[gate-users] Image Reconstruction of Gate output

[Kris Thielemans]

Hi Long

> 
> It seems that I have mistake the sinogram width (angle 
> position) as sinogram length (view number, or tangential bin 
> number, or displacement position). Am I right now?
> 

Conventionally the 'number of lines' in the sinogram is the number of
views. The 'number of columns' corresponds to what STIR calls tangential
position, and some other people call a radial coordinate.

> 
> In your mail:
> >From:"Kris Thielemans" <kris.thielemans at csc.mrc.ac.uk>
> >Reply-To: GATE feedback and helpline for Users 
> ><gate-users at lphe1pet1.epfl.ch>
> >To: "'Long ZHANG'" <zhanglong99 at tsinghua.org.cn>,
>   "'GATE feedback and helplinefor Users'" 
> <gate-users at lphe1pet1.epfl.ch>
> >Subject: RE: [gate-users] Image Reconstruction of Gate output
> >
> >> 
> >> BTW, I was pussled by the sinogram width of DST (420 crystal
> >> per ring). The number 249 is larger than the 420/2 = 210. How 
> >> can DST get the extra LORs of 39? By interpolation? Could 
> >> this help to improve the spatial resolution? Thank you!
> >> 
> >Notation: N= num_detectors per ring
> >
> >Why do you think that the max sinogram width is N /2? This is a 
> >hardware choice (recent CTI scanners tend to have 
> sinogram_width=N/2). 
> >The 'physical' maximum of LORs in 2D sinograms is (N^2-N)/2 
> (i.e. all 
> >lines between pairs of detectors, excluding the degenerate 
> cases, and 
> >identifying det pairs ij and ji). The max number of views is 
> N/2 (you'd 
> >expect N, but it's halved because of interleaving). So, the max 
> >sinogram width is something like (N-1)
> >
> >
> >Kris
> >
> >_______________________________________________
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> >gate-users at lphe1pet1.epfl.ch 
> >http://lphe1pet1.epfl.ch/mailman/listinfo/gate-users
> >
> 
> 
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