NURBS-based 3-D anthropomorphic computational phantoms for radiation dosimetry applications.

Computational anthropomorphic phantoms are computer models used in the evaluation of absorbed dose distributions within the human body. Currently, two classes of the computational phantoms have been developed and widely utilised for dosimetry calculation: (1) stylised (equation-based) and (2) voxel (image-based) phantoms describing human anatomy through the use of mathematical surface equations and 3-D voxel matrices, respectively. However, stylised phantoms have limitations in defining realistic organ contours and positioning as compared to voxel phantoms, which are themselves based on medical images of human subjects. In turn, voxel phantoms that have been developed through medical image segmentation have limitations in describing organs that are presented in low contrast within either magnetic resonance or computed tomography image. The present paper reviews the advantages and disadvantages of these existing classes of computational phantoms and introduces a hybrid approach to a computational phantom construction based on non-uniform rational B-spline (NURBS) surface animation technology that takes advantage of the most desirable features of the former two phantom types.