A new technique for producing anthropomorphic radiologic phantoms is described. Information from a patient radiograph is used to design the phantom. Optical densities from a digitized radiograph are converted to thicknesses of a phantom material, with corrections for geometry, x-ray spectrum, and scatter. Numerically controlled machining techniques are used to transcribe the anatomic details into the phantom material. High spatial frequencies are reproduced separately from low spatial frequencies using photochemical techniques in order to replicate finer details in the phantom. The result is a phantom consisting of a number of overlays. Radiographs of a breast phantom produced using the technique are shown, energy equivalence to attenuation of breast tissue is assessed, and methods of incorporating fine detail and quantitative features in the phantom are suggested.