Three-dimensional differential absorption x-ray cone-beam microtomography using balanced filters and algebraic reconstruction

A new x-ray tomographic method to image a particular element is proposed and described. This method uses an x-ray tube spectrum and a pair of balanced filters with absorption edges just above and just below the edge of the desired element. The proposed system consists of a microfocus x-ray tube as an x-ray source and a 2-D detector array to collect projection data. The main advantage of this system over traditional differential tomography using two monoenergetic sources is its easy application to fan-beam or cone-beam geometry without reducing too much its intensity. ART is used to reconstruct the 3-D images from the simulated projection data generated by a Monte Carlo program. Computer experiments demonstrate the feasibility of selective imaging in cone-beam geometry. (author)