[Gate-users] Implementation of the NEMA Image Quality source

Wed Feb 14 19:16:40 CET 2018

Dear Ane,
Thank you very much for your help.
Happily, I have managed to implement the NEMA Image Quality phantom.
Following archive message written by Kaiyang Li in 2012 was very useful: [Gate-users] cold area and "forbid" usage in GATE
These are advices from the message:
*1* cold area can not be overlapping with other volumes in the world (source is not a volume, so cold area can overlap with source). If you want to simulate a cold area in a water phantom. This cold area should be the daughter of the water phantom, not the daughter of the world.*2* initializing step should run after defining the cold area, before defining the source.*3* if forbid success, there should be two lines indicated by terminal (if you debug your codes one line by one line in the terminal) "Confirming activity forbidden in volume 'xxxx' Activity forbidden in volume 'xxx' confirmed"*4* The name of the cold area should longer than 5 characters.

Dear GATE Developers, please add these suggestions to the wiki.
In order to implement the source I had to modify the phantom macro (maybe it should be updated in the repository on github?). I had to change the name of volume IBox into name longer than 5 characters (boxinterior). I had to also add the cold volume NEMA_IQ_cold.According to suggestion 1, cold volumes cannot overlap. Happily it is possible to use elements of the phantom (which are not overlapping) as cold areas.
Sources activities were calculated using the attached spreedsheet assuming that the background activity concentration is 5.3 kBq/cc.
You can find my phantom and source in attachment.
These macros and their updates will be also available in the github repository: https://github.com/JPETTomography/j-pet-gate-tools 
Best regards,Paweł Kowalski,National Centre for Nuclear Research

    11:30 środa, 2018-2-14, Ane Etxebeste <fplico817 at gmail.com> napisał(a):

Dear Pawe Kowalski,

I have not looked carefully into your macro.
But I have seen that you have applied Forbid command several times to
the same volume without specifying it.

For example, you have the following lines in your macro.
 /gate/source/IBox_hot/gps/Forbid              sphere22
 /gate/source/IBox_hot/gps/Forbid              sphere22in
 /gate/source/IBox_hot/gps/Forbid              fill22
 /gate/source/IBox_hot/gps/Forbid              fill22in
 /gate/source/IBox_hot/gps/Forbid              sphere28
 /gate/source/IBox_hot/gps/Forbid              sphere28in
 /gate/source/IBox_hot/gps/Forbid              fill28
 /gate/source/IBox_hot/gps/Forbid              fill28in

In this case you have applied Forbid command 8 times to IBox_hot volume.
Try adding the following command to specify the number of cold volumes
you want to create inside IBox_hot volume
 /gate/source/IBox_hot/dump 8

I hope this helps you.
Best regards,
Ane Etxebeste

Quoting "Pawe  Kowalski" <pawkowalski at yahoo.com>:

Dear GATE users,
I am currently working on simulations of the NEMA characteristics of
a PET scanner.
While it is quite easy to implement phantoms and sources for spatial resolution, scatter fraction and sensitivity characteristics,  it is challenging to implement the NEMA Image Quality phantom and the source.
Happily, the macro for the phantom may be found at Github repository
in path:
GateContrib-master/imaging/PhantomSource/Analytical_Phantom/NEMA_IEC_2001.macUnfortunatelly the phantom seems to be useless without the dedicated
source.
I have searched for many archive messeges from gate-users mailing list and I have found no working macro with implementation of this source. It is very strange for me because it seems that the Image Quality is a quite important characteristic and many people try to perform such simulations.
Has noone really managed to implement the source for the NEMA IQ phantom?
If someone managed to do it, please make it public.
Using some examples that may be found in the network, I have been
trying to implement this source by myself. Unfortunatelly I have
some problems that I cannot solve (and it seems that they were not
solved by the people that tried to implement the phantom in previous
years).
In the attachments there are my macros for the phantom, the source,
and the test source which is a part of the whole source.
Because of the fact that it is not possible to use gps source with volume which is an angular part of the cylinder (for the phantom there are commands: setPhiStart and setDeltaPhi) I have tried to implement parts of the IQ source using cylindrical sources and cold regions. Unortunatelly, it seems that the Forbid command does not work as it should.There are some generations in regions, in which theoretically they should not appear.
The macro source_test.mac is a part of the source. The generations
should be only between angles 270 and 360 but they are also in the
rest of the region. I attach 2d histogram of sourcePosX and
sourcePosY as a proof (for simulation with source_test.mac).
What am I doing wrong? Please take a look at my macros. Maybe
someone will know how to correct them in order to make them proper.
I would be very grateful for your help and for any suggestions that
would lead to the solution.
Best regards,Pawe? Kowalski,National Centre for Nuclear Research

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