[Gate-users] GATE 7 metastable source definition

Tue May 26 15:57:42 CEST 2020

Hi Josh,

There are a couple options for simulating gamma emissions from Tc-99m. One of which uses the ion source:
/gate/source/ [ source name ] /gps/particle ion
/gate/source/ [ source name ] /gps/ion 43 99 0 142.6832
/gate/source/ [ source name ] /setForcedUnstableFlag true
/gate/source/ [ source name ] /useDefaultHalfLife
/gate/source/ [ source name ] /setActivity 10 MBq

An alternative and speedier option, if you are not concerned about dosimetry within your source volume, would be to use a gamma source defined in the UserSpectrum:
/gate/source/ [ source name ] /gps/particle gamma
/gate/source/ [ source name ] /gps/energytype UserSpectrum
/gate/source/ [ source name ] /gps/setSpectrumFile data/energy_spectrum_Tc99m.txt
/gate/source/ [ source name ] /setForcedHalfLife 21625.848 s
/gate/source/ [ source name ] /setActivity 8.85244 MBq
Here, your energy spectrum file would look like:
# Gamma spectrum for Technetium 99m from LNE-LNHB/CEA Table de Radionucleides
# (first line is 1 0 to say it is a discrete spectrum)
# Three next lines : 89.6 keV, 140.511 keV, and 142.675 KeV
1 0
0.0896      0.000014
0.140511        0.885
0.142675        0.00023

Both configurations above would simulate a 10 MBq Tc-99m source. In the former case, you would set your activity as desired. In the latter case, you would scale your activity by the sum of all branching ratios to account only for the gamma portion of radioactivity.

Cheers,
Matthew

________________________________
From: Gate-users <gate-users-bounces at lists.opengatecollaboration.org> on behalf of Josh Knowland <jknowland at lucernodynamics.com>
Sent: May 26, 2020 10:35 AM
To: Christopher Watanabe <ge69kec at mytum.de>; gate-users at lists.opengatecollaboration.org <gate-users at lists.opengatecollaboration.org>
Subject: Re: [Gate-users] GATE 7 metastable source definition

CAUTION: The Sender of this email is not from within Dalhousie.

Gate Users,

Is there any update on this? Simulation of Tc99m without going through Mo-99 decay?

What is the best practice for this situation?

-josh

From: Gate-users <gate-users-bounces at lists.opengatecollaboration.org> On Behalf Of Christopher Watanabe
Sent: Thursday, January 30, 2020 3:53 PM
To: gate-users at lists.opengatecollaboration.org
Subject: Re: [Gate-users] GATE 7 metastable source definition

Hi all,

I was wondering, given that the original post here was 5 years ago, whether methods now exist for simulating the metastable Tc99m, without simulating the Mo-99 decay scheme. This, for a Tc99m SPECT imaging simulation.

I realize in the GATE examples, this is simulated using a pure gamma, but I’m interested in checking the dose, minimal though it may be, of tissue as well.

Thank you!

Chris

/----------------------------------------------------------------------------------------------------------

Hi,

you should take Mo-99, i.e. Z=42, A=99 instead, since Tc-99m

is part of the Mo-99 decay scheme. I have just tried it with

the Spectro-example of EduGATE and it gives a useful spectrum!

Also, if you use the physicslist mechanism for the physical processes you need to add:

/gate/physics/addPhysicsList emstandard

/gate/physics/addProcess RadioactiveDecay

Hope this is helpful for you!

Kind regards,

Uwe Pietrzyk

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Diplom-Physiker

Institut für Neurowissenschaften und Medizin / INM-4

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On 30 Jan 2015, at 21:17, Xinchi Hou <monicaxinchi at gmail.com<http://lists.opengatecollaboration.org/mailman/listinfo/gate-users><mailto:monicaxinchi at gmail.com<http://lists.opengatecollaboration.org/mailman/listinfo/gate-users>>> wrote:

Dear Gate-users,

I am using GATE 7 for SPECT simulations. For some reason, GATE 7 seems can not recognize metastable source by defining an ion source (shows below,Tc-99m as an example), which can be successfully run by GATE 6.1:

/gate/source/SourceTC99m/gps/particle ion

/gate/source/SourceTC99m/gps/ion 43 99 0 142.6833

/gate/source/SourceTC99m/gps/monoenergy 0 keV

/gate/source/SourceTC99m/setForcedUnstableFlag true

/gate/source/SourceTC99m/setForcedHalfLife 21640 s

I know we can define 140keV gamma as a source instead of using ion source. However, I need to use many of other metastable isotopes as sources which usually have multiple gamma energies for each of them.

I really appreciate if somebody could share his/her experience on similar problems.

My best regards,

Monica

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