[Gate-users] Fwd: Define two-ring SPECT

[Débora Salvado]

Hi

I was trying to define a SPECT system with two rings of detectors, aligned
to Y, and one next to the other.
To build the two rings I used the following lines, after defining the
geometry of the SPECThead:
/gate/SPECThead/repeaters/insert ring
/gate/SPECThead/ring/setRepeatNumber 27
/gate/SPECThead/ring/setPoint1  0. 1. 0. mm
/gate/SPECThead/ring/setPoint2  0. 0. 0. mm
/gate/SPECThead/repeaters/insert cubicArray
/gate/SPECThead/cubicArray/setRepeatNumberY 2
/gate/SPECThead/cubicArray/setRepeatVector 0. 52. 0. mm

These are my questions:

1. When I run my code, I get several messages like this one:
"[GateToProjectionSet::Fill]:
Received a hit with a wrong head ID (40): ignored!"
Always with numbers for head IDs between 27 and 53, which I believe they
refer to one of the rings. Is that it? How can I correct this?

2. How does it work for the digitizer and the projections when we have two
rings? How does GATE know which projection belongs to which detector?

3. I would like to rotate one of the detector rings a few degrees in
relation to the other detector ring, how can I do that?

Regards
Debora Salvado
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