It depends on why it failed, which is usually for one of two reasons. The first is that the initialization failed. You can check this by saving the initial registration by passing "--init-reg-out init.reg.dat", then viewing this reg with tkregister2. If this is more than 5 mm or 5 deg off, then you can try a different init method, either spm, fsl, or tune it by hand. The other reason is that your image does not have sufficient gray/white contrast. Some PET scans just don't have good contrast, or the data are very smooth. In this case, bbregister is the wrong tool (use fsl or spm or tune by hand instead).
doug
corinna bauer wrote:
Hello, I am running bbregister with pet scans and a number of the subject's registrations were poor. What is the best way to fix inaccurate coregistrations from bbregister?
Regards, Corinna
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