[Castor-users] Attenuation correction and normalization for list-mode reconstruction

[tmerlin]

Dear Zipai,


I advice to proceed as Simon suggested, but just for information there 
is a way to compute the ACFs with /castor-GATERootToCastor/ using the 
/-atn/ option. They will be incorporated in the generated CASToR 
datafile. The projector must be the same that the one used for 
reconstruction.


Best,

Thibaut


On 16/05/2022 14:08, STUTE Simon wrote:
>
> Hi Zipai Wang,
>
>
> 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.
>
>
> To compute the attenuation coefficients, I personally use the 
> following database
>
> https://physics.nist.gov/PhysRefData/Xcom/html/xcom1.html
>
> 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.
>
>
> 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".
>
>
> Simon
>
>
> ------------------------------------------------------------------------
> *De :* Castor-users <castor-users-bounces at lists.castor-project.org> de 
> la part de Zipai Wang <zipai.wang at stonybrook.edu>
> *Envoyé :* lundi 18 avril 2022 22:01
> *À :* castor-users at lists.castor-project.org
> *Objet :* [Castor-users] Attenuation correction and normalization for 
> list-mode reconstruction
> Dear CASToR users and developers,
>
> 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.
>
> 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.
>
> 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?
>
> 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?
>
>
> Thank you very much for your help!
> -- 
> Zipai Wang
> Biomedical Engineering PhD student
> Stony Brook University
>
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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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