[gate-users] cylindricalPET

Tue Jul 19 19:13:13 CEST 2005

Sure, there's just one macro file. Thanks.

Yun

----- Original Message -----
From: Fernando Rannou <rannou at diinf.usach.cl>
Date: Tuesday, July 19, 2005 3:53 am
Subject: Re: [gate-users] cylindricalPET

> Would you please send all your macros in a tar file so
> I can run it myself.
> 
> Fernando
> 
> 
> On Mon, 2005-07-18 at 17:30 -0600, Yun Dong wrote:
> > Hi Fernando,
> > Thanks for your help. I have tried that the gamma ray go straight 
> into 
> > panels, and I also increase the activity to 100M Bq, but the 
> result 
> > seem be same till now. I am afraid that the problem would not be 
> from 
> > my setting but the GATE. Thanks.
> > 
> > Yun
> > 
> > ----- Original Message -----
> > From: Fernando Rannou <rannou at diinf.usach.cl>
> > Date: Monday, July 18, 2005 12:23 pm
> > Subject: Re: [gate-users] cylindricalPET
> > 
> > > Hi Yun,
> > > you could try to "focus" the backtobacks
> > > into the panels, that is modify
> > > 
> > > /gate/source/twogamma/gps/mintheta 0.deg 
> > > /gate/source/twogamma/gps/maxtheta 180.deg
> > > /gate/source/twogamma/gps/minphi 0. deg
> > > /gate/source/twogamma/gps/maxphi 360. deg
> > > 
> > > such that they always go in the direction of the detectors.
> > > I have the feeling that you just have a sensitivity problem,
> > > in the sense that the solid angle of your scanner is so small 
> that 
> > you
> > > need a lot, lot of events to get some coincidences. That would
> > > explain why you get some coincidences when you have more panels.
> > > So try to shoot the gammas straight into the detectors.
> > > 
> > > 
> > > Fernando
> > > 
> > > 
> > > On Mon, 2005-07-18 at 16:23 -0500, Yun Dong wrote:
> > > > Hi Fernando,
> > > > 
> > > > Thanks for your reply. I give my some configures of 
> simulation 
> > here:
> > > > 
> > > > Geometry: ~250mm*175mm dual-panel, distance between them is 50mm
> > > > # P H Y S I C S
> > > > /gate/physics/gamma/selectCompton standard
> > > > /gate/physics/gamma/selectPhotoelectric standard
> > > > /gate/physics/gamma/selectRayleigh lowenergy
> > > > /gate/physics/setElectronCut 300. cm
> > > > /gate/physics/setXRayCut 1. GeV
> > > > /gate/physics/setDeltaRayCut 1. GeV
> > > > # D I G I T I Z E R
> > > > /gate/digitizer/Singles/insert adder
> > > > /gate/digitizer/Singles/insert readout
> > > > /gate/digitizer/Singles/readout/setDepth 1
> > > > /gate/digitizer/Singles/insert blurring
> > > > /gate/digitizer/Singles/blurring/setResolution 0.15
> > > > /gate/digitizer/Singles/blurring/setEnergyOfReference 511. keV
> > > > /gate/digitizer/Singles/insert thresholder
> > > > /gate/digitizer/Singles/thresholder/setThreshold 250. keV
> > > > /gate/digitizer/Singles/insert upholder
> > > > /gate/digitizer/Singles/upholder/setUphold 750. keV
> > > > /gate/digitizer/Coincidences/setWindow 100. ns
> > > > # S O U R C E S
> > > > /gate/source/addSource twogamma
> > > > /gate/source/twogamma/setActivity 1000000. becquerel
> > > > /gate/source/twogamma/setType backtoback
> > > > /gate/source/twogamma/gps/particle gamma
> > > > /gate/source/twogamma/gps/energytype Mono
> > > > /gate/source/twogamma/gps/monoenergy 0.511 MeV
> > > > /gate/source/twogamma/gps/centre 0 0 0 mm
> > > > /gate/source/twogamma/gps/type Volume
> > > > /gate/source/twogamma/gps/shape Sphere
> > > > /gate/source/twogamma/gps/radius 0.5 mm
> > > > /gate/source/twogamma/gps/confine NULL
> > > > /gate/source/twogamma/gps/angtype iso
> > > > /gate/source/twogamma/gps/mintheta 0. deg
> > > > /gate/source/twogamma/gps/maxtheta 180. deg
> > > > /gate/source/twogamma/gps/minphi 0. deg
> > > > /gate/source/twogamma/gps/maxphi 360. deg
> > > > 
> > > > Just now I made some tests with resetting configure in 
> > > "benchmarkPET"> coming with GATE package: 
> > > > 1. (camera.mac 127L) /gate/head/ring/setRepeatNumber 4 (I 
> also 
> > > try 2)
> > > > 2. (benchmarkPET.mac 
> > > 45L)/gate/output/ascii/setOutFileCoincidencesFlag 1
> > > > (enable ascii coincindences output).
> > > > Then I find that when two heads, the size of coincindence 
> ascii 
> > > output> file is always zero after simulation start. But when 4 
> > > heads, the size
> > > > increases during the simulation. That's so confusing. 
> > > > 
> > > > Thank you again.
> > > > 
> > > > Best Regards
> > > > Yun
> > > > 
> > > > 
> > > > 
> > > > ----- Original Message -----
> > > > From: Fernando Rannou <rannou at diinf.usach.cl>
> > > > Date: Monday, July 18, 2005 11:28 am
> > > > Subject: Re: [gate-users] cylindricalPET
> > > > 
> > > > > Hi Yun
> > > > > you should get coincidences. Among the questions I would 
> ask are:
> > > > > 1) What kind of output are you using? I assume you set the 
> > > digitizer> > appropriately to collect coincidences.
> > > > > 2) how much activity, for how long?
> > > > > 3) are you simulating a positron emitter (of course)?
> > > > > 4) How big are the detectors with respect to the FOV?
> > > > > 
> > > > > Fernando
> > > > > 
> > > > > 
> > > > > 
> > > > > On Mon, 2005-07-18 at 12:10 -0500, Yun Dong wrote:
> > > > > > Hi everyone,
> > > > > > I am just simulating two parallel-panels PET system through
> > > > > > cylindricalPET system in GATE. Howver, I never get 
> > > coincidences, 
> > > > > just> GateSingles. Does it mean that cylindricalPET can 
> never 
> > > > > simulate the
> > > > > > open two parallel-detector PET system? Dose anybody have 
> > > some idesa?
> > > > > > Thank you so much.
> > > > > > 
> > > > > > Best Regards
> > > > > > Yun
> > > > > > _______________________________________________
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> > > > > 
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