1. A method of volumetric image reconstruction from partial cone beam data comprising: (a) collecting the partial cone beam data in two-dimensional arrays at a plurality of sampling positions, said collected data corresponding to rays of radiation diverging in two dimensions from a common vertex as the vertex travels along a continuous path; (b) defining a plurality of oblique surfaces throughout a region of interest; (c) identifying rays of radiation which pass through the plurality of oblique surfaces; (d) reconstructing data from the identified rays into a reconstruction cylinder having an axis along a z-direction; and (e) generating a volume data set from the reconstructed oblique surface data.