Thanks for your kind and useful reply.
I wanted to make sure my interpretation was right:
Step 1: was done by SPM function: Coreg:estimate and the registration information would be stored in the header of source images (no other output would be found)
Step 2 and Step 3:just as routine DARTEL process on T1 images
Step4: as in DARTEL toolbox: normalise to MNI space option and use source images (PET) from Step1.
For receptor/transporter binding potential images, I suspected we should choose Preserve Amount in Step 4 according to previous discussion:
Furthermore, considering the image features of PET or even SPECT images, it might have to smooth such images with large amount (ex 12 mm compared to default 8 mm in DARTEL). I wonder if such was suitable if we wanted to perform further analysis by BPM that used both VBM and PET/SPECT images concurrently as in this subject:
Thanks for your help~