<html><head></head><body><div class="ydpd8e57438yahoo-style-wrap" style="font-family:times new roman, new york, times, serif;font-size:16px;"><div><div dir="ltr" data-setdir="false">Hi Gate-users,</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">I need a clarification regarding the example of positioning the activity image if it has different size and/or offset with the volume image, from the link below:</div><div dir="ltr" data-setdir="false"><a href="http://wiki.opengatecollaboration.org/index.php/Users_Guide:Voxelized_Source_and_Phantom#Voxelized_sources" rel="nofollow" target="_blank" class="">http://wiki.opengatecollaboration.org/index.php/Users_Guide:Voxelized_Source_and_Phantom#Voxelized_sources</a></div><div><br></div><div dir="ltr" data-setdir="false">Example:<br></div><div dir="ltr" data-setdir="false"><div><pre> #Activity image of 100 100 100 mm with an offset of 50 50 50 mm
#Phantom volume of 200 200 200 mm with an offset of 0 0 0 mm
#Phantom placement by GATE will be -100 -100 -100 mm
#The translation to apply is:
#translation = (50 50 50) + (0 0 0) + (-100 -100 -100) = (-50 -50 -50)
/gate/source/activityImage/setPosition -50 -50 -50 mm</pre></div><div dir="ltr" data-setdir="false">I want to know how the phantom placement by GATE is determined to obtain -100 -100 -100mm? Is it by (Phantom volume-Activity image) and the -ve sign is the direction? Or vice-versa?<br></div></div><div><br></div><div dir="ltr" data-setdir="false">Thank you.<br></div><div><br></div><div class="ydpd8e57438signature" dir="ltr" data-setdir="false"><div><font face="bookman old style, new york, times, serif" color="#00007f"></font> </div><div><font size="3"><em>Rukiah.<var id="ydpd8e57438yui-ie-cursor"></var></em></font></div><div style="margin: 5px 0px; padding: 0px; border-color: rgb(204, 204, 204); border-style: solid; border-width: 1px; min-height: 0px; line-height: 0; font-size: 0px;" class="ydpd8e57438hr"></div></div></div></div></body></html>