Simple backprojection

For each image pixel (x,y) at each projection angle o, r is calculated by Eq. (4.1). The measured counts in the projection sinogram corresponding to the calculated r are added to the (x,y) pixel in the reconstruction matrix. This is repeated for all projection angles. Thus, the backprojected image pixel 

Basics of PET Imaging Physics, Chemistry, and Regulations, 

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The simple backprojection has the problem of star pattern artifacts (Fig. 4.1a) caused by shining through radiations from adjacent areas of... 

Finally, the inverse Fourier transformation is performed to obtain filtered projection data in the spatial domain, which are then backprojected in the same manner as in the simple backprojection. With the use of faster computers, the Fourier technique of filtered backprojection has gained wide acceptance in reconstruction of images in nuclear medicine. 

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