[Castor-users] Reconstructed images' units

[tmerlin]

Hello Jakub,

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 /castor-recon/ with this image using the 
/-sens/ option (not /-img /which is used to provide an initialization 
for the reconstructed image).

Best,
Thibaut


On 27/08/2019 23:17, jbaran wrote:
> Dear Castor-Users,
>
> 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?
>
> I need it to perform NRMSD (Normalised Root Mean Square Deviation) 
> analysis to find the optimal number of iterations.
>
> All the best,
> Jakub
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> Castor-users at lists.castor-project.org
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-- 
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

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