[Gate-users] How to convert the photon into wavefront (X-ray's partical property -> X-ray's wave optical property) ?

[Simon Rit]

Hi,
Thanks for the reference. After a quick glance, it looks similar to what is
attempted in the FixedForcedDetectionActor. Primary should give you the
fluence and Fresnel the one with phase contrast. Can you elaborate on why
it does not look like the fluence to you? Be careful that this is
deterministic so if you set 1 primary photon in your simulation, you'll get
the probability to get a photon in each pixe, i.e., a very low number.
1. You cannot use the actor to store the remaining energy of each photon
but you can do that with a PhaseSpaceActor. Note that there is not even the
notion of photon here since a deterministic process.
2. The files containing FixedForcedDetectionActor are the ones doing the
job. Check this code
<https://github.com/OpenGATE/Gate/blob/develop/source/digits_hits/src/GateFixedForcedDetectionActor.cc#L1165-L1211>
to look at what's done. What you want is the delta image, which you should
be able to write to disk with materialDeltaFilename.
I hope this helps,
Simon

On Fri, Jun 14, 2019 at 3:01 PM Jianbing <dongjbstrong at 163.com> wrote:

> Here are the refrenced phase-contrast simulation method:
> http://journals.iucr.org/s/issues/2014/03/00/hf5246/hf5246.pdf
>
> At 2019-06-14 20:53:17, "Jianbing" <dongjbstrong at 163.com> wrote:
>
> Dear Gaters:
>       I want to use GATE to simulate X-ray phase-contrast imaging, which
> is based on X-ray' s wave property. Within my knowledge, There are two way
> to implement phase-contrast simulation:
>       1) "XrayBoundary" physical process. This process is based on Snell's
> law, and it is simulation of the particle property of X-ray;
>       2) "Fixed Forced Detection CT with Fresnel phase contrast". This
> Actor only suports voxelized volume. And the 'fresnel' result and the
> 'primary' result seems to have nothing to do with the number of photons,
> which is not consistent with real physical process.
>       Some people have combined Monte-carlo with Matlab to simulate
> Phase-contrast imaging
> <http://journals.iucr.org/s/issues/2014/03/00/hf5246/hf5246.pdf>.
>       The key point is to store the path integral of the real part δ
> (complex refractive index, n = 1 - δ + iβ) in the trajectory when each
> photon passing through the material,  and store its remaining energy.
>
>       Here are my questions:
>       1. How could I use "Phase space Actor" to store the remiaing Energy
> of each photon which has passing through the object?
>       2. How could I store the path integral of the real part δ of the
> complex refractive index? Which source file should I modify to realize this
> function?
>
>       Any help will be appreciated, thanks in advance.
>
>      Sincerely,
>      Jianbing
>
>
>
>
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