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<p>Dear Gate Users,</p>
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<p>I'm simulating the mCT PET system with NEMA 2007 scatter fraction phantom. The results changing significantly with changing the QE in the digitizer, and I got the same results as the Published Experimental Data by putting the QE to 0.97. However, the randoms
are too high, and when I apply the same code for the sensitivity phantom with QE 0.9 I got the same results as the experimental, but for 0.97 I got different results. I was wondering where is the problem as I'm using GATE V7.2 ??</p>
<p>and what is the best physics code for the PET scanner?</p>
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<p>many thanks in advance</p>
<p>Amir <br>
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<p>P.S attached here the GATE code and the analysis<br>
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<div>###################################################</div>
<div>#### with the QE =0.97 #######</div>
<div>###################################################</div>
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<div>##### Reading from file: NECR1297.root</div>
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<div>##### the source activity (Mbq): 22</div>
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<div>##### nb of singles entries: 4929027</div>
<div> ### nb of Coincicences entries: 180052</div>
<div>...................</div>
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<div>Info in <TCanvas::Print>: GIF file GraphicFileName1.gif has been created</div>
<div> *********************************************************************************** </div>
<div> *********************************************************************************** </div>
<div> * _ _ _ _ * </div>
<div> * (_)_(_) S i m u l a t i o n A n a l y s i s (_)_(_) * </div>
<div> * (o o) (o o) * </div>
<div> * =\o/= by Amir Ghabrial =\o/= * </div>
<div> *********************************************************************************** </div>
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<div>##### Number of emitted particles : 43995161</div>
<div>##### Number of detected events : 4929027</div>
<div>##### ratio detected/emitted : 11.2036 %</div>
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<div> Acquisition start time = 0 [s]</div>
<div> Acquisition stop time = 2 [s]</div>
<div> F-18 decay factor = 0.999895</div>
<div> F-18 initial activity = 2.2e+07 [Bq]</div>
<div> F-18 decays = 4.39954e+07</div>
<div> ==> Expected total number of decays during the acquisition is 4.39954e+07 +/- 6632.9</div>
<div> There are 4.39954e+07 recorded decays</div>
<div> ==> there are 180052 coincidences (true, scattered, and random)</div>
<div> *********************************************************************************** </div>
<div> ==> absolute sensitivity = 0.209397 % </div>
<div> *********************************************************************************** </div>
<div> _______________________________________________________________ </div>
<div>| <span class="Apple-tab-span" style="white-space:pre">
</span> |</div>
<div>| ==> scatter fraction = 33.9998 % |</div>
<div>|______________________________________________________________|</div>
<div> </div>
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<div> ==> NECR = 47.1365 kcps</div>
<div> </div>
<div> *********************************************************************************** </div>
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<div> *********************************************************************************** </div>
<div># P R O M P T S = 180052 Cps</div>
<div># S C A T T E R S = 47458 Cps</div>
<div># T R U E S = 92125 Cps</div>
<div># R A N D O M S = 40469 Cps</div>
<div> *********************************************************************************** </div>
<div> _______________________________________________________________ </div>
<div>| <span class="Apple-tab-span" style="white-space:pre">
</span> |</div>
<div>| T O T A L S E N S I T I V I T Y : 1.04699 (kcps/Mbq)|</div>
<div>|______________________________________________________________|</div>
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<div> *********************************************************************************** </div>
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<div> *********************************************************************************** </div>
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<div>##### Number of emitted particles : 43995161</div>
<div>##### Number of detected events : 4929027</div>
<div>##### ratio detected/emitted : 11.2036 %</div>
<div>##### Primary events/detected events : 33.027 %</div>
<div> *********************************************************************************** </div>
<div>##### Scatter in the phantom : 16.0411 %</div>
<div>##### Scatter in the bed : 2.86612 %</div>
<div>##### Scatter in the crystal : 47.3715 %</div>
<div>##### Scatter in the backcompartment : 0.0390949 %</div>
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<div> *********************************************************************************** </div>
<div>##### Scatter order 1 : 62.7052 %</div>
<div>##### Scatter order 2 : 28.7689 %</div>
<div>##### Scatter order 3 : 7.09154 %</div>
<div>##### Scatter order 4 : 1.23322 %</div>
<div>##### Scatter order >4 : 0.201084 %</div>
