[Gate-users] Re : SPECT intrinsic spatial resolution

[sebnem erturk]

what do you mean  by planar image of a point source?

what is the exact geometry of your source? (planar or point? )

cheers,

sebnem





On Thu, Sep 16, 2010 at 7:15 PM, Rajaram, Ramya (H USA) <
ramya.rajaram at siemens.com> wrote:

> I am simulating planar image of a point source, so there is no phantom.
> Also, I have put in only the collimator and the continuous crystal detector
> - no back compartment or any other layers. I output the projection images
> using the the following code:
>
> /gate/output/projection/enable
> /gate/output/projection/setFileName file6
> /gate/output/projection/pixelSizeX 2.4 mm
> /gate/output/projection/pixelSizeY 2.4 mm
> /gate/output/projection/pixelNumberX 256
> /gate/output/projection/pixelNumberY 256
>
> Thanks,
>
> Ramya
>
>
>
>
> -----Original Message-----
> From: Samuel BURG [mailto:samuel_burg at yahoo.fr]
> Sent: Thursday, September 16, 2010 10:35 AM
> To: Rajaram, Ramya (H USA); gate-users at lists.opengatecollaboration.org
> Subject: Re : [Gate-users] SPECT intrinsic spatial resolution
>
> Yes, GATE do apply a spatial blurring in your projection when using
> /gate/digitizer/Singles/spblurring/setSpresolution
>
> but to help you, we need your full macro file.
> also remember that the collimator, phantom scattering and the background
> compartment of the PMT play a lot in sp resolution.
>
>  -----------------------------------------------------------
> Samuel Burg
>
>
> Mail : <samuel_burg at yahoo.fr>
> -----------------------------------------------------------
> "Aw, come on, who would be so stupid as to insert a cast
> to make an error go away without actually fixing the error?"
> Apparently everyone.
> -- Raymond Chen --
> -----------------------------------------------------------
>
>
> ________________________________
>
> De : "Rajaram, Ramya (H USA)" <ramya.rajaram at siemens.com>
> À : gate-users at lists.opengatecollaboration.org
> Envoyé le : Jeu 16 septembre 2010, 16h 59min 48s
> Objet : [Gate-users] SPECT intrinsic spatial resolution
>
> Dear Gaters,
>
> Does GATE really convolve the intrinsic spatial resolution for SPECT? I
> have generated 256x256 projection images from two macros, both identical
> except for the fact that in one, the spResolution is set to 3.7 mm, in
> the other it is set to 0 mm and yet, the two images look identical. A
> simple profile also gives me the same system resolution for both - leads
> me to think the spResolution is somehow not being convolved -- could
> someone please explain/help?
>
> The following code is what I used to set the digitizer up:
>
> /gate/digitizer/Singles/insert adder
> /gate/digitizer/Singles/insert blurring
> /gate/digitizer/Singles/blurring/setResolution 0.09
> /gate/digitizer/Singles/blurring/setEnergyOfReference 140. keV
> /gate/digitizer/Singles/insert spblurring
> /gate/digitizer/Singles/spblurring/setSpresolution 0. mm (3.7 mm)
> /gate/digitizer/Singles/spblurring/verbose 2
> /gate/digitizer/Singles/insert thresholder
> /gate/digitizer/Singles/thresholder/setThreshold 50. keV
> /gate/digitizer/Singles/insert upholder
> /gate/digitizer/Singles/upholder/setUphold 200. keV
>
> Thank you very much,
>
> Ramya
>
>
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-- 
Sebnem Erturk
University of Pisa
Applied Physics Dpt.
Largo Pontecorvo
56127 Pisa-Italy
Office :0039 050 2214346
Mobile :0039 345 3331440
http://www.df.unipi.it/~fiig/