You can try - but it is a little bit tricky.
The easy approach would be to use the Normalise button, selecting a
T1-w template for the MR (if your MR is T1-weighted), and doing the
same with the CT, but using the PET Transmission scan template. This
may give vaguely acceptable results, but they are not ideal. It
certainly would not be my first choice for doing this sort of thing.
For a bit more accuracy, you could try the New Segment toolbox for
spatially normalising the data. For the CT image, I suggest extremely
heavy regularisation for the bias correction (because CT should not
have MR intensity non-uniformity artifact), and changing the number of
Gaussians used for (eg) the first tissue class to Inf. This will then
use a non-parametric representation of the intensity distributions.
Make sure you specify that you want it to write out deformation
fields. You probably don't want to save any tissue class images,
although thay can be useful for QC.
After running the segmentation, you should end up with a y_*.nii and
an iy_*.nii for the two scans. You can use these to spatially
normalise your data via the Deformations Utility of SPM8. If your
main aim is actually to warp the MR of one subject so that it overlays
the CT of another, then you will need to compose the deformations
together. This can also be done with the Deformations Utility. Note
that this was intended to have the flexibility that more advanced
users may want, so it is not totally straightforward to use. If/when
you get stuck, email the list for further advice.
There is a lot of other software out there, which may also do the job
fairly well. One example that I have heard good things about is
available from:
http://www0.cs.ucl.ac.uk/staff/M.Modat/Marcs_Page/Software.html
It includes information-theoretic nonlinear registration, so should be
able to directly align the CT and MR scans of different subjects.
Best regards,
-John
On 5 September 2012 17:07, parisa Tahafchi <[log in to unmask]> wrote:
> Hello SPM,
> I'm beginner in SPM, I want to do an intersubject, intermodality(MR and CT)
> registeration with SPM, can I use normalization for this purpose?
> I appreciate it if anyone could give a little explanation about this
> question.
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