[gate-users] minSectorDifference

[Sophie Kerhoas]

Bonjour Corinne,
 The minSectorDifference concern always the volume attached to the first
level of a system and will be used by the coincidence sorter to valid or
not a coincidence.
For a cylindricalPET system, the volume which is concerned is the one
attached to the rsector and for a ecat system, it is the block.
So it doest not depend and the setDepth you declared for the readout. It
is hard coded in the Gate CoincidenceSorter.cc.
The initialization is done at 2 int the constructor of the class:
  m_minSectorDifference(2)
and the test is done in the class IsForbiddenCoincidence.
Hope this help,
it is probably not enough clear in the userguide and should be perhaps
rewritten.

bonne journee,

sophie

On Mon, 2004-08-30 at 22:35, Corinne J Groiselle wrote:
> Hi,
> 
> I have a question about the following command in the GATE digitizer
> because I am not sure I really understand what it means:
> 
> To exclude false coincidence coming from the same particle that
> scattered from a block to an adjacent block, a test is done on the
> proximity of the two blocks forming the coincidence event. By default,
> the coincidence is valid only if the difference in the block numbers
> is greater than two. This rejection can be adapted to a more specific
> analysis by using the command:
> /gate/digitizer/Coincidences/minSectorDifference [number]
> 
> First of all, what does block mean? It's not one of the key words of any of the PET systems description (rsector, module, submodule, crystal, layer)?
> Is it used for module or rsector depending on how the level of readout is defined with the command: /gate/digitizer/Singles/readout/setDepth 1 ?
> a) In case we chose setDepth 1, does it mean that the coincidence will be kept only if rsectorID1 - rsectorID2 >= 2?
> b) In case we chose setDepth 2, does it mean that the coincidence will be kept only if moduleID1 - moduleID2 >= 2?
> 
> If a), I understand that the rejection is radially dependent on the position of the block (there is only 1 rsector in the axial direction) but if b), the rejection is axially dependent on the position of the block (as the modules are numbered per rsector).
> 
> Could someone help me and tell me if I am correct of not?
> 
> Thanks a lot,
> -- Corinne
> 
> 
> ______________________________________________________________________
> Corinne J. Groiselle, PhD
> 
> Research instructor
> 
> Division of Nuclear Medicine / Department of Radiology 
> University of Massachusetts Medical School 
> 55 Lake Avenue North
> Worcester, MA 01655
> USA
> 
> phone: (508)-856-6123 - fax: (508)-856-4572
> e-mail: Corinne.Groiselle at umassmed.edu
> professional homepage: http://users.umassmed.edu/corinne.groiselle
> personal homepage: http://corinne.groiselle.free.fr
> 
> 
> 
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