Gate SPECT Reconstruction Projection Image .sin format.

General Discussions
1

Dear Castor Users,

I am a new user, inquiring about Castors capabilities with GATE MC.

Ideally, I would like to model a dynamic spect (D-SPECT) system and output a projection image (.sin and .hdr) from a volume source and then reconstruct the projection image.

Question 1)

Is Castor capable of reconstructing a. sin and. hdr projection output from a SPECT image from Gate?

  • I see a lot about root output but, I don’t believe this format is useful for SPECT. It would be a .sin (projection) & .hdr (header).

Question 2)

Would a D-SPECT system be too tricky to reconstruct since it is unconventional?

-12 close panels sweeping, should I switch to a more traditional SPECT type?

Thanks all and I appreciate all suggestions,

Kurt Van Delinder

2

Hi Kurt,

The GATE conversion functions in CASToR are restricted to ROOT output indeed. The detected singles are rebinned into pixels accordingly to their GlobalPosX/Y/Z root variables and the pixel matrix (set by the user). Also, the converter assumes parallel collimators are used. However, there are some functions in the code for the conversion of gate projections (.hdr/.sin), but there have not been thoroughly tested. I could send you a version of the code with these functions enabled if you want to give it a try.

CASToR’s collimator models are quite simple and rely on the computation of focal points in order to draw lines of response during reconstruction. If I am not mistaken, with D-SPECT, the collimators could span different angles during acquisition while the detector remains static ? If the number of angles are fixed (not continuously moving), one workaround to make it work with CASToR would be to define as many heads as number of panels*number of sweep angles, and set different collimators models for each heads. The functions allowing to convert GATE data would require quite some modifications though.

I hope this helps

Best regards,

Thibaut