Hello everyone,
I am trying to create .geom file from a .mac file for PET scanner system. In the .geom file created, I would like to know how the voxels number transaxial, voxels number axial, field of view transaxial, field of view axial are being calculated.
DigiPET.geom (1.7 KB)
Hello Kajal,
F.O.V variables are arbitrary computed as scanner_radius(mm)**/4 for the transaxial component, and the axial dimension (mm) of the rsector/block for the axial component. The transaxial/axial number of voxels are calculated from these values in order to get (large) isotropic 4mm voxels.
The sole purpose of these variables is to be used as default for reconstruction dimensions/voxel sizes when using this scanner, in the case no dimensions have been initialized in command-line options. In practice, they are overwritten by the parameters entered in command line options (-dim for number of voxels, -fov /-vox for field of view and voxel dimensions initializations ).
Best regards,
Thibaut
Hello,
Thank you for the detailed explanation. I am having troubles to reconstruct an image for a cylindrical PET system simulated using Gate. I am generating .geom file and .cdh and .cdf files (attached in this email) for my .mac file and for the output root file. But the image generated has some problem (see the screen-shot below). Please guide me where I am going wrong.
Thank you very much for all your support.
Regards,
Kajal
DigiPET.geom (1.7 KB)
kj_CstrProj.Cdf (13.1 KB)
kj_CstrProj.Cdh (216 Bytes)
Hello Kajal,
I can’t really tell what could be wrong without knowing what was in the simulation. From your data and the reconstructed image, it looks like you simulate a line source at 1;-1 cm. Statistics are very low though (1k counts), so it’s difficult to say if there was something wrong with the conversion or geometry. It doesn’t look like there are issues with the geometry from the sensitivity image though. Perhaps you could check what do you get with a simulation with higher statistics ?
Best regards,
Thibaut
