[Castor-users] attenuation correction in CASToR TOF recon image

[tmerlin]

Dear Xin Zhao,

Indeed the output you get is strange, but I don't see anything wrong in 
your datafile header or command line options.

Do you get the same output (no attenuation) when you try to reconstruct 
the tof dataset without tof (i.e delete the tof related line in the 
datafile header) ? Did you try to reconstruct with different time 
resolution to check if this has an impact on the observed attenuation ?

Best,
Thibaut

On 06/06/2022 05:18, 赵鑫 wrote:

> Dear CASToR developers and users,
>
>     We simulated a cylindrical phantom using GATE and extract time and crystalID information from ROOT file. We organized two groups of Cdh&Cdf files followed CASToR input datafile format, for non-TOF and TOF reconstruction respectively. Two recon images are shown in "non-TOF recon.png" & "141ps TOF recon.png" images as presented in the attachment. But I found out that there is almost no attenuation that can be seen in the "141ps TOF recon.png" image compared to "non-TOF recon.png". From the image profiles in "profile.png", it can be seen from the non-TOF recon image that the central area has obvious count attenuation, while the TOF recon image shows no sign of attenuation. I am curious about why because I applied no additional "-atn XXXX.hdr" attenuation correction when running castor-recon for TOF reconstruction. 
>
>     The CASToR recon command of 141ps TOF recon is: "castor-recon -df /home/castor/BrainPET_IEC_F18_3sphere1_5p3c_TOF141p42ps.Cdh -opti MLEM -it 10:9 -proj joseph -conv gaussian,1.7,1.7,3::psf  -dim 630,630,250  -vox 0.3225,0.32255,0.3225   -dout /home/castor/img/BrainPET_IEC_F18_3sphere1_37and22and13_5p3concent_510s_TOF141p42ps_20220605 -th 0". The TOF recon datafile  header "BrainPET_IEC_F18_3sphere1_5p3c_TOF141p42ps.Cdh" is also submitted in the attechment.
>     Do you have any idea why attenuation seems not obvious in the TOF recon image from castor-recon?  Can you point out what went wrong with my TOF Recon? Any advice and suggestion will be greatly appreciated. Thank you! 
>
>
> All the best,
> Xin Zhao
>
>
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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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