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<p>Hello Jakub,</p>
<p>Using that option (-opti SENS), your "normalization map" will
become your sensitivity image for the main reconstruction. So for
your main reconstruction, you must feed <i>castor-recon</i> with
this image using the <i>-sens</i> option (not <i>-img </i>which
is used to provide an initialization for the reconstructed image).</p>
<p>Best,<br>
Thibaut</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 27/08/2019 23:17, jbaran wrote:<br>
</div>
<blockquote type="cite"
cite="mid:7bdf639c36041a663557dba7f4bea51c@ifj.edu.pl">Dear
Castor-Users,
<br>
<br>
I have a question regarding the reconstructed images. I tried to
reconstruct GATE simulation data from my own scanner setup. The
images looks well. However, there is a problem with voxel values
and units.I performed attenuation correction (attenuation map in
cm^-1) and sensitivity correction (long list-mode acquisition with
high number of true coincidences). I prepared new normalization
map which merged attenuation and sensitivity (-opti SENS recon
option) and put that as an -img input for the main reconstruction.
What I found is that in case of uniform distributed phantom the
voxel values are quite low (i.e. 2*10^-8), however the background
values dropping down every iterations (i.e. from 10^-2 - 2nd
iteration up to 10^-34 15 iteration). I am wondering what kind of
calibration factor should I apply to get proper units i.e. number
of counts ? How should I eventually calculate that factor? Is it
somehow dependent from the iteration number?
<br>
<br>
I need it to perform NRMSD (Normalised Root Mean Square Deviation)
analysis to find the optimal number of iterations.
<br>
<br>
All the best,
<br>
Jakub
<br>
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<br>
</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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