[Castor-users] SPECT reconstruction

[Simon Stute]

Le 15/05/2019 à 15:14, Ferrer Ludovic a écrit :
>
> Hi Simon,
>
> Thank you for your response.
>
> So, cdf file format doesn’t need to be time sorted ?
>

In histogram mode, no, because all events (histogram bins) have the same 
time flag.
In your case, projections are histogrammed counts.

> That means that I can treat each projection sequentially and fill the 
> binary cdf file according to the format provided in the documentation, 
> doesn’it ?
>

Yes absolutely.

> I am not sure what ‘un-normalised scatter intensity’ is about and how 
> to compute this value. This relates to the question : “how do we deal 
> with projections centered in scatter windows ?”.
>

If you have projections of a scatter window, then you can use them to 
correct for scatter.
This means that you can include them as the 'un-normalised scatter 
rate', so for histogram data, you just divide the estimated scatters by 
the time of the acquisition.
'Un-normalised' means subject to the same intrinsic sensitivity of the 
detectors.
It is more related to PET where the scatters are usually obtained from a 
method that does not take non-uniformity of sensitivity into account.

> I guess also that the normalization factor embedded in 4^th position 
> is a way of calibrating images in terms of what suits your need. But 
> just a bet.
>

Again, it is more related to PET, or to pixelated SPECT detectors, but 
not to standard monolythic SPECT detectors.

> Cheers
>
> Ludovic
>
> *De :*Castor-users <castor-users-bounces at lists.castor-project.org> *De 
> la part de* Simon Stute
> *Envoyé :* mercredi 15 mai 2019 10:39
> *À :* castor-users at lists.castor-project.org
> *Objet :* Re: [Castor-users] SPECT reconstruction
>
> Hi Ludovic,
>
> This datafile converter from CASToR is indeed related to ROOT and is 
> adapted to GATE simulated data only.
>
> So you will have to build your own converter.
>
> To do so, you will have to decode the format of the original SPECT 
> data. It is usually DICOM, so easy to do, but you have to search 
> through the many DICOM header entries to get all you need.
> Then, all relevant information about the SPECT castor datafile format 
> is included in the documentation, for both binary cdf and ascii header 
> cdh files.
> You will have to create a program to do the reading, convertion and 
> writing.
>
> Cheers
> Simon
>
> Le 14/05/2019 à 23:12, Ferrer Ludovic a écrit :
>
>     Dear castors,
>
>     I would like to use castor to reconstruct SPECT images.
>
>     I understand from the documentation that you should provide a cdh
>     file along with a bunch of options. But, how this cdh file is
>     related to my acquired SPECT images is not clear.
>
>     Is this cdf file created by castor-DataFileConverter ? If yes,
>      this application is absent from the binary distribution I got
>     from internet (windows x64 version). I also compiled from sources
>     but it was also absent as a binary file. Is it related to the fact
>     that I don’t have ROOT installed in my system (windows 10) ?
>
>     Could you shed lights on this please ?
>
>     Cheers
>
>     Ludovic
>
>
>
>     _______________________________________________
>
>     Castor-users mailing list
>
>     Castor-users at lists.castor-project.org  <mailto:Castor-users at lists.castor-project.org>
>
>     http://lists.castor-project.org/listinfo/castor-users  <https://smex12-5-en-ctp.trendmicro.com:443/wis/clicktime/v1/query?url=http%3a%2f%2flists.castor%2dproject.org%2flistinfo%2fcastor%2dusers&umid=9f95c945-b8c1-4b5d-a0c0-ac9a42a15b4c&auth=5e43a6c06f9b1310984b164e6a5e1f834764f5a0-7117dbebff5bbbc7deaf473692f83a7e86369b21>
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.castor-project.org/pipermail/castor-users/attachments/20190515/5a37747b/attachment-0001.html>