Automatic outlining of regions on CT scans.

A computer software system for automatic outlining of borders between regions of differing CT numbers on computed tomography scans has been developed. The technique was originally intended for application in defining inhomogeneities for radiation therapy treatment planning; however, several other applications are possible. The system scans an image using a simple threshold model to locate initial outline points and then completes the outline with a border-following algorithm. Results of the automatic outlining system are given along with histograms of the enclosed regions, demonstrating several further applications of these techniques.