1. In a digitized tomosynthesis method for projecting a 3D volumetric image of an object onto a virtual projection plane, the image being defined by object voxels, in which a ray of energy from a source travels through the object to impinge on an energy sensing image plate having an active area defining an image plane and in which an image is acquired by the energy sensor at successive relative rotational positions of the object and source, wherein a Z axis is defined as the axis of relative rotation of the object, an X axis is defined as relatively horizontal at right angles to the Z axis, a Y axis is defined as relatively vertical at right angles to the X and Z axes, rotation about the X axis is defined as pitch, rotation about the Y axis is defined as yaw, and rotation about the Z axis is defined as roll, and wherein the image plate is parallel with the XZ plane and the source is positioned above the XZ plane with its optical axis defining the center of a radiation cone and intersecting the image plate at approximately its central pixel, the improvement according to which a 3D volumetric image of the object is projected by steps comprising: computing the coordinate of an object voxel referenced to the image plane; computing the image plane intercept of the ray of energy from the source through the object voxel; and projecting a reconstructed 3D volumetric image of the object onto the virtual projection plane.