<div dir="ltr"><div style="color:rgb(32,33,36);font-family:Roboto,RobotoDraft,Helvetica,Arial,sans-serif;font-size:medium;min-height:100%"><div style="width:1280px"><div style="float:left;display:flex;width:1280px"><div style="min-height:1px;float:left;overflow:hidden;width:1037px"><div id="m_627683070478141125gmail-:3" style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial;overflow-y:scroll;padding-right:0px;height:528px"><div id="m_627683070478141125gmail-:1" style="padding:0px;vertical-align:bottom;min-height:338px"><table cellpadding="0" style="border-spacing:0px;padding:0px;border-collapse:collapse;width:952px;display:block"><tbody></tbody></table><div style="min-height:100%"><div class="gmail-nH" style="width:1280px"><div class="gmail-nH" style=""><div class="gmail-nH gmail-bkL"><div class="gmail-no" style="float:left;display:flex;width:1280px"><div class="gmail-nH gmail-bkK gmail-nn" style="min-height:1px;float:left;overflow:hidden;width:1037px"><div class="gmail-nH"><div class="gmail-nH"><div class="gmail-nH gmail-ar4 gmail-z"><div class="gmail-aeI"><div class="gmail-AO" style=""><div id="gmail-:3" class="gmail-Tm gmail-aeJ" style="background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial;overflow-y:scroll;padding-right:0px;height:528px"><div id="gmail-:1" class="gmail-aeF" style="padding:0px;vertical-align:bottom;min-height:338px"><div class="gmail-nH"><div class="gmail-nH"><div class="gmail-nH gmail-g"><table class="gmail-Bs gmail-nH gmail-iY gmail-bAt" cellpadding="0" style="border-spacing:0px;padding:0px;border-collapse:collapse;width:952px;display:block"><tbody><tr><td class="gmail-Bu gmail-bAn" style="vertical-align:top;padding:0px;display:block;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><div class="gmail-nH gmail-if" style="margin:0px 16px 0px 0px;padding:0px"><div class="gmail-nH gmail-aHU" style=""><div class="gmail-nH gmail-hx" style="background-color:transparent;color:rgb(34,34,34);min-width:502px;padding:0px"><div class="gmail-nH"><div class="gmail-h7 gmail-ie gmail-nH gmail-oy8Mbf" tabindex="-1" style="clear:both;padding-bottom:0px;max-width:100000px;outline:none"><div class="gmail-Bk" style="margin-bottom:0px;border-width:0px;border-top-style:solid;border-right-style:initial;border-bottom-style:initial;border-left-style:initial;border-top-color:rgb(239,239,239);border-right-color:initial;border-left-color:initial;border-bottom-color:initial;border-radius:0px;width:936px;float:none"><div class="gmail-G3 gmail-G2" style="padding-top:0px;background-color:transparent;border-right:0px;border-bottom:0px rgba(100,121,143,0.12);border-left:0px;border-top:none;border-radius:0px;margin-bottom:0px;margin-left:0px;margin-right:0px"><div id="gmail-:16k"><div class="gmail-adn gmail-ads" style="border-left:none;padding:0px;display:flex"><div class="gmail-gs" style="margin:0px;padding:0px 0px 20px;width:864px"><div class="gmail-"><div id="gmail-:16n" class="gmail-ii gmail-gt" style="font-size:0.875rem;direction:ltr;margin:8px 0px 0px;padding:0px"><div id="gmail-:16m" class="gmail-a3s gmail-aXjCH" style="overflow:hidden;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:small;line-height:1.5;font-family:Arial,Helvetica,sans-serif"><div dir="ltr"><div style="margin:0px;padding:0px;border:0px;font-variant-numeric:inherit;font-variant-east-asian:inherit;font-stretch:inherit;line-height:inherit;font-family:Calibri,Arial,Helvetica,sans-serif;vertical-align:baseline;color:rgb(0,0,0)"><i><font size="1">As my previous email account expired, please reply to this one if you can. Thank you very much. </font></i></div><div