4. From DICOM to Model4.1. CT ScanningStandard DICOM data from the 17-AAG HSP inhibitor patients CT scan were transferred to CDROM. This was imported into OsiriX.4.2. OsiriX ProcessingOnce in OsiriX, the series was ��double-clicked�� to open it into the standard 2D viewing windows. From the ��3D Viewer�� drop down menu, ��3D Surface Render�� was selected and the standard defined values were accepted (Figure 5).Figure 5Surface rendering. A surface render was produced which converted the images into a 3D data point ��mesh�� that can be exported from OsiriX as an.obj file (Figure 6). An.obj file is a geometry definition format originally developed by Wavefront Technologies. The file format is open and has been adopted by other 3D graphics applications.Figure 6Exporting as an.obj file.4.3. Mesh Processing��MeshLabThis.

obj file was then opened within MeshLab (http://meshlab.sourceforge.net/). MeshLab is an open-source system for the processing and editing of unstructured 3D triangular meshes. This software allows the manipulation of the 3D image to remove unwanted artefact and to isolate specific bones or sections. The mesh must be ��cleaned�� by removing duplicated, unreferenced vertices, null face and using automatic filling of holes if required (Figure 7). This is done from a drop down menu under ��filters.�� Once these operations have been performed, the mesh is saved as an.stl file.Figure 7��Cleaning�� of the mesh.STL is a file format native to the stereolithography computer-aided design (CAD) software created by 3D Systems (Rock Hill, SC).

This format is supported by many software packages and is widely used for rapid prototyping and computer-aided manufacturing. Importantly this file contains only data points and does not contain patient-identifying information. This file can be uploaded to a commercial 3D printer for production.4.4. Cost ComparisonsSeveral commercial companies offer an RP service. Cost comparisons were made from quotations. Seven companies were identified in response to the Google query <3D printing> (accessed 09/07/10). A further company (Materialise http://www.materialise.com/) was added because of reports [3, 7, 42] of its ability to prototype for orthopaedic applications. Companies were approached for a quote to build a 3D rapid prototype of both forearm bones from CT-DICOM data for a patient with a malunion after fracture (it was indicated that standard DICOM data could be supplied).

Seven companies replied��all requiring file conversion to an appropriate format. Quote estimates for printing of converted files were supplied by 3 companies�� ��420 �� 40 (mean �� SEM; n = 3). Quotes for file conversion from DICOM data were given by 2 companies ((i) ��480, (ii) GSK-3 ��85/hr). Therefore an estimate of the expense of acquiring a 3D rapid prototype of both forearm bones from CT-DICOM data, using commercially available avenues, is ��500�C900.4.5.