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

[Kris Thielemans]

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