Practical use of VR in Medicine

Introduction

The practice of medicine and major segments of the biologic sciences have always relied upon visualizations of the relationship of anatomic structure to biologic function. Traditionally, these visualizations have either been direct, via vivisection and postmortem examination, or have required extensive mental reconstruction as in the microscopic examination of serial histologic sections. The revolutionary capabilities of new 3D and 4D imaging modalities as well as new 3D scanning microscope technologies underscore the vital importance of spatial visualization to these sciences. Computer reconstruction and rendering of multidimensional medical and histologic image data obviate the taxing need for mental reconstruction and provide a powerful new visualization tool for biologists and physicians. Voxel-based computer visualization can serve a number of important uses in basic research, clinical diagnosis and treatment or surgery planning, but it is limited by relatively long rendering times and minimal possibilities for image object manipulation.

Use of Virtual Reality

The use of virtual reality technology opens new realms in the teaching and practice of medicine and biology by allowing the visualizations to be manipulated with intuitive immediacy similar to that of real objects, by allowing the viewer to "enter" the visualizations to take up any viewpoint, by allowing the objects to be dynamic - either in response to viewer actions or to illustrate normal or abnormal motion and by engaging other senses such as touch and hearing (or even smell) to enrich the visualization. Biological applications extend across a range of scale from investigating the structure of individual cells through the organization of cells in a tissue to the representation of organs and organ systems, including functional attributes such as electrophysiologic signal distribution on the surface of an organ, and are of use as instructional aids as well as basic science research tools. Medical applications include basic anatomy instruction, surgical simulation for instruction, visualization for diagnosis and surgical simulation for treatment planning and rehearsal.

Although the greatest potential for revolutionary innovation in the teaching and practice of medicine and biology lies in dynamic, fully immersive, multisensory fusion of real and virtual information data streams, this technology is still under development, and not yet generally available to the medical researcher. There are, however, a great many practical applications requiring varying levels of interactivity and immersion that can be delivered now, and that will have an immediate impact on medicine and biology. In developing these applications, both hardware and software infrastructure must be adaptable to many different applications operating at different levels of complexity. Interfaces to shared resources must be designed flexibly from the outset, and creatively reused to extend the life of each technology to realize satisfactory return on the investment.

Crucial to all these applications is the facile transformation between an image space organized as a rectilinear N-dimensional grid of multivalued voxels and a model space organized as surfaces approximated by polygonal tiles. The required degree of integration between these realms varies significantly between purely educational or instructional applications

- which may be best served by a small library of static ...