[Gate-users] Distinguish original photon energy?

[Larry Pierce]

Dear GATE users, 

I have a question regarding simulation of I-123, with 83% of the emission photons at 159 keV used for imaging. It also has 3% of the photons emitted being higher-energy up to 784 keV and these can contaminate the data and reconstructed image. 

When simulating our SPECT detector, I would like to know the energy of the original photon to determine if it was an “imaging photon” or a “higher-energy photon” that led to the hit or single in the detector. 

Does anyone know of a way to do this in GATE?

I have considered that we may use multiple overlapping spectrum sources with a mixture of imaging and high-energy photons and that the output source ID can then tell us if the originating photon was an imaging photon or a high-energy photon. 

Still, I would like to ask the group for their input if there are other better ways to approach the issue. 

Thank you for your consideration, 

-Larry Pierce