Spatially accurate 3D visualization of medical images during image-guided surgery

During Interactive Image-Guided Surgery (IIGS), a surgeon uses data from medical images to help guide the surgical procedure. At Vanderbilt University, an IIGS software system called Orion has been developed which is capable of displaying up to four 512 x 512 images and the current surgical position using an active optical tracking system. Currently, Orion is capable of displaying data from any tomographic image volume (MR, CT, PET) and from any NTSC video image. We intend to display three-dimensional information as well as the tomographic images. This would provide the surgeon with valuable anatomical information that is not readily obtained from the tomographic slices alone. We have implemented an additional display module for this purpose. Before the surgery a set of rendered images is created, each with a different angular view of the tomographic volume in order to surround the site of surgical interest. The major objectives of the module are to display the appropriate rendered image from the set, identify the current probe position on the selected image, and provide an indication of distance between the probe and the physical point of the anatomy indicated on the image. This can provide the surgeon with vital information such as distance to blood vessels, tumors, or other critical structures.