stay frequent travellers) who are remote from qualified medical services may benefit from self-diagnosis by RDTs, provided they use correctly stored RDT products of proven accuracy, with comprehensive instructions for use and appropriate hands-on training.