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    <p>Hi,</p>
    <p><br>
    </p>
    <p>Just to add to Simon's answer:</p>
    <p><br>
    </p>
    <p>If you only recovered true coincidences from the GATE simulation
      data, and if you are using list-mode data, then with the -atn
      option you can provide an (interfile) image containing the
      attenuation coefficient value (in cm-1) to correct for attenuation
      during reconstruction. Attenuation correction factors will be used
      as multiplicative correction factors during the computation of the
      sensitivity image (which is calculated first when you launch the
      reconstruction), so the sensitivity image will include correction
      for attenuation. <br>
    </p>
    <p><br>
    </p>
    <p>Best,<br>
    </p>
    <p>Thibaut<br>
    </p>
    <p><br>
    </p>
    <p><br>
    </p>
    <div class="moz-cite-prefix">On 20/01/2020 10:27, STUTE Simon wrote:<br>
    </div>
    <blockquote type="cite" cite="mid:1579512422242.45416@chu-nantes.fr">
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      <p>Hi,</p>
      <p><br>
      </p>
      <p>I may be wrong but Chang's method is for SPECT.</p>
      <p><br>
      </p>
      <p>For PET, you have to compute the attenuation correction factor
        for each event also, and add this information in the datafile.<br>
      </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 김연경 <a class="moz-txt-link-rfc2396E" href="mailto:dusrud026@gmail.com"><dusrud026@gmail.com></a><br>
            <b>Envoyé :</b> lundi 20 janvier 2020 09:43<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>; Thibaut
            Merlin<br>
            <b>Cc :</b> Yong Choi<br>
            <b>Objet :</b> [Castor-users] Attenuation correction for PET
            image</font>
          <div> </div>
        </div>
        <div>
          <div dir="ltr"><font face="arial, sans-serif" color="#000000">Dear
              CASToR users<br>
              <br>
              I obtained the image of the GATE simulation data using the
              castor program. <br>
              <br>
            </font>
            <div><font face="arial, sans-serif" color="#000000">I would
                like to ask the confusing part of applying the
                attenuation correction to the acquired image. The data
                is list mode.<br>
                <br>
              </font></div>
            <div><font face="arial, sans-serif" color="#000000">if I
                enter the same image as the phantom size with
                attenuation coefficient value into the -atn option, will
                the attenuation factor be calculated within the caster
                program's code and corrected for the image?<br>
                <br>
              </font></div>
            <div><font face="arial, sans-serif" color="#000000">If the
                method described above is correct, does the program use
                the method of Chang's multiplicative?<br>
                <br>
              </font></div>
            <div><font face="arial, sans-serif" color="#000000">Any help
                I would really appreciate it.
                <br>
                <br>
                Best regards<br>
                --</font>
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                <div dir="ltr">
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                        <div dir="ltr">
                          <p><font face="tahoma, sans-serif"
                              color="#666666">YEONKYEONG KIM</font></p>
                          <p><font face="tahoma,sans-serif"
                              color="#666666">Molecular Imaging
                              Research&Education Laboratory (MIRE
                              Lab)<br>
                              Department of Electronic
                              Engineering,Sogang University</font></p>
                          <p><font face="tahoma,sans-serif"
                              color="#666666">803, Ricci Hall(R 803),
                              Sogang University<br>
                              35 Baekbeom-ro, Mapo-gu, Seoul, South
                              Korea 04107<br>
                              Mobile : +82-10-9996-3644<br>
                              Email : <a
                                href="mailto:dusrud026@gmail.com"
                                target="_blank"
                                style="color:rgb(17,85,204)"
                                moz-do-not-send="true">dusrud026@gmail.com</a></font></p>
                        </div>
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              <br>
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src="https://mailtrack.io/trace/mail/38445b201111d2c2a6f517e59a1f3d0bec142efc.png?u=5192502"
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      <pre class="moz-quote-pre" wrap="">_______________________________________________
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</pre>
    </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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