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

Abstract

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.

Keywords:

• Digital X-ray
• Point extraction
• 3D reconstruction
• Rapid prototyping
• Boolean operation