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<div> *********************************************************************************** </div>
<div> *********************************************************************************** </div>
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<div>###################################################</div>
<div>#### with the QE =0.90 #######</div>
<div>###################################################</div>
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<div>##### Reading from file: NECR12.root</div>
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<div> please enter the source activity (bq): </div>
<div>22000000</div>
<div>##### the source activity (Mbq): 22</div>
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<div> please enter the StartTime(sec): </div>
<div>0</div>
<div> please enter the StopTime(sec): </div>
<div>2</div>
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<div>##### Reading from file: NECR12.root</div>
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<div>##### the source activity (Mbq): 22</div>
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<div>##### nb of singles entries: 3887218</div>
<div> ### nb of Coincicences entries: 113652</div>
<div>............</div>
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<div>Info in <TCanvas::Print>: GIF file GraphicFileName1.gif has been created</div>
<div> *********************************************************************************** </div>
<div> *********************************************************************************** </div>
<div> * _ _ _ _ * </div>
<div> * (_)_(_) S i m u l a t i o n A n a l y s i s (_)_(_) * </div>
<div> * (o o) (o o) * </div>
<div> * =\o/= by Amir Ghabrial =\o/= * </div>
<div> *********************************************************************************** </div>
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<div>##### Number of emitted particles : 44000672</div>
<div>##### Number of detected events : 3887218</div>
<div>##### ratio detected/emitted : 8.83445 %</div>
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<div> Acquisition start time = 0 [s]</div>
<div> Acquisition stop time = 2 [s]</div>
<div> F-18 decay factor = 0.999895</div>
<div> F-18 initial activity = 2.2e+07 [Bq]</div>
<div> F-18 decays = 4.39954e+07</div>
<div> ==> Expected total number of decays during the acquisition is 4.39954e+07 +/- 6632.9</div>
<div> There are 4.39954e+07 recorded decays</div>
<div> ==> there are 113652 coincidences (true, scattered, and random)</div>
<div> *********************************************************************************** </div>
<div> ==> absolute sensitivity = 0.158014 % </div>
<div> *********************************************************************************** </div>
<div> _______________________________________________________________ </div>
<div>| <span class="Apple-tab-span" style="white-space:pre">
</span> |</div>
<div>| ==> scatter fraction = 20.6404 % |</div>
<div>|______________________________________________________________|</div>
<div> </div>
<div> </div>
<div> ==> NECR = 42.5236 kcps</div>
<div> </div>
<div> *********************************************************************************** </div>
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<div> *********************************************************************************** </div>
<div># P R O M P T S = 113652 Cps</div>
<div># S C A T T E R S = 18081 Cps</div>
<div># T R U E S = 69519 Cps</div>
<div># R A N D O M S = 26052 Cps</div>
<div> *********************************************************************************** </div>
<div> _______________________________________________________________ </div>
<div>| <span class="Apple-tab-span" style="white-space:pre">
</span> |</div>
<div>| T O T A L S E N S I T I V I T Y : 0.789977 (kcps/Mbq)|</div>
<div>|______________________________________________________________|</div>
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<div> *********************************************************************************** </div>
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<div> *********************************************************************************** </div>
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<div>##### Number of emitted particles : 44000672</div>
<div>##### Number of detected events : 3887218</div>
<div>##### ratio detected/emitted : 8.83445 %</div>
<div>##### Primary events/detected events : 36.4297 %</div>
<div> *********************************************************************************** </div>
<div>##### Scatter in the phantom : 9.38772 %</div>
<div>##### Scatter in the bed : 1.65764 %</div>
<div>##### Scatter in the crystal : 52.1238 %</div>
<div>##### Scatter in the backcompartment : 0.0170816 %</div>
<div><br>
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<div> *********************************************************************************** </div>
<div>##### Scatter order 1 : 66.2682 %</div>
<div>##### Scatter order 2 : 26.7708 %</div>
<div>##### Scatter order 3 : 5.86739 %</div>
<div>##### Scatter order 4 : 0.949045 %</div>
<div>##### Scatter order >4 : 0.144631 %</div>
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<div> *********************************************************************************** </div>
<div> *********************************************************************************** </div>
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