Local cone-beam SPECT reconstruction algorithm for non-uniformly attenuated radon transform

SPECT is one of the nuclear medicine imaging techniques. It can reconstruct the functional image of the organ of interest, and has great help for early diagnosis of diseases. Cone-beam SPECT reconstruction can improve the photon density and spatial resolution of the reconstructed image, but it is time consuming. In clinic, doctors usually just care about the region of interest (ROI), such as heart, not the whole body. Local reconstruction can reduce the reconstruction time. In this paper, we build a framework for local cone-beam SPECT reconstruction with non-uniform attenuation. Firstly, we rebin the cone-beam projection to a fan-beam projection using SSRB method, and then perform a data extrapolation in each slice. Finally, after rebinning from fan-beam projection to parallel-beam projection, the reconstructed images of ROI could be obtained by using Novikov's analytical SPECT reconstruction algorithm. In computer simulation, clear local reconstruction images are obtained, which are almost the same as the ROI images of phantom. Computer simulation results show that our reconstruction framework is feasible.