style="margin:0px;padding:0px;border:0px;font-variant-numeric:inherit;font-variant-east-asian:inherit;font-stretch:inherit;font-size:12pt;line-height:inherit;font-family:Calibri,Arial,Helvetica,sans-serif;vertical-align:baseline;color:rgb(0,0,0)"><br></div><div style="margin:0px;padding:0px;border:0px;font-variant-numeric:inherit;font-variant-east-asian:inherit;font-stretch:inherit;font-size:12pt;line-height:inherit;font-family:Calibri,Arial,Helvetica,sans-serif;vertical-align:baseline;color:rgb(0,0,0)">Honored Gate experts and developers, </div><div style="margin:0px;padding:0px;border:0px;font-variant-numeric:inherit;font-variant-east-asian:inherit;font-stretch:inherit;font-size:12pt;line-height:inherit;font-family:Calibri,Arial,Helvetica,sans-serif;vertical-align:baseline;color:rgb(0,0,0)"><br></div><div style="margin:0px;padding:0px;border:0px;font-variant-numeric:inherit;font-variant-east-asian:inherit;font-stretch:inherit;font-size:12pt;line-height:inherit;font-family:Calibri,Arial,Helvetica,sans-serif;vertical-align:baseline;color:rgb(0,0,0)">I am experiencing some issues with deadtime in the PET detector when validating my simulated PET system in GATE against my real PET system. My PET system is similar to a typical standard ring PET system. I have built a corresponding GATE model to it as close as I can. But the count rate in the GATE model is twice higher than the physical system. I think it is due to the weird behavior of deadtime in digitizer settings. Then I did some simple validation simulations to prove that. In my real system, 11.3 mci (equivalent to 19 kBq/ml) is high enough to paralyze the system, i.e., the collected coincidence rate would increase then decrease as decays go by. However, in the GTE model, I have not observed such a trend yet. Here is a simple example: </div><div style="margin:0px;padding:0px;border:0px;font-variant-numeric:inherit;font-variant-east-asian:inherit;font-stretch:inherit;font-size:12pt;line-height:inherit;font-family:Calibri,Arial,Helvetica,sans-serif;vertical-align:baseline;color:rgb(0,0,0)"><br></div><div style="margin:0px;padding:0px;border:0px;font-variant-numeric:inherit;font-variant-east-asian:inherit;font-stretch:inherit;font-size:12pt;line-height:inherit;font-family:Calibri,Arial,Helvetica,sans-serif;vertical-align:baseline;color:rgb(0,0,0)"><div><img src="cid:ii_ka79i47b0" alt="Screenshot from 2020-05-14 13-43-13.png" width="472" height="80" class="gmail-CToWUd"><br></div><div>When I doubled the initial dose from 19 kBq/ml (11.3 mci) to 38 kBq/ml (22.6 mci), Gate also doubled the count of singles. To me, the deadtime module is not working. Because 19 kBq/ml is high enough to paralyze the detector, when the dose is doubled, it shall output ways less than twice of the singles. </div><div><br></div><div>Another simulation I did to show GATE mode reacts to deadtime is varying the deadtime: </div><div><br></div><div><div><img src="cid:ii_ka79p9h01" alt="Screenshot from 2020-05-14 14-10-41.png" width="472" height="66" class="gmail-CToWUd"><br></div></div><div>As you can see from the results above, the counts of singles barely change when deadtime increases from 10 ns to 100000 ns, which is very weird behavior to me. Also, 19 kBq/ml (11.3 mci) shall be high enough to paralyze the system. </div><div><br></div><div>Please provide any clue or any help to correct it. Thank you very much. </div><div>Sincerely,</div><div>Zhengzhi </div><div><br></div><div><span style="font-size:12pt"><br></span></div><div><span style="font-size:12pt"><br></span></div><div><span style="font-size:12pt">Following is my digitizer settings: </span><br></div><div>#=====================================================<br>#   