Hi, I'm not sure we actually ever checked this but it's a good check. Are you using attenuation correction? If not, I expect that the total number of counts in one projection should be equal to the integral of the SPECT image as this is the Radon transform model. So you may want to average the number of counts and not sum it (i.e., divide 8E+6 by your number of projections). Can you check this? Simon
On Tue, Jun 27, 2023 at 8:48 AM Nathan Sinsoilliez <n.sinsoill...@gmail.com> wrote: > Hello everyone, > > I'm currently using rtk to reconstruct SPECT images using OSEM and I have > an issue after the reconstruction. The total count of the image is > completely changed (like 8E+6 in the projections VS 2E+4 when > reconstructed). Also most of the pixels now have decimal values. > Graphically everything seems to be alright though. > > Do you have an idea about what could cause this problem ? > > Best Regards > Sinsoilliez Nathan > _______________________________________________ > Rtk-users mailing list > rtk-us...@openrtk.org > https://www.creatis.insa-lyon.fr/mailman/listinfo/rtk-users >
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