Development and application of the new dynamic NURBS-based cardiac-torso (NCAT) phantom
W. Paul Segars, B.M.W. Tsui, D.S. Lalush, E.C. Frey, D. Manocha, and M.A. King
Simulation is a powerful tool for characterizing, evaluating, and optimizing medical imaging systems. An important aspect of simulation is to have a realistic phantom or model of the human anatomy. We develop a realistic and flexible computerized dynamic torso phantom and investigate its usefulness in medical imaging research.
METHODS AND MATERIALS:
organ shapes are modeled with non-uniform rational b-splines
or NURBS surfaces using a unique, detailed human image dataset as the basis for
the formation of the surfaces. With its basis upon human data and the inherent
flexibility of the NURBS primitives, the phantom can model organ shape more
realistically than phantoms based on simple geometric primitives while
maintaining the flexibility to model anatomical variations and patient motion.
An important innovation of the research is the extension of NURBS to four (4D)
dimensions to model the cardiac and respiratory motions. The NURBS cardiac
model was developed based upon a tagged magnetic resonance imaging (MRI)
dataset of a normal patient and three-dimensional (3D) angiogram data. NURBS
models for the remaining torso organs were developed based on the
Fig. 1. (Left) Anterior view of the 4D NCAT phantom. (Middle) Cardiac and respiratory motion models of the NCAT phantom. (Right) Emission and transmission simulations performed using the phantom.
The 4D NCAT phantom was found to provide a realistic and flexible model of the human anatomy and cardiac and respiratory motions, Fig. 1. Combined with accurate models of the imaging process, it can be used to produce simulated imaging data that closely mimics that of actual patients. The simulation results of the pilot simulation studies using the NCAT phantom were found to be consistent with that found in patient studies.
With its realistic model of the human anatomy and physiology, the 4D NCAT phantom provides a unique and useful tool in medical imaging research especially when the effects of cardiac and respiratory motions are important.
NIH research grant R01EB000168