[Gate-users] Re : SPECT intrinsic spatial resolution

Thu Sep 16 19:30:57 CEST 2010

Sorry about that - I mean a point source. Planar imaging I said to mean that the detector is not rotating or moving. The code for the source definition is as follows:

/gate/source/addSource SourceConfinement
/gate/source/SourceConfinement/gps/type Point
/gate/source/SourceConfinement/gps/centre 4. 0. 0. mm
/gate/source/SourceConfinement/gps/particle gamma
/gate/source/SourceConfinement/gps/energy 140. keV
/gate/source/SourceConfinement/setActivity 10.e-3 Ci
/gate/source/SourceConfinement/gps/angtype iso

-----Original Message-----
From: sebnem erturk [mailto:sebnem.erturk at gmail.com] 
Sent: Thursday, September 16, 2010 12:19 PM
To: Rajaram, Ramya (H USA)
Cc: gate-users at lists.opengatecollaboration.org
Subject: Re: [Gate-users] Re : SPECT intrinsic spatial resolution

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
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