D I G I T I Z E R: DETECTOR ELECTRONIC RESPONSE<br>#=====================================================<br>#      A D D E R<br>/gate/digitizer/Singles/insert                        adder<br><br>#       R E A D O U T<br>/gate/digitizer/Singles/insert                        readout<br>#/gate/digitizer/Singles/readout/setPolicy             TakeEnergyCentroid<br>#TakeEnergyWinner<br>/gate/digitizer/Singles/readout/setDepth              5<br><br>#      E N E R G Y   B L U R R I N G<br>/gate/digitizer/Singles/insert                        blurring<br>/gate/digitizer/Singles/blurring/setResolution        0.15<br>/gate/digitizer/Singles/blurring/setEnergyOfReference 511. keV<br><br>#       E N E R G Y   C U T<br>/gate/digitizer/Singles/insert                        thresholder<br>/gate/digitizer/Singles/thresholder/setThreshold      395. keV<br>/gate/digitizer/Singles/insert                        upholder<br>/gate/digitizer/Singles/upholder/setUphold            600. keV<br><br>/gate/digitizer/Singles/insert timeResolution<br>/gate/digitizer/Singles/timeResolution/setTimeResolution 0.700 ns<br><br>#       D E A D    T I M E<br>/gate/digitizer/Singles/insert deadtime<br>/gate/digitizer/Singles/deadtime/setDeadTime 1000. ns<br>/gate/digitizer/Singles/deadtime/setMode paralysable<br>/gate/digitizer/Singles/deadtime/chooseDTVolume Crystal<br><br><br>#=====================================================<br># C O I N C I D E N C E    S O R T E R<br>#=====================================================<br>/gate/digitizer/Coincidences/setWindow                5. ns<br>/gate/digitizer/Coincidences/minSectorDifference      1<br>/gate/digitizer/Coincidences/setOffset                0. ns<br>#/gate/digitizer/Coincidences/setMultiplePolicy        killAll<br>/gate/digitizer/Coincidences/describe<br><br>/gate/digitizer/name                                  delayedCoinc<br>/gate/digitizer/insert                                coincidenceSorter<br>/gate/digitizer/delayedCoinc/setOffset                90. ns<br>/gate/digitizer/delayedCoinc/setWindow                5. ns<br>/gate/digitizer/delayedCoinc/minSectorDifference      1<br>/gate/digitizer/delayedCoinc/describe<br><br>/gate/digitizer/name                                  finalCoinc<br>/gate/digitizer/insert                                coincidenceChain<br>/gate/digitizer/finalCoinc/addInputName               delayedCoinc<br>/gate/digitizer/finalCoinc/addInputName               Coincidences<br>/gate/digitizer/finalCoinc/usePriority                true<br>/gate/digitizer/finalCoinc/insert                     deadtime<br>/gate/digitizer/finalCoinc/deadtime/setDeadTime       10. ns<br>/gate/digitizer/finalCoinc/deadtime/setMode           paralysable<br>/gate/digitizer/finalCoinc/describe</div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></td><td class="gmail-Bu gmail-yM" style="vertical-align:top;padding:0px;width:0px;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><div class="gmail-nH" style="width:0px"><div class="gmail-dJ" style="height:0px;overflow:hidden;clear:both"></div></div></td><td class="gmail-Bu gmail-y3" style="vertical-align:top;padding:0px;width:0px;height:100px;background-image:initial;background-position:initial;background-size:initial;background-repeat:initial;background-origin:initial;background-clip:initial"><div class="gmail-Bt" style="height:0px;overflow:hidden;width:519px"></div><div class="gmail-nH gmail-bno gmail-adC" style="width:0px;margin:0px"><div class="gmail-nH"></div></div><div class="gmail-y4" style="height:2954.67px;width:0px;opacity:0"></div></td></tr></tbody></table></div></div></div></div></div></div></div></div></div></div></div><div