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--></style></head><body lang=ZH-CN link=blue vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black'>Dear Gate users,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black'>I’m trying to calculate LET and average LET(including dose-average and track-average) by Gate. But I met some problems.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black'><o:p> </o:p></span></p><p class=MsoNormal><b><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black'>First,</span></b><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black'> I found that in the user guide, it says that<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black'>“<i><span style='background:white'>DoseAveraged (default) or TrackAveraged LET both calculated by using the Geant4 EMCalculator method -GetElectronicStoppingPowerDEDX</span></i><span style='background:white'>”. But I checked the manual of Geant4(Application Developers Guide) and found that there is a “<i>ComputeElectronicDEDX method</i>” in G4EmCalculator class as shown below:<o:p></o:p></span></span></p><p class=MsoNormal><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif'><img width=512 height=456 style='width:5.3361in;height:4.7478in' id="图片_x0020_4" src="cid:image002.png@01D84296.F82372F0"></span><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif'><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif'>So I think maybe it use <i><span style='color:black;background:white'>ComputeElectronicDEDX method</span></i><span style='color:black;background:white'> ,not <i>GetElectronicStoppingPowerDEDX</i>. It maybe a little mistake in the manual of Gate in my opinion.<o:p></o:p></span></span></p><p class=MsoNormal><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black;background:white'><o:p> </o:p></span></p><p class=MsoNormal><b><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black;background:white'>Second, </span></b><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black;background:white'>if Gate use <i>ComputeElectronicDEDX method,</i> the LET is calculated by kinetic energy of particles as below:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black;background:white'>“<i>Instead of computing the LET as the quotient between the actual electronic energy loss and step length<o:p></o:p></i></span></p><p class=MsoNormal><i><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black;background:white'>computed during the simulation, we calculated the LET of the step, L<sub>sn</sub>, as the corresponding<o:p></o:p></span></i></p><p class=MsoNormal><i><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black;background:white'>mean energy loss per unit path length in the material according to the proton kinetic energy<o:p></o:p></span></i></p><p class=MsoNormal><i><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black;background:white'>at the step. In our code, L<sub>sn</sub> was obtained with the method ComputeElectronicDEDX() of<o:p></o:p></span></i></p><p class=MsoNormal><i><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black;background:white'>G4EmCalculator class.”<o:p></o:p></span></i></p><p class=MsoNormal><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black;background:white'>These are indicated in the </span><i><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:#333333'>Cortés-Giraldo M A and Carabe A 2015 <span style='border:none windowtext 1.0pt;padding:0cm'>Phys. Med. Biol.</span> <b><span style='border:none windowtext 1.0pt;padding:0cm'>60</span></b> 2645–69</span></i><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:#333333'>.But I wonder what method was used to calculate </span><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black;background:white'>DoseAveraged and TrackAveraged LET in Gate<i>.<o:p></o:p></i></span></p><p class=MsoNormal><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black;background:white'>And it’s very confusing to me. Because it also said in the Gate manual that if I use parallel computation, there will be <i>“2 output images for each LET actor and run, a file labeled as ‘-numerator’ and one labeled as ‘-denominator’. Building the quotient of these two images results in the averaged LET image. Note that the numerator and denominator images have to be summed up before the division.”</i>So why there are 2 outputs? And what are physical meanings of <i>denominator and numerator ?<o:p></o:p></i></span></p><p class=MsoNormal><i><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black;background:white'><o:p> </o:p></span></i></p><div><h2 style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:3.75pt;margin-left:0cm;line-height:22.5pt;background:#FCFCFE;word-break:break-all'><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black;background:white;font-weight:normal'>Hope to get the </span><span class=keyword><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:#434343;font-weight:normal'>interpretation of these confusing methods. Any suggestions and answers are welcomed and helpful to me. Thank you in advance!<o:p></o:p></span></span></h2><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif'>Best,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif'>Guangru Li<o:p></o:p></span></p></div><p class=MsoNormal><i><span lang=EN-US style='font-size:14.0pt;font-family:"Times New Roman",serif;color:black;background:white'><o:p> </o:p></span></i></p><p class=MsoNormal>从<span lang=EN-US> Windows </span>版<span lang=EN-US><a href="https://go.microsoft.com/fwlink/?LinkId=550986"><span lang=EN-US><span lang=EN-US>邮件</span></span></a></span>发送</p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'><o:p> </o:p></span></p></div></body></html>