Primer on Medical Imaging

During the last weeks of 1895, Wilhelm Roentgen performed numerous experiments to characterize the new kind of rays he had serendipitously discovered. One of the most striking results of these experiments, an image of the bones in his wife's hand, demonstrated how the properties of X-rays could be harnessed to create pictures of internal bony anatomy. A new era in medicine had arrived. X-ray imaging, or radiography, quickly became an important tool for physicians. During the decades after its...

Overview

While rapid prototyping (RP) technology has primarily been developed for the manufacturing industry to assist in speeding up the development of new products, its vendors and users were quick to realize the technology was also suitable for applications in the medical field. Doctors and surgeons have always been looking for better ways to describe, understand and diagnose the condition of individual patients. Diagnostic tools have become increasingly more sophisticated and the latest CT, MRI and...

Info

Figure 6.2 BioBuild can load raw image data, allowing the user to enter any missing volume properties Data can also be loaded from a remote DICOM server, using the DICOM medical imaging network protocol. Remote server access is easily configured for any number of servers, as highlighted in Figure 6.3. Many hospitals now use the DICOM standard for storage and transmission of patient data from multiple imaging modalities, and BioBuild is able to access these patient data seamlessly across the...

Systems Based on Extrusion Direct Writing

A number of groups (Sun and Lal, 2002 Sachlos et al., 2003 Hutmacher, Sittinger and Risbud, 2004) and companies (http www.envisiontec.de, http www.Sciperio.com) have developed SFF machines that can perform extrusion of strands filaments and or plotting of dots in 3D (Figure 8.5). These systems are built to make use of a wide variety of polymer hot melts as well as pastes slurries (Calvert et al., 1998 Cesarano and Calvert, 2000 Calvert and Crockett 1997), solutions (Ang et al., 2002) and...

Threedimensional printing 3DP

The 3DP technology was developed at the Massachusetts Institute of Technology (MIT) (Cima et al., 1995). 3DP is used to create a solid object by ink-jet printing a binder into selected areas of sequentially deposited layers of powder. Each layer is created by spreading a thin layer of powder over the surface of a powder bed. The powder bed is supported by a piston which descends upon powder spreading and printing of each layer (or, conversely, the ink jets and spreader are raised after printing...

Indirect SFF

There are two principal routes for the fabrication of scaffolds by RP indirect and direct routes. Indirect routes rely on an additional moulding step after fabricating the master pattern by RP. The term 'indirect' SFF was coined for scaffold fabrication by Hollister's group (Chu et al., 2002 Hollister, Maddox and Taboas, 2002 Hollister et al., 2000 Hollister, et al., 2001 Taboas et al., 2003). His group used the lost mould technique, combining the epoxy resin moulds made by SLA (SL 5170 and SLA...

Edited by Ian Gibson

Department of Mechanical Engineering University of Hong Kong Hong Kong Copyright 2005 John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England Email (for orders and customer service enquiries) cs-books wiley.co.uk Visit our Home Page on www.wiley.com All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or...

Medical Scan Process

There are many 3D scan techniques that have been used in medical applications. Computed tomography (CT), magnetic resonance imaging (MRI), ultrasonic imaging and 3D laser scanning are the most commonly used. The medical scan process consists of a scan phase and a reconstruction phase. The 3D scan phase captures the raw data and generates the initial geometry data, usually as a 2D boundary object or a 3D point cloud. The 3D reconstruction phase is the internal processing of these data into...

Case Study

Rapid Prototyping Implants

4.5.1 Case study with CT MR scanned data The following case depicts a typical medical scan process from scan phase to 3D data reconstruction phase. A skull of a patient was chosen. Part of the patient's skull was removed by surgery. A biocompatible tissue part needed to be produced to fill in the hole and help the patient to heal the region again. The image processing segmentation was performed using tools provided by the Materialise software package MIMCS and CTM module. Mimics is a fully...

References

A. and Heckman, J. D. 1997 Biodegradable PLA-PGA polymers for tissue engineering in orthopedics. Mater. Sci. Forum, 250, 115-28. Ang, T. H. et al. 2002 Fabrication of 3D chitosan-hydroxyapatite scaffolds using a robotic dispensing system. Mater. Sci. Eng. C, 20, 35-42. Bao, L. R., Cheng, X., Huang, X. D. et al. 2002 Nanoimprinting over topography and multilayer three-dimensional printing. J. Vacuum Sci. and Technol. B, November-December, 20 6 , 2881-6. Beaman, J....

