[gate-users] Re: [Stir-users] interfile headers for ECAT 953 system from Gate output

[Qianmei Zhang]

Thank you again Kris,

I know what you mean. But as long as I define the system of ECAT 953, no 
matter how i change the radius of scanner, the bin is always 3.1 mm from 
gate output.

Another thing is that  I couldn't run ifheaders_for_ecat7 to make 
interfile headers that point to the Ecat7 file without changing the bin 
sizes to make them match to each other.  That is, ifheaders_for_ecat7 
(the version 1.2) may use the Scanner value.

Qianmei



Kris Thielemans wrote:

>Hi
>
>  
>
>>I got the images. Another question is: the  radial bin  size  of the 
>>output of the ECAT 953  system from Gate is 3.1 while in STIR it is 
>>3.129, 
>>    
>>
>
>Nobody agrees on this number. They depend on the ring radius for the
>scanner and the depth of interaction (DOI). CPS tells me they even have
>used different values for the DOI in different versions of the
>reconstruction software.
>
>I don't know how GATE decides on that number, but STIR uses the value
>produced by the scanner (in ECAT6).
>
>  
>
>>In order to make interfile headers for ecat7 file, i 
>>changed the 
>>parameter in STIR/bulidblock/scanner.cxx to make it match. and then 
>>compile the STIR again. But i am not sure whether it is right 
>>or there 
>>is anyother parameters whould be changed as well.
>>
>>    
>>
>
>There's no big need to do that for several reasons:
>- the number disagree with less than 1%
>- the radial bin size is ignored by STIR when using non-arccorrected
>data (it only uses the ring radius)
>- I'm not sure if ifheaders_for_ecat7 uses the Scanner value or the one
>in the ECAT7 file (I think 1.3 uses the one in the file) but both should
>work well enough.
>
>Kris Thielemans
>(kris.thielemans at imperial.ac.uk)
>Hammersmith Imanet
>Du Cane Road
>London W12 0NN
>UK
>http://www.HammersmithImanet.com/~kris
> 
> 
>
>  
>