<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi Marta,<div class=""><br class=""></div><div class="">here in the documentation you can find the different physics lists, and you are right it is recommend to use physics builder.</div><div class=""><a href="https://opengate.readthedocs.io/en/latest/setting_up_the_physics.html" class="">https://opengate.readthedocs.io/en/latest/setting_up_the_physics.html</a></div><div class=""><br class=""></div><div class="">If you need high precision for all the processes, for example for dosimetry applications, it is recommended to use either emlivermore or emstandard_opt4:</div><div class=""><pre style="font-family: Consolas, Menlo, "DejaVu Sans Mono", "Bitstream Vera Sans Mono", monospace; font-size: 0.9em; background-color: rgb(238, 238, 238); padding: 7px 30px; margin-top: 15px; margin-bottom: 15px; line-height: 1.3em; color: rgb(62, 67, 73); font-variant-ligatures: normal; orphans: 2; widows: 2; background-position: initial initial; background-repeat: initial initial;" class=""><span class="o" style="color: rgb(88, 40, 0);">/</span><span class="n" style="color: rgb(0, 0, 0);">gate</span><span class="o" style="color: rgb(88, 40, 0);">/</span><span class="n" style="color: rgb(0, 0, 0);">physics</span><span class="o" style="color: rgb(88, 40, 0);">/</span><span class="n" style="color: rgb(0, 0, 0);">addPhysicsList emlivermore</span></pre><div class="">or</div></div><div class=""><pre style="font-family: Consolas, Menlo, "DejaVu Sans Mono", "Bitstream Vera Sans Mono", monospace; font-size: 0.9em; background-color: rgb(238, 238, 238); padding: 7px 30px; margin-top: 15px; margin-bottom: 15px; line-height: 1.3em; color: rgb(62, 67, 73); font-variant-ligatures: normal; orphans: 2; widows: 2; background-position: initial initial; background-repeat: initial initial;" class=""><span class="o" style="color: rgb(88, 40, 0);">/</span><span class="n" style="color: rgb(0, 0, 0);">gate</span><span class="o" style="color: rgb(88, 40, 0);">/</span><span class="n" style="color: rgb(0, 0, 0);">physics</span><span class="o" style="color: rgb(88, 40, 0);">/</span><span class="n" style="color: rgb(0, 0, 0);">addPhysicsList emstandard_opt4</span></pre><div class="">But…</div></div><div class=""><br class=""></div><div class="">When simulating SPECT, you may only be interested in photons (X-ray, gammas) reaching your detector </div><div class="">so you may want to have only processes related to photons in your physics list. </div><div class="">This is possible ONLY if you build your own physics list with macro commands such as (not the addPhysicsList) :</div><div class=""><pre style="font-family: Consolas, Menlo, "DejaVu Sans Mono", "Bitstream Vera Sans Mono", monospace; font-size: 0.9em; background-color: rgb(238, 238, 238); padding: 7px 30px; margin-top: 15px; margin-bottom: 15px; line-height: 1.3em; color: rgb(62, 67, 73); font-variant-ligatures: normal; orphans: 2; widows: 2; background-position: initial initial; background-repeat: initial initial;" class=""><span class="o" style="color: rgb(88, 40, 0);">/</span><span class="n" style="color: rgb(0, 0, 0);">gate</span><span class="o" style="color: rgb(88, 40, 0);">/</span><span class="n" style="color: rgb(0, 0, 0);">physics</span><span class="o" style="color: rgb(88, 40, 0);">/</span><span class="n" style="color: rgb(0, 0, 0);">addProcess</span> <span class="p" style="color: rgb(0, 0, 0); font-weight: bold;">[</span><span class="n" style="color: rgb(0, 0, 0);">Process</span><span class="p" style="color: rgb(0, 0, 0); font-weight: bold;">]</span> <span class="p" style="color: rgb(0, 0, 0); font-weight: bold;">[</span><span class="n" style="color: rgb(0, 0, 0);">Particle</span><span class="p" style="color: rgb(0, 0, 0); font-weight: bold;">]</span></pre><div class="">Your SPECT simulation will be faster that way but you should be really careful to not forget something that might impact the result. </div><div class="">I only recommend this to advanced users.</div></div><div class=""><br class=""></div><div class="">I hope it helps.</div><div class=""><br class=""></div><div class="">Best regards,</div><div class=""> Maxime Chauvin</div><div class=""><div><br class=""><blockquote type="cite" class=""><div class="">On 24 Apr 2020, at 00:56, Marta Coelho <<a href="mailto:martinhaonline109@gmail.com" class="">martinhaonline109@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Hi GATE users,<div class=""><br class="">I installed the VGATE 8.2 platform. and I have doubts about the physical part of the script to simulate the SPECTHead system.<br class="">The manual says "Up to now, physic lists were set in GATE according to macro files containing list of command to add physical processes. From GATE Version 7.0, we highly recommend to switch to the" physic list builder "mechanism. The physic-list builders are provided by the Geant4 community. To use a builder, use the “addPhyslicsList”.<br class="">My question is: What is the best physics lists for simulating a SPECT system? <div class=""><br class="">Thank you for your attention and I look forward to an answer.<br class=""></div></div></div>
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