class="gmail-nH gmail-nn" style="min-height:1px;float:left;width:0px;min-width:0px"><div class="gmail-no" style="float:left"></div><div class="gmail-dJ" style="height:0px;overflow:hidden;clear:both"></div></div><div class="gmail-nH gmail-bAw gmail-nn" style="min-height:1px;float:left;min-width:56px;width:56px;height:576px"><div class="gmail-brC-aT5-aOt-Jw" style="border-left:1px solid rgb(241,243,244);box-sizing:border-box;display:flex;height:576px;width:56px"><div class="gmail-brC-aT5-aOt-bsf-Jw" style="display:flex;margin-bottom:56px"><div class="gmail-brC-bsf-aT5-aOt" tabindex="0" style="height:100px;outline:none;overflow:hidden"><div id="gmail-gsc-gab-6" class="gmail-bse-bvF-I gmail-aT5-aOt-I gmail-bse-bvF-aLp" style="height:56px;outline:none;width:56px"><div class="gmail-aT5-aOt-I-JX-atM gmail-aT5-aOt-I-JX-atM-Kv" style="border-radius:50%;display:flex;height:40px;width:40px;border-color:rgb(232,240,254)"></div><div class="gmail-aT5-aOt-I-JX-atM gmail-aT5-aOt-I-JX-atM-J6" style="border-radius:50%;display:flex;height:40px;width:40px"></div><div class="gmail-aT5-aOt-I-JX-Jw" style="background-color:transparent;background-repeat:no-repeat;background-position:50% 50%;background-size:20px 20px;border-radius:50%;display:flex;height:40px;width:40px;background-image:url("https://www.gstatic.com/companion/icon_assets/calendar_2x.png")"></div></div><div id="gmail-gsc-gab-2" class="gmail-bse-bvF-I gmail-aT5-aOt-I gmail-bse-bvF-a9p" style="height:56px;outline:none;width:56px"><div class="gmail-aT5-aOt-I-JX-atM gmail-aT5-aOt-I-JX-atM-Kv" style="border-radius:50%;display:flex;height:40px;width:40px;border-color:rgb(254,247,224)"></div><div class="gmail-aT5-aOt-I-JX-atM gmail-aT5-aOt-I-JX-atM-J6" style="border-radius:50%;display:flex;height:40px;width:40px"></div><div class="gmail-aT5-aOt-I-JX-Jw" style="background-color:transparent;background-repeat:no-repeat;background-position:50% 50%;background-size:20px 20px;border-radius:50%;display:flex;height:40px;width:40px;background-image:url("https://www.gstatic.com/companion/icon_assets/keep_2x.png")"></div></div><div id="gmail-gsc-gab-4" class="gmail-bse-bvF-I gmail-aT5-aOt-I gmail-bse-bvF-aLp" style="height:56px;outline:none;width:56px"><div class="gmail-aT5-aOt-I-JX-atM gmail-aT5-aOt-I-JX-atM-Kv" style="border-radius:50%;display:flex;height:40px;width:40px;border-color:rgb(232,240,254)"></div><div class="gmail-aT5-aOt-I-JX-atM gmail-aT5-aOt-I-JX-atM-J6" style="border-radius:50%;display:flex;height:40px;width:40px"></div><div class="gmail-aT5-aOt-I-JX-Jw" style="background-color:transparent;background-repeat:no-repeat;background-position:50% 50%;background-size:20px 20px;border-radius:50%;display:flex;height:40px;width:40px;background-image:url("https://www.gstatic.com/companion/icon_assets/tasks2_2x.png")"></div></div><div class="gmail-brC-aT5-aOt-axR" id="gmail-:6g" style="border-top:1px solid rgb(218,220,224);margin:16px auto 0px;padding-bottom:16px;width:20px"></div><div class="gmail-bse-bvF-I gmail-aT5-aOt-I" id="gmail-qJTzr" style="height:56px;outline:none;width:56px"><div class="gmail-aT5-aOt-I-JX-atM gmail-aT5-aOt-I-JX-atM-Kv" style="border-radius:50%;display:flex;height:40px;width:40px;border-color:rgb(232,240,254)"></div><div class="gmail-aT5-aOt-I-JX-atM gmail-aT5-aOt-I-JX-atM-J6" style="border-radius:50%;display:flex;height:40px;width:40px"></div><div class="gmail-aT5-aOt-I-JX-Jw" style="background-color:transparent;background-repeat:no-repeat;background-position:50% 50%;background-size:20px 20px;border-radius:50%;displa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