Creating a human phantom for the virtual human program

A high-resolution human phantom--a computer representation of the human anatomy--is needed as part of the Virtual Human (VH) simulation environment being developed by Oak Ridge National Laboratory and collaborators. Within the VH environment, this 3D anatomical phantom is coupled with physiological models and data to investigate a wide range of human biological and physical responses to stimuli. This paper describes how the phantom was created using the Visible Human (male) image data from the U.S. National Library of Medicine. Initially, X-ray computed tomography (CT) as well as photographic images of the Visible Human (male) torso were segmented and classified with software developed using IDL. From these data, non-uniform, rational B-spline (NURBS) spatial models were fitted to represent the surfaces of discrete body structures such as bones and organs. This collection of NURBS models, referred to as the NURBS VH, defines the fundamental Virtual Human phantom. The NURBS VH is compatible with modeling and animation software, enabling dynamic manipulation of body structures and their associated visual representations. The organization of the structural data lends itself to existing and evolving Web and electronic communication standards, making it attractive for applications such as medical training. In addition, finite-element (FE) meshes were created from the NURBS VH for use in trauma simulation, electromagnetic field exposure modeling, dosimetry, and other applications requiring spatially-defined tissue properties. The ability to scale the NURBS VH to account for age and size and the ability to easily animate NURBS objects yield a very flexible human phantom for the VH simulation environment.