<html><head></head><body><div style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"><div><span style="font-size:10.0pt;line-height:115%;font-family:"Courier New";mso-fareast-font-family:"Times New Roman";color:black;mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language:AR-SA">Hi GATE users</span><br></div><div><span style="font-size:10.0pt;line-height:115%;font-family:"Courier New";mso-fareast-font-family:"Times New Roman";color:black;mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language:AR-SA"><div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size:10.0pt;font-family:"Courier New";mso-fareast-font-family:"Times New Roman";color:black">I have modeled a trapezoid as the collimator in my SPECT
simulation.</span><span style="font-size: 10pt;">Everything seems to be right, but, I have faced an unexpected
problem: an</span><span style="font-size: 10pt;"> extra volume exists
inside the trapezoid (as shown in attached figure).</span></div><div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size: 10pt;"><span style="font-size:10.0pt;line-height:115%;font-family:"Courier New";mso-fareast-font-family:"Times New Roman";color:black;mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language:AR-SA">Here
are the commands used to define aforementioned trapezoid:</span><br></span></div><div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size: 10pt;"><span style="font-size:10.0pt;line-height:115%;font-family:"Courier New";mso-fareast-font-family:"Times New Roman";color:black;mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language:AR-SA"><p class="ydp1c51f52cMsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size:10.0pt;font-family:"Courier New";mso-fareast-font-family:"Times New Roman";color:black"># Collimator (Trapezoidal Collimator)</span></p>

<div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size:10.0pt;font-family:"Courier New";mso-fareast-font-family:"Times New Roman";color:black">/gate/world/daughters/name collimator</span></div><div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size: 10pt;">/gate/world/daughters/insert trpd</span></div><div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size: 10pt;">/gate/collimator/geometry/setX1Length 0.7 cm</span></div><div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size: 10pt;">/gate/collimator/geometry/setY1Length 0.7 cm</span></div>

<div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size:10.0pt;font-family:"Courier New";mso-fareast-font-family:"Times New Roman";color:black">/gate/collimator/geometry/setX2Length 9 cm</span></div><div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size: 10pt;">/gate/collimator/geometry/setY2Length 5 cm</span></div>

<div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size:10.0pt;font-family:"Courier New";mso-fareast-font-family:"Times New Roman";color:black">/gate/collimator/geometry/setZLength 5 cm</span></div><div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size:10.0pt;font-family:"Courier New";mso-fareast-font-family:"Times New Roman";color:black"><br></span></div><div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size: 10pt;">/gate/collimator/setMaterial Lead</span></div><div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size: 10pt;">/gate/collimator/vis/setColor red</span></div><div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size: 10pt;">/gate/collimator/vis/forceWireframe</span></div><div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size: 10pt;"><br></span></div><div style="margin-bottom:0in;margin-bottom:.0001pt;line-height:normal;tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-size: 10pt;"> Any suggestion or idea
would be appreciated; thank you in advance.</span></div></span></span></div></span></div></div></body></html>