[Gate-users] Michelogram extraction from ROOT input

[Vincenzo Eduardo Padulano]

Hello Gate users,
I am simulating a cylindricalPET system and storing data in ROOT file
format. I have found lately Schmidtlein's code to read coincidences from
the ROOT TTree and generate corresponding Michelogram. I am encountering
very strange behaviour and can't seem to understand whether it is due to
the simulation, the code, or whatever else. Trying to keep it simple, I am
now simulating a point source in the central axial plane . Still I get
strange output from the code. I will now include the parameters that I have
changed in the code, according to my PET scanner specifications:

// DLS Parameters
#define  N_RINGS               45 // DLS: Number of rings
#define  N_SEG                 89 // DLS: Number of segments (2 N_RINGS - 1)
#define  N_DET                448 // DLS: Detectors per ring
#define  S_WIDTH              325 // DLS: Number of radial sinogram bins
//#define  N_RSEC                28 // DLS: Number of resector
//#define  N_MODULE               20 // DLS: Number of modules (2x3)
#define  N_MOD_xy               4 // DLS: Number of tangential modules
#define  N_MOD_z                5 // DLS: Number of axial modules
//#define  N_SUBMOD               1 // DLS: Number of submodules (1x1)
#define  N_SMOD_xy              1 // DLS: Number of tangential submodules
#define  N_SMOD_z               1 // DLS: Number of axial submodules
//#define  N_CRYSTAL             36 // DLS: Number of crystals (6x6)
#define  N_CRY_xy               4 // DLS: Number of tangential crystals
#define  N_CRY_z                9 // DLS: Number of axial crystals
#define  MAX_D_RING            1 // DLS: Maximum ring difference
//#define  N_PLANES             265 // DLS: Total number of sinograms
//#define  FOV                  550 // DLS: Width of the FOV (mm)
//#define  SLICES_PER_FOV        35 // DLS: Number of slices per FOV
#define  USE_OFFSET             0 // DLS: On/Off use of offset
#define  OFFSET               499 // DLS: Sets initial sinogram angle

I will also attach an image representing the supposed sinogram at the
center of Z axis (Z=0) . If anybody has ever encountered similar behaviour
and has the knowledge on how to overcome this situation, it would be
greatly appreciated.
Kind regards,
Vincenzo
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