ABSTRACT
T rue three-dimensional (3D) imaging is becoming more accessible with the continued devel-opment of instrumentation. Just as the pixel is the unit of brightness measurement for a two-dimensional (2D) image, the voxel (volume element, the 3D analog of the pixel or picture element) is the unit for 3D imaging; and just as processing and analysis is much simpler if the pixels are square, so the use of cubic voxels is preferred for three dimensions, although it is not as often achieved.
