Chi-Lun Lin

A Process for Design, Verification, Validation, and Manufacture of Medical Devices Using Immersive VR Environments

This paper presents a framework and detailed vision for using immersive virtual reality (VR) environments to improve the design, verification, validation, and manufacture of medical devices. Major advances in medical device design and manufacture currently require extensive and expensive product cycles that include animal and clinical trials. The current design process limits opportunities to thoroughly understand and refine current designs and to explore new high-risk, high-payoff designs. For the past 4 years, our interdisciplinary research group has been working toward developing strategies to dramatically increase the role of simulation in medical device engineering, including linking simulations with visualization and interactive design. Although this vision aligns nicely with the stated goals of the FDA and the increasingly important role that simulation plays in engineering, manufacturing, and science today, the interdisciplinary expertise needed to realize a simulation-based visual design environment for real-world medical device design problems makes implementing (and even generating a system-level design for) such a system extremely challenging. In this paper, we present our vision for a new process of simulation-based medical device engineering and the impact it can have within the field. We also present our experiences developing the initial components of a framework to realize this vision and applying them to improve the design of replacement mechanical heart valves. Relative to commercial software packages and other systems used in engineering research, the vision and framework described are unique in the combined emphasis on 3D user interfaces, ensemble visualization, and incorporating state-of the-art custom computational fluid dynamics codes. We believe that this holistic conception of simulation-based engineering, including abilities to not just simulate with unprecedented accuracy but also to visualize and interact with simulation results, is critical to making simulation-based engineering practical as a tool for major innovation in medical devices. Beyond the medical device arena, the framework and strategies described may well generalize to simulation-based engineering processes in other domains that also involve simulating, visualizing, and interacting with data that describe spatially complex time-varying phenomena.

Optimizing Design with Extensive Simulation Data: A Case Study of Designing a Vacuum-Assisted Biopsy Tool

Design by Dragging (DBD) [1] is a virtual design tool, which displays three-dimensional (3D) visualizations of many simulation results obtained by sampling a large design space and ties this visual display together with a new user interface. The design space is explored through mouse-based interactions performed directly on top of the 3D data visualizations. Our previous study [1] introduced the realization of DBD with a simplistic example of biopsy needle design under a static bending force. This paper considers a realistic problem of designing a vacuum-assisted biopsy (VAB) needle that brings in more technical challenges to include dynamic tissue reaction forces, nonlinear tissue deformation, and progressive tissue damage in an integrated visualization with design suggestions. The emphasis is placed on the inverse design strategy in DBD, which involves clicking directly on a stress (or other output field parameter) contour and dragging it to a new (usually preferable) position on the contour. Subsequently, the software computes the best fit for the design variables for generating a new output stress field based on the user input. Three cases demonstrated how the inverse design can assist users in intuitively and interactively approaching desired design solutions. This paper illustrates how virtual prototyping may be used to replace (or reduce reliance on) purely experimental trial-and-error methods for achieving optimal designs.