[Gate-users] APLHAS AND BETAS?

William A. Dezarn wdezarn at wakehealth.edu
Wed Feb 5 17:08:45 CET 2020

You have to consider what materials and geometry you are using in your simulation. A sheet of paper will stop alphas from radioisotopes. About 2 cm of acrylic will stop betas from radioisotopes. Gammas/photons are the only particles you will observe in a standard clinical simulation. To observe anything other than photons in a SPECT detector will require very special geometries and possibly regions of vacuum. Or a particle accelerator simulation.
Hope this helps. I’m new to Gate but have been using G4 for years.

William A. Dezarn, Ph.D., DABR
Associate Professor
Department of Radiation Oncology
Wake Forest University School of Medicine
Medical Center Boulevard
Winston-Salem, NC 27157

From: Gate-users <gate-users-bounces at lists.opengatecollaboration.org> on behalf of David Boersma <david.boersma at acmit.at>
Date: Wednesday, February 5, 2020 at 10:48 AM
To: "gate-users at lists.opengatecollaboration.org" <gate-users at lists.opengatecollaboration.org>
Subject: Re: [Gate-users] APLHAS AND BETAS?

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Hello Anestis,

I am not a SPECT expert, but this sounds to me like a physics list issue. Which physics list are you using? Did you make sure that this physics list indeed includes the physics for alpha particles and nuclear decays?

The reference documentation for physics is here:

http://geant4-userdoc.web.cern.ch/geant4-userdoc/UsersGuides/PhysicsListGuide/html/index.html [geant4-userdoc.web.cern.ch]<https://urldefense.proofpoint.com/v2/url?u=http-3A__geant4-2Duserdoc.web.cern.ch_geant4-2Duserdoc_UsersGuides_PhysicsListGuide_html_index.html&d=DwMFCQ&c=yzGiX0CSJAqkDTmENO9LmP6KfPQitNABR9M66gsTb5w&r=2i7ZKTgkMJTkxL_2QRos8V8ijH8rBxqGuwj4Hyr6Pv8&m=eXfWPfAKKBR1cA8V9Dgp8ZBjxZEamTkx55uRrgrs-9E&s=HjPv03mO7l5jWMkxrNY5cBY7NzMblMsl6xxGmJT_akM&e=>

If you'd ask me to make a guess for the right list to use for your simulation, I'd pick "Shielding_EMZ". But take it with a grain of salt, because like I mentioned, I am not a SPECT expert.

Hope that helps,


Von: Gate-users <gate-users-bounces at lists.opengatecollaboration.org> im Auftrag von Anestis Nakas <A.Nakas at student.tudelft.nl>
Gesendet: Mittwoch, 5. Februar 2020 09:23:34
An: gate-users at lists.opengatecollaboration.org
Betreff: [Gate-users] APLHAS AND BETAS?

Hello all,

I am trying to take into acount alpha and beta emissions, apart from gammas, in a SPECT simulation. So far I have only gammas emitted from my source and I would like to take into acount the alphas and betas that my source emits, as well. For this purpose I have the full spectrum of emissions (gammas, alphas, betas) of the radionuclide that interests me (it is Actinium 225 actually) taken from MIRD.

However, in the GATE manual I found that this is possible for voxelized phantoms. In my study I am using a non voxelized phantom (NEMA IQ phantom), and I have sources confined in each out of six spheres, but only gamma emission so far.

Any help or suggestions are welcomed,

Best Regards,


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