Fred Dech

Virtual reality: new method of teaching anorectal and pelvic floor anatomy.

AbstractPURPOSE: A clear understanding of the intricate spatial relationships among the structures of the pelvic floor, rectum, and anal canal is essential for the treatment of numerous pathologic conditions. Virtual-reality technology allows improved visualization of three-dimensional structures over conventional media because it supports stereoscopic-vision, viewer-centered perspective, large angles of view, and interactivity. We describe a novel virtual reality-based model designed to teach anorectal and pelvic floor anatomy, pathology, and surgery. METHODS: A static physical model depicting the pelvic floor and anorectum was created and digitized at 1-mm intervals in a CT scanner. Multiple software programs were used along with endoscopic images to generate a realistic interactive computer model, which was designed to be viewed on a networked, interactive, virtual-reality display (CAVE® or ImmersaDesk®). A standard examination of ten basic anorectal and pelvic floor anatomy questions was administered to third-year (n = 6) and fourth-year (n = 7) surgical residents. A workshop using the Virtual Pelvic Floor Model was then given, and the standard examination was readministered so that it was possible to evaluate the effectiveness of the Digital Pelvic Floor Model as an educational instrument. RESULTS: Training on the Virtual Pelvic Floor Model produced substantial improvements in the overall average test scores for the two groups, with an overall increase of 41 percent (P = 0.001) and 21 percent (P = 0.0007) for third-year and fourth-year residents, respectively. Resident evaluations after the workshop also confirmed the effectiveness of understanding pelvic anatomy using the Virtual Pelvic Floor Model. CONCLUSION: This model provides an innovative interactive educational framework that allows educators to overcome some of the barriers to teaching surgical and endoscopic principles based on understanding highly complex three-dimensional anatomy. Using this collaborative, shared virtual-reality environment, teachers and students can interact from locations world-wide to manipulate the components of this model to achieve the educational goals of this project along with the potential for virtual surgery.

Assembly Planning Effectiveness Using Virtual Reality

Planning the sequence of components (or parts) to be assembled during manufacturing is an important application problem for virtual environments for three main reasons. First, it is a difficult combinatorial optimization but a highly visual problem. Second, a majority of assembly operations in factories (with the exception of simple pick-and-place operations) are still performed manually, because they are difficult to automate. Hence, it is an important problem involving human-machine interface. Third, there are a number of assembly operations which require dextrous operator training. Hence, it is also an important training problem. Recent research suggests a promising approach for assembly determination based on using heuristic rules to generate soft constraints in addition to the regular hard quantitative constraints due to part geometry and topology. We believe that the emergence of virtual environments can enable us to systematically use these soft constraints, which previously has not been possible. In this paper, we report results of experiments involving fifteen voluntary participants using a nonvirtual reality (VR) environment involving blueprints, a nonimmersive desktop VR environment, and an immersive projection-based VR environment to first teach participants skills in handling soft and hard constraints for assembly planning through examples, and then to measure the effectiveness of their learnt skills in solving a different example problem. We have classified soft constraints as infeasibility constraints, reorientation constraints, difficulty constraints, instability constraints, and dissimilarity constraints. A significant observation is that the participants could, on average, perform the assembly operations in approximately half the time in the immersive and nonimmersive VR environments than in the traditional environment using blueprints.

Tele-Immersion: Preferred Infrastructure for Anatomy Instruction.

UNDERSTANDING SPATIAL RELATIONSHIPS among anatomic structures is an essential skill for physicians. Traditional medical education—using books, lectures, physical models, and cadavers—may be insufficient for teaching complex anatomical relationships. This study was designed to measure whether teaching complex anatomy to medical students using immersive virtual reality is an improvement over traditional methods. Using a networked immersive virtual reality system, anatomy-teaching assistants gave 20-minute workshops to first-year medical students one day before or after a traditional three-hour lecture/laboratory session. Students who attended only the traditional session served as a comparison group. Improvements from pretest to posttests demonstrated a statistically significant advantage to the brief virtual reality session over the traditional session. Improvement for those who were exposed to both the traditional and immersive sessions was also statistically better than for those exposed only to the traditional session. The application tested proved to be an effective enhancement to traditional surgical-anatomic educational curricula.

Precisely exploring medical models and volumes in collaborative virtual reality

We describe a virtual-reality widget library and two medical applications built on the widget library. These two applications, education using surface models and radiological volume visualization, make use of collaborative interaction techniques. These techniques support a high degree of precision with respect to manipulation of data and data parameters. The 3D widgets instantiated in these applications are synchronized between clients in order to facilitate the high degree of interactivity necessary for productive investigation of shared medical models and volume data. We discuss challenges that face the investigator in an immersive 3D environment as opposed to that of a 2D desktop environment. We describe how these differences have led us to criteria for development of the shared 3D Virtual Reality (VR) graphical user interfaces (GUIs) used in the biomedical applications presented. We review our educational validations already conducted for the surface model exploration application and preview our future work toward a single advanced biomedical collaboration environment.