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<p>Dear Zipai,</p>
<p><br>
</p>
<p>I advice to proceed as Simon suggested, but just for information
there is a way to compute the ACFs with <i>castor-GATERootToCastor</i>
using the <i>-atn</i> option. They will be incorporated in the
generated CASToR datafile. The projector must be the same that the
one used for reconstruction. <br>
</p>
<p><br>
</p>
<p>Best,</p>
<p>Thibaut</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 16/05/2022 14:08, STUTE Simon wrote:<br>
</div>
<blockquote type="cite" cite="mid:1652702929368.5423@chu-nantes.fr">
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<p>Hi Zipai Wang,</p>
<p><br>
</p>
<p>When you use a normalization datafile to guide the computation
of the sensitivity image, you can input attenuation correction
factor in the normalization datafile but you can still simply
supply an attenuation image with the option "-atn". Both are
compatible.</p>
<p><br>
</p>
<p>To compute the attenuation coefficients, I personally use the
following database
</p>
<p><a
href="https://physics.nist.gov/PhysRefData/Xcom/html/xcom1.html"
moz-do-not-send="true">https://physics.nist.gov/PhysRefData/Xcom/html/xcom1.html</a></p>
<p>It is very convenient, you just supply the different compounds
of the material from the GATE material database, ask for an
energy, and get the attenuation factor.</p>
<p><br>
</p>
<p>Then you can build an image where you replace each label of
your phantom by the attenuation factor in cm-1, and this is what
you supply to castor using the option "-atn".</p>
<p><br>
</p>
<p>Simon</p>
<p><br>
</p>
<div style="color: rgb(33, 33, 33);">
<hr tabindex="-1" style="display:inline-block; width:98%">
<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt"
face="Calibri, sans-serif" color="#000000"><b>De :</b>
Castor-users
<a class="moz-txt-link-rfc2396E" href="mailto:castor-users-bounces@lists.castor-project.org"><castor-users-bounces@lists.castor-project.org></a> de la
part de Zipai Wang <a class="moz-txt-link-rfc2396E" href="mailto:zipai.wang@stonybrook.edu"><zipai.wang@stonybrook.edu></a><br>
<b>Envoyé :</b> lundi 18 avril 2022 22:01<br>
<b>À :</b> <a class="moz-txt-link-abbreviated" href="mailto:castor-users@lists.castor-project.org">castor-users@lists.castor-project.org</a><br>
<b>Objet :</b> [Castor-users] Attenuation correction and
normalization for list-mode reconstruction</font>
<div> </div>
</div>
<div>
<div dir="ltr">Dear CASToR users and developers,
<div><br>
</div>
<div>I have simulated a digital phantom in GATE and
reconstructed the GATE list-mode using CASToR. In order to
perform the normalization I manually calculated the
normalization factors and fed the normalization datafile
into the CASToR for the calculation of Sensitivity image.</div>
<div><br>
</div>
<div>In this case, in order to apply the attenuation
correction, I believe I need to calculate the attenuation
coefficient for each LORs and feed it within the
normalization datafile. However this is
not straightforward for me because the phantom contains
multiple types of material and tissues. </div>
<div><br>
</div>
<div>So my question is: 1. I know we can feed atn image to
CASToR during the reconstruction, but in this way how can
I apply the normalization?</div>
<div><br>
</div>
<div>2. Can the CASToR generate the atten coefficient and
output the information so that I can combine it with the
norm factors to form the datafile?</div>
<div><br>
</div>
<div> <br clear="all">
<div>Thank you very much for your help!</div>
-- <br>
<div dir="ltr" class="gmail_signature">
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">Zipai Wang</div>
<div dir="ltr">Biomedical Engineering PhD
student
<div>Stony Brook University </div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<br>
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<pre class="moz-quote-pre" wrap="">_______________________________________________
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</blockquote>
<pre class="moz-signature" cols="72">--
Thibaut MERLIN -- PhD
Docteur en Imagerie Médicale au Laboratoire de Traitement de l'Information Medicale (LaTIM - INSERM UMR 1101)
Institut Brestois de recherche en Bio-Santé (IBRBS)
12 Avenue Foch, 29200 Brest, FRANCE
Tel: 06.75.12.24.90</pre>
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