Hi Bate,
Preprocessing in SPECT needs and extra step with respect to fMRI: the intensity normalisation. The number of counts per pixels depends on a high number of uncontrolled variables, such, real radioactivity at the time of the radiotracer delivery, time between delivery and image acquisition, detector efficiency, subjects weight,…. which makes images pixel activity not to be directly comparable from one subject to other. In case you guess the weight of higher/lower uptake areas could have a minimal impact on mean uptake of the whole brain, the easiest solution would be to activate the proportional scaling in the analysis. Otherwise you should normalise the intensity of the images by levelling the uptake of any area known/supposed not to be affected by the effect you are testing. That could be done by means of imcalc, by multiplying each image by the factor: common new value/mean uptake of the reference region. Just in case you did not take that into account
Hope this helps
Carles Falcon
> El 8 ag 2023, a les 9:23, Batel Yifrah <[log in to unmask]> va escriure:
>
> Hello everyone,
>
> I have previously utilized SPM12 for fMRI analyses and I am now endeavoring to employ it for SPECT analyses. Unfortunately, I am encountering difficulties in finding comprehensive information on the process of conducting SPECT analysis using SPM. Could someone kindly direct me to resources or references that provide guidance on SPECT analyses within the SPM framework?
>
> Additionally, I am facing challenges in converting my SPECT images from DICOM format to NIfTI using SPM. Despite my efforts, I have not been successful in this transformation. I would greatly appreciate any assistance or advice in resolving this issue.
>
> Thank you sincerely for your help.
>
> Best regards,
> Bate
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