[gate-users] RE: Phantom problem (Sophie Kerhoas)

[Sophie Kerhoas]

Hi Mikhail,
    It's good that you have now good results. I am surprised that this comes
from the fact that the phantom was a daughter of the world instead of the
system. It's probably due to the fact that the volume of the phantom was not
included in the system but is included in the world volume.  Geant4 don't
like the volume cross over and generate bugs when this happens....
Good simulation with Gate....
Sophie

-----Message d'origine-----
De : gate-users-bounces at lphe1pet1.epfl.ch
[mailto:gate-users-bounces at lphe1pet1.epfl.ch] De la part de Mikhail Shilov
Envoyé : jeudi 26 mai 2005 16:21
À : gate-users at lphe1pet1.epfl.ch
Objet : [gate-users] RE: Phantom problem (Sophie Kerhoas)

Ross, 

Thank you very much. That was exactly the problem. After making my
phantom an object daughter of the world it worked perfectly. Now
everything makes sense including the energy spectrum of the singles.

Sophie,

Unfortunately I don't use Root files. I read ASCII files myself with
IDL, which makes it a lot easier. In gateHits.dat file I look for
'annihil' in the 20th column  and then plot the x,y of the event.
I do something like this:

temp = ASCII_TEMPLATE('gateHits.dat')
z = READ_ASCII('gateHits.dat', template = template)

index = where( z.field20 EQ 'annihil' )

plot, z.field11(index), z.field12(index), psym=3

Mikhail A. Shilov
The Johns Hopkins University
Department of Radiology
Division of Medical Imaging Physics
Tel:  443-287-7315

On Tue, 2005-05-24 at 23:50, Schmidtlein, Ross/Sloan-Kettering
Institute
wrote:
> Hi Mikhail,
> 
> In your definition of the phantom it looks like you made it a
daughter
> of the ECAT system and not the world.  That would account for it not
> having any effect in the simulation.
> 
> ross
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