Petsurfer - uptake units

Hi, just a question about the measurement units of the uptake values showed by Petsurfer (FS version 6) after a ROI analysis with the no-rescale option activated. Is it some sort of Bq/ml ?
By default, PVC uptake of ROI are values scaled by the intensity in pons. Without scaling, I should get absolute values, but I ignore their units.
Thanks for help !

My command is: /mri_gtmpvc --i pet.nii.gz --reg template.reg.lta --seg gtmseg.mgz --default-seg-merge --auto-mask 1.01 --no-tfe --no-rescale --o gtmpvc.output