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<p>Hi Maxime,</p>
<p>Thank you for the work. There was indeed mismatches with the
positioning in the layers. Additionally, even with a single layer
the code assumes that the rsector face corresponds to the detector
faces, which is not necessarily true. I made some quick fixes
(code in attached), which should correct the issue. They will be
included in the next code update.</p>
<p>Many thanks,<br>
Thibaut M.<br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 31/03/2019 17:12, Maxime Toussaint
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:5b98272f-d1d5-4dcb-7600-f003154a3ee7@usherbrooke.ca">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<tt>Greetings,<br>
<br>
We discovered a mismatch between the LUT generated by CASToR in
castor-recon and Gate detector center position for a scanner
defined as a Cylindrical Pet with DOI layer. After some
investigation, the mismatch was shown to be mostly radial and
due to an "error" in defining the scanner layer radius.<br>
<br>
From our understanding, Gate defines a detector position
relative to the detector center while CASToR defines it, at
least temporally, relative to its front face. While they can be
made equivalent, the current conversion of Gate "layer
translation" to "scanner layer radius" seems to be at fault.
Currently, the layer translation, defined in Gate relative to
the center of its Parent, is applied directly to the "layer
front face radius" which is not equivalent.<br>
<br>
Following this email, we propose a solution which work for our
case. However, it is not perfect. For example, one of its
limitation, if my understanding is correct, is that it assume
that the face of the first DOI layer correspond to
"block_pos_{X/Y}" which is "near enough" but not exactly true
most of the time.<br>
<br>
Best,<br>
Maxime Toussaint<br>
<br>
<br>
<br>
In src/management/gDataConversionUtilities.cc<br>
<br>
</tt>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);"> <font color="#009900">+
if ( l == 0)<span><br>
</span></font>
<div><font color="#009900">+ {<br>
</font></div>
<div><font color="#009900">+
vec_scanner_radius.push_back( toString(scanner_radius) );<br>
</font></div>
<div><font color="#009900">+ }<br>
</font></div>
<div><font color="#009900">+ else<br>
</font></div>
<div><font color="#009900">+ {<br>
</font></div>
<div><font color="#009900">+
vec_scanner_radius.push_back(
toString(stod(vec_scanner_radius[l-1]) +
layers_size_depth[l-1]) );<br>
</font></div>
<div><font color="#009900">+ }</font><br>
</div>
<font color="#ff0000">- vec_scanner_radius.push_back(
toString(scanner_radius+layers_positions[l][0]) );</font></div>
<br>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<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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