A computer-implemented method includes obtaining, at a processor, a tomographic image of a phantom, wherein the phantom includes heterogeneous regions having a plurality of materials with varying attenuation coefficients. The method also includes automatically segmenting, via the processor, the heterogeneous regions from the tomographic image to generate a segmented image. The method further includes automatically identifying, via the processor, a plurality of regions of interest having varying attenuation coefficients within the tomographic image based on the segmented image. The method still further includes automatically labeling, via the processor, each region of interest of the plurality of regions of interest as representing a particular material of the plurality of materials. The method even further includes outputting, via the processor, a labeled image of the tomographic image. The method may be utilized in quality assurance testing and calibration.