Evaluation of Digital Tomographic Filters

Recently, a technique has been proposed to filter conventional radiographs in order to obtain depth-dependent information by simulating standard tomography. This technique has been referred to as tomographic filtering or tomographic filtration process (TFP). It takes advantage of the finite size of the X-ray source, so that after processing the image of a particular layer is improved, while the others are degraded. This paper briefly reviews this technique and then concentrates on its analytical evaluation. A comparative assessment of tomographic filtering is produced taking as benchmarks two well established radiologic procedures: standard tomography and conventional radiology. The comparison is made on the basis of the following evaluation criteria: the exposure angle, the thickness of the cut, the rate of change of the transfer function, the signal-to-noise ratio, and the radiation dose. Practical evaluations are also shown.