[gate-users] ECAT scanner sinogram output

[Schmidtlein, Ross/Sloan-Kettering Institute]

Hi Uday,

There are different formats available to store LOR's.  The Gate ECAT
output is arranged in N/2 x N/2 matrices (sinograms) that are in turn
placed in a m x m matrix (where m = the total number of rings in your
particular scanner) creating a block matrix structure (Michelogram).
The N/2 x N/2 sinograms represent the N/2 projection planes each
containing N/2 radial bins.  Note that this system in Gate uses
interlacing to half the number of projection planes and double the
number of radial bins (N->N/2, and N/4->N/2, for projection and radial
bins respectively). This structure is repeated for each ring pair
(ring1,ring2).  The book, "The Theory and Practice of 3D PET", edited by
Bendriem and Townsend give a brief description of this format.

Hope this helps,

ross

-----Original Message-----
From: gate-users-bounces at lphe1pet1.epfl.ch
[mailto:gate-users-bounces at lphe1pet1.epfl.ch] On Behalf Of Uday Tipnis
Sent: Friday, February 25, 2005 1:59 PM
To: gate-users at lphe1pet1.epfl.ch
Subject: [gate-users] ECAT scanner sinogram output



Hi all,

Could someone please help me to interpret the 2D sinogram output 
generated by the ECAT scanner system? If a scanner has m crystal rings 
with N crystals each, then the sinograms are N/2 x N/2 x m*m in 
dimension. How does the projection data get classified into N/2 bins and

m*m slices? Please help.

Thanks in advance,

Uday

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