Dear SPMīs,
would anybody have an advice w/r to beta-CIT SPECT? Maybe somebody has
already created a template for this DA/5HTergic tracer?
TIA-
Andreas
----- Original Message -----
From: "John Ashburner" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, November 02, 2001 7:27 PM
Subject: Fwd: Re: Creating a I-123 QNB SPECT Template
> > I am wishing to create a I-123 QNB SPECT template in MNI space from our
> > bank of 23 normal subjects.
> >
> > These images show us the Acetylcholinergic M1 receptor densities in
brain.
> > Visually there are similar to the standard blood flow images except
there
> > is no uptake in both the cerebellum and thalamus.
> >
> > So really the question is, should I normalise these images to the
generic
> > SPECT
> > template in SPM99, and would this be sufficient. Or create our own I-123
> > QNB template as mentioned above?
> >
> > Also if it is feasible to create our own template, what is the best
method
> > to do this? Is it to individually register each I-123 QNB image to the
> > SPECT template
> > in SPM then create a mean image from the registered images, then finally
> > re-register the mean image again to the generic SPECT template in SPM.
> > The resulting mean-registered image would then be our template.
>
>
> I would be inclined to generate a I-123 QNB SPECT template by affine
> normalising a bunch of images to the existing SPECT template, writing them
> with the "template" bounding box, averaging and smoothing by 8mm.
>
> The affine registration will hopefully be reasonably robust to the missing
> cerebellum and thalamus. If not, then what you can do is to weight the
> registration so that these regions have zero weighting in the template
> image. There is a description of how to do this at:
>
http://www.psychology.nottingham.ac.uk/staff/cr1/mritut.html#Normalize
>
> The description is about damaged brains and MRI, but it could equally
apply
> to missing structures in the images.
>
> I would also suggest taking a look at Meyer et al in NeuroImage 9:545-553
> (1999) for a few clues.
>
> Best regards,
> -John
>
>
> --
> Dr John Ashburner.
> Wellcome Department of Cognitive Neurology.
> 12 Queen Square, London WC1N 3BG, UK.
> tel: +44 (0)20 78337491 or +44 (0)20 78373611 x4381
> fax: +44 (0)20 78131420
> http://www.fil.ion.ucl.ac.uk/~john
> mail: [log in to unmask]
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