Iterative method for elimination of the Kbeta filter in dual-beam differential tissue absorptiometry

The application of a dual photon beam to the measurement of tissue and tissue-like substances has generally required the use of a filter to attain the required monochromaticity of the lower-energy x-ray photons. In many cases this has the undesirable effect of also severely attenuating the desired low-energy beam. A method for circumventing the use of the filter is described. The technique relies on a knowledge of the initial intensities of the components of the x-ray portion of the dual beam and involves an iterative mathematical procedure. Experimental verification of the method using both tissue and nontissue substances has been carried out. R values obtained with the iterative system show good correlation with filtered values.