A semiautomatic tool for 3D medical image analysis using active contour models

We describe a computerized tool designed to improve the efficiency with which clinicians can delineate volumes of interest in multi slice medical data such as NMR and CT images. The tool allows a trained user to create deformable models that can be used to search for edges or regions. Models can also be copied from previously analysed images into fresh slices, and frozen so they can only translate, rotate and scale, without deforming. In this way an accurate model can be used to extract an object from several adjacent slices. Surfaces are then reconstructed from the models using conic splines. By applying these techniques to objects such as tumours, it should be possible to generate three-dimensional images that are accurate enough to use when planning surgery and radiotherapy.