Dear Jing Li,


Your question is more about your “raw” data than SPM I guess.

There are at least as many types of PET data as there are PET tracers - which one are you using? If you get six files, you may be using [15O]H2O PET for activation studies - but then the images should not be (exactly) the same. You may be using [18F]FDG PET, and your six files may be PET data with/without attenuation correction, associated CT data, etc - but again they should not be the same. If you use ligand/receptor PET, it would be unlikely that you would get only six frames, and again they should not be the same.

I think you need to get back to the people with whom you acquired the data and find out first what you’re actually looking at.

Once you know this, it should be possible for you to interpret the data easily, as SPM normally applies any scale factors correctly (you can see them in the bottom of the right window when using the DISPLAY function).

Hope this helps!

All the best,

Alexander

-----------------------------------------
Alexander Hammers, MD PhD

Chair in Functional Neuroimaging
Neurodis Foundation
http://www.fondation-neurodis.org/
Postal Address:
CERMEP – Imagerie du Vivant
Hôpital Neurologique Pierre Wertheimer
59 Boulevard Pinel, 69003 Lyon, France

Professor (Honorary Consultant) of Imaging and Neuroscience
Head of PET Imaging Centre
Division of Imaging Sciences and Biomedical Engineering
King's College London
St Thomas' Hospital, London

Telephone +33-(0)4-72 68 86 34
Fax +33-(0)4-72 68 86 10
Email [log in to unmask]; [log in to unmask]





On 25 Jul 2014, at 18:47, Jing Li <[log in to unmask]> wrote:

Hi, all~~

I wanted to know some features in PET data, so I wanted to find out what exactly is the value of data in each voxel... where can I find them? (I didn't found them in the SPM.mat file=(

Also, after pre-processing original data, I got some *.img files, and could display them in SPM. There are 6 *.img files for one subject's one-time scan, like this:

***-000001.img
***-000091.img
***-000181.img
***-000271.img
***-000361.img
***-000451.img

Each of them displays the same. Why one scan is divided into 6 file? (Should I combine them to get data) I'm confused.

Any suggestion helps! I'm looking forward to your kind reply!  

Best Regards,
Jing Li

 
Department of Control Science and Engineering, 
Chu Kochen Honors College
Zhejiang University
Tel (+86)1885-828-0435 / (+1) 617-335-0412