I had a problem when reconstructing some PET dicom images (attached) using to3d. It gave a warning as below:

++ to3d WARNING: 142056 negative voxels (24.7726%) were read in images of shorts.
++ It is possible the input images need byte-swapping.

More importantly, the resulting 3D image has strong negative voxels inside the brain surrounded by strong positive voxels. It looks like those values are overflowed and wrapped to the negative side. I tried to use -2swap option, but it was ignored by to3d. The scripts are like below:

setenv AFNI_DICOM_RESCALE YES
set fileList=""
for each i (`ls | sed s/Image.//g | sort -g`)
set fileList="$fileList Image.$i"
end
to3d -2swap -prefix petscan $fileList

Any suggested solutions on this? Thanks!