Process of making the belowknee artificial prosthesis

The process first involves soaking a bandage in water and plaster of Paris, and then wrapping the layer of bandage around the stump of the patient to obtain its shape. The bandage plaster composition is then allowed to harden. The hardened socket is removed from the stump and used as a negative mould. Plaster of Paris is poured into the negative mould. Some time is again allowed for the plaster to harden before the negative mould is cut open to extract the positive mould within. Finally, the...

Custom joint replacement implants

Rapid Prototyping Implants

Keenan et al. 5 reported on seven cases where patients suffered from supracondylar fractures above their total knee arthroplasties. This is a very serious complication that can occur immediately after the primary joint replacement or many years down the road. When the distal femur fractures right above the femoral component, it is very difficult for the surgeon to reattach the bone and get a stable fixation. In these seven cases, the surgeons decided to use custom designed long-stem...

Custom bone plates and implants

Bone Plate Cad Model

While the previous section discussed several studies involving the custom design of joint replacement implants, work has also been done in the area of custom bone plates. Van Steenberghe et al. 16 investigated the use of custom-designed drill guides for the placement of zygoma implants. Without the drill guides, it is quite difficult to obtain precise hole locations. Although a CT-based computer planning system is available to assist in determining where the holes should be located,...

Selective laser sintering SLS

SLS also uses a focused laser beam, but to sinter areas of a loosely compacted powder. In this method, a thin layer of powder is spread evenly onto a flat surface with a roller mechanism. The powder is then raster scanned with a high-power laser beam. The powder material that is struck by the laser beam is fused, while the other areas of powder remain dissociated. Successive layers of powder are deposited and raster scanned, one on top of another, until an entire part is complete. Each layer is...

Computer Approach in Dental Implantology

Surgiguide

Materialise is market leader in oral implantology simulation software. Implant placement and surgery simulation packages offer increased opportunities for developing state-of-the-art techniques for minimally invasive procedures. SimPlant software, a software for 3D modelling and interactive 3D-based implant planning, makes it possible to create a complete planning environment from CT scanning images by reformatting of the dataset cross-sections, panoramic image and 3D visualization. The...

Electron Beam Melting Technology

After a custom implant is designed, the next step is to fabricate the device in an appropriate material. CNC machining from bar stock is a common fabrication method for custom implants. Since custom components have complex geometric shapes, a five-axis CNC machine is usually needed to do the fabrication. Generating five-axis CNC toolpaths is quite complicated, and fixturing complex shapes during multiple set ups requires considerable skill and experience. Once the toolpath is generated, the...

Contributors

Medical Modeling LLC, 17301 West Colfax Avenue, Suite 300, Golden, Email information medicalmodeling.com Dr. Denis Cormier, Associate Professor Department of Industrial Engineering, North Carolina State University, Raleigh, North Carolina 27695-7906, USA Email cormier ncsu.edu Materialise, Technolgielaan 15, 3001 Leuven, Belgium Email Advanced Manufacturing Technology for Medical Applications Edited by I. Gibson 2006 John Wiley amp Sons, Ltd. Paul D'Urso, Consultant Neurosurgeon Email Dr. Wei...

Medical Imaging from Medical Scanner to 3D Model

Rapid Prototyping Medical

A strong software interface is needed to accept input from every type or brand of scanner, to facilitate the selection of an anatomic structure visible in the medical images and to link this Advanced Manufacturing Technology for Medical Applications Edited by I. Gibson 2006 John Wiley amp Sons, Ltd. information to rapid prototyping machines for actual model production. Surgery simulation on a virtual computer model requires specific functions in the software to simulate surgical actions and to...

Solid ground curing SGC

Besides the classical laser-based SLA process, alternative processes using digital mask generators, e.g. liquid crystal displays or digital mirror devices DMDs , have been used successfully to build structures out of polymers and ceramics. In the RP literature this process is also termed solid ground curing SGC . In contrast to traditional UV laser based SLA machines, DLP systems are significantly cheaper and therefore more versatile with respect to material modifications. At the same time, DLP...

EBM fabrication of custom knee implants

The introduction of electron beam melting technology and the development of the titanium material have resulted in a new fabrication method for custom-designed titanium implants and devices. The EBM machine is capable of building parts directly out of titanium to near net shape that require very little finish machining. After final machining, the parts can be polished to a mirror finish to provide excellent bearing surfaces for implants. As is the case with many other SFF systems, multiple...