[gate-users] Discovery ST images

[Kris Thielemans]

> 
> For the ring diamter, STIR says it is 90.3cm for DST but I 
> have 88.6 cm and I used STIR for reconstrction, how big an 
> error does this give me ?
> 

Here is the reason for the difference:

- face to face crystal distance			 	= 886.2 mm
- face to face crystal distance plus  penetration depth of the
photons into the   crystal	= 903.0 mm

STIR at present uses the 2nd one.

> Also the bin size read off from GATE ( 1/2 
> crystal-center-to-crystal-center ) is 3.27 mm while STIR uses 
> 3.1695 mm.
> 

This is the GE arc-corrected bin-size. The GATE data are not arc-corrected,
so binsize does not make sense there.

> The next part is for arc correction of the data.  How is this 
> done , in STIR that is ? I just modified to header file to 
> say the data was arc corrected but I know that GATE han't done that.
> 

You can't yet yet, unless you write some code. See STIR-users mailing list
archive.



I think you should now start to ask GATE questions on the GATE list, and
STIR questions on the STIR list.

Kris