[gate-users] RE: [gate-devel] GE Advance

[Kris Thielemans]

Hi

> 
> 2) another solution, which is more practical, is to use the 
> STIR software. 
> However, I don't believe STIR knows about the DLS geometry at 
> this point. Is that right Kris? 

It'll be in 1.3 very soon. Trivial change anyway.

> In any way, to reconstruct 
> the Gate data using STIR, let's say for a GE Advance  model, 
> you also need to bin your Coincidences according to the STIR 
> data format for the Advance. To do that, you need to re-write 
> the Michelogram.ima file according to STIR format, which 
> different than that for the Advance. In GE Advance, the 
> segments are arranged as 0, +1, -1, +2, -2, ... However in 
> STIR, please kris correct me if I'm wrong, the segments are 
> arranged as: -11, -10, .....+10, 11. Once you do that, 
> reconstruction with STIR becomes very straight forward. 
> 
If you use the interfile format, the segment order is arbitrary.
However, you have to  specify it using the 
"minimum ring difference per segment" (and "maximum...") pair.

If you use ECAT7, the format is obviously fixed to whatever ECAT7 uses,
which is 0, -1, +1, -2, +2 (in STIR conventions).

If you use VOLPET, currently STIR can only read Advance (=Discovery LS)
data. I'm waiting for permission from GE to release software that can
read Discovery ST data.

A final note: "GE segments" are not the same as "CTI segments". An
oblique GE segment has essentially span=2 (an even number!), while the
direct segment has span=3. At present, STIR splits 1 oblique "GE
Segment" into 2 "CTI segments" (each with span=1).

Kris