Accelerated image reconstruction for a cylindrical positron tomograph using Fourier domain methods

The authors present a method to reconstruct projection images through assembly in the Fourier domain, rather than by backprojection. By bypassing the rate-limiting backprojection step of filtered backprojection, the proposed algorithm operates more quickly than previous methods. Fourier domain operations are also used to form forward-projected views of the imaged object; portions of these views are required to operate a full three-dimensional reconstruction using the cross-plane projection planes. Inaccuracies in images recovery and artifacts in the image are reduced by oversampling in the Fourier domain; this is easily accomplished by zero-padding the projection data prior to entering the Fourier domain. These Fourier domain algorithms form the basis for the reconstruction algorithm in PCR-II, a volumetric positron imager under construction at Massachusetts General Hospital.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>