PET

PET_Brain_AC.nii.gz

This is the attenuation-corrected PET image from which mSUVr is derived. This is "The PET Scan".

What attenuation correction means: PET photons get absorbed or scattered by tissue and skull before reaching the detector. Without correction, deeper brain regions look artificially dim. The scanner uses a CT-derived attenuation map to fix that.

PET_Brain_(calculated_AC).nii.gz

This is another attenuation-corrected reconstruction, but produced through a different reconstruction pipeline or algorithm. PET_Brain_AC is the primary PET AC image.

MU_MAP_PET_Brain.nii.gz

μ-map = attenuation coefficient map

It’s derived from the CT scan and used during PET attenuation construction (the above image types).

Brain_AC_CT_Brain_(CTAC).nii.gz

CT scan used to generate the μ-map.

Brain_CT_Brain_Bone_Recon.nii.gz

Optimized for bone detail. Very likely irrelevant for our needs.

Brain_CT_Brain_Standard_Recon.nii.gz

General diagnostic CT?

Brain_Topogram_0.6_T20f.nii.gz

PET/CT equivalent of a localizer. Not needed for analysis.

PET_Statistics.nii.gz

Why is this even a .nii?

Brain_Patient_Protocol.nii.gz

Seriously, why would this be a nii?