Development of an interactive software application to model patient populations in the 4D NURBS-based cardiac torso phantom

The 4D NURBS-based Cardiac Torso (NCAT) phantom was developed to provide a realistic and flexible computerized torso phantom to be used in medical imaging research. The organ shapes in the NURBS-based phantom are modeled with non-uniform rational b-splines or NURBS surfaces using the Visible Human CT data set as the basis for the formation of the surfaces. Since it is based on human data, the phantom has the ability to model organ shape and anatomical variations more realistically than phantoms based on simple geometric primitives. To this point, the NCAT phantom has been limited to simulating variations upon the anatomy of the Visible Male. The authors extend the abilities of the phantom to include simulation of female patients. Two breast models, simulating the prone and supine positions, were developed using 3D NURBS surfaces. As is the case with the other organs of the torso, the NURBS definition of the breasts allows a high degree of flexibility to model anatomical variations. The authors develop an interactive software application that will allow a user to modify the NURBS surfaces that define the different organs of the NCAT phantom in order to generate male and female patients with varying anatomy. The software application provides 3D and 2D views of the phantom and includes several transformations that can be used to alter the anatomy. It also includes the ability to import patient data from which the user can manipulate the organs of the phantom to match the specific patient anatomy. It is concluded that this software application is a useful resource in creating patients with varying anatomy to be used in medical imaging research studies that involve a population of patients.