Construction of Castor histogram data file

Hi Castor developers and users,

A few moths ago I got the code for saving the forward projections (castor-proj) and I have used this a lot to generate PET-data so far.
I try to manually put Gaussian blur over the sinogram data to simulate the poorer resolution of PET data by PSF. I want to do this by putting a Gaussian blur on every single 2D-sinogram. In order to do this, I need to understand how the sinogram datafile is constructed and this has not become very clear to me yet. I know that every 16 bytes (for my data) describe one bin in the sinogram, but I don’t know in what order this dat is stored and whether I can properly separate the sinograms here to apply Gaussian blur.
Is it possible to provide more clarity on how the sinogram datafiles are constructed when formed with castor-proj?

Many thanks in advance,

Hi Inge,

To be generic and to allow for any possible geometry, no assumption are made.

This means that CASToR is using histograms and not sinograms, because sinograms are based on a specific geometry organisation.

The current solution for you is to use a blur in the image space.

In the future, a generic sinogram-based virtual scanner will be added in CASToR, so that for any modality (PET, SPECT or CT), a scanner could be described as a sinogram instead of describing the detector arrangement.

In this case, sinogram PSF blur will be allowed.



Hi Simon,

Thank you very much for your response.
I understand, then I will blur the images during reconstruction.

Alle the best,