How to spatially normlize PET images without involving T1-weighted MRI?

[h1310321230]

Documents describe below:
"Steps:
1.Spatially normalize FDG-PET to MNI using SPM12 Normalize.
There is a group template option for PET: first a group template is created, then all subjects are normalized to this group template."

I have some questions:

1. All FDG-PET images use spm12 normlise module to warp PET images to the MNI space. Is the group template created by computing the average image of all warped PET images ? What is the tissue probability map used in this process? Is the /tpm/TPM.nii?
2. Are all subjects normalized to the template image created by 1 using SPM8?
3. How to normalize PET images of novel tracers without involving T1-weighted MRI?

[alexsavio]

Hi!

1. Yes. Yes :)
2. I don't understand it, could you please rephrase?
3. Without a matching T1 MRI, it's a hard task, you would need a common template for that tracer?

[h1310321230]

2. As described in the first question, we first get a group template by spm12. Then, are you applying this group template to all subjects by using spm8? or spm12 normalise module or other tools? As far as I known, the template image of SPM12 is 4D image.
3. without T1 MRI, can I use spm12 to generate a group template for a new born tracer and do the following steps? If I would like to use spm12 default TPM.nii MRI tissue probability map to normalize PET images of new tracer to generate a group template as FDG-PET, is this feasible?