I am having a problem with attenuation correction. I have been studying a monitoring method for the spent fuel assembly using the SPECT system. The image was reconstructed using the filtered back projection method. However, the image reconstructed with the FBP method showed low-intensity on the center of the image. So I downloaded CASToR software to improve the image of spent fuel assembly. At first, I used the joseph projector using -proj to test CASToR software. The joseph projector does not permit attenuation correction. And now, I have been using incrementalSiddon projector for attenuation correction. I made a mumap using matlab and the ground truth image. The mumap worked, but the reconstructed image was different from what I had expected. It seems that the mumap was expanded.
Does anyone know how to apply mumap for attenuation correction, or what I do wrong? I used list-mode SPECT data with GATE for 4500 second. And the detector used in my study is a 64 channel multi array.
Thanks in advance.