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<DIV><FONT face=Verdana size=2>Hi, Patrick,</FONT></DIV>
<DIV><FONT face=Verdana size=2></FONT> </DIV>
<DIV><FONT face=Verdana size=2>Thank you for your help on the object disappering
during tracking. I will try the code later.</FONT></DIV>
<DIV><FONT face=Verdana size=2></FONT> </DIV>
<DIV>Today I found another problem, here is a head phantom scanned with CT
gantry tilt.</DIV>
<DIV>The angle is</DIV>
<DIV>(0018|1120) Gantry/Detector Tilt = 6.68</DIV>
<DIV> </DIV>
<DIV>so IGSTK will not read this set of DICOM.</DIV>
<DIV> </DIV>
<DIV>I see there is several DICOM sets with gantry tilt in
Sandbox\Testing\Data\CT_WITH_GANTRYTILT,</DIV>
<DIV>E000147_1, E000147_2, E000147_4 can be read by NeedleBiopsy app, whose
angle is</DIV>
<DIV>-16.5, -6.5, -1.5 separately.</DIV>
<DIV>But E000147_3, E000147_5, E000147_6 can not be read, whose angle is</DIV>
<DIV>6.5, 10.5, 20.5 separately.</DIV>
<DIV> </DIV>
<DIV>I do not know why the gantry tilt with positive angle can not be read,
while the one with negative</DIV>
<DIV>angle can be read into IGSTK. It seems that the shear transform should be
corrected in either positive</DIV>
<DIV>angle or negative angle. Is that a bug in
igstkDICOMImageReader.txx around line 593-607 ?</DIV>
<DIV> </DIV>
<DIV> // Check if the gantry tilt is within an acceptable
range<BR> double gantryTilt;<BR> double
gantryTiltThreshold=0.01;<BR> <BR> std::stringstream
sstr;<BR> sstr.str( m_GantryTilt );<BR> sstr
>> gantryTilt;</DIV>
<DIV> </DIV>
<DIV> if( gantryTilt > gantryTiltThreshold
)<BR> {<BR>
this->m_ImageReadingErrorInformation = "Unacceptable gantry
tilt";<BR> this->m_StateMachine.PushInput(
this->m_ImageReadingErrorInput );<BR>
this->m_StateMachine.ProcessInputs();<BR>
return; <BR> }</DIV>
<DIV> </DIV>
<DIV>And due to affine transform is needed to correct gantry tilt, should the
gantry tilted CT images</DIV>
<DIV>be read or not be read into IGSTK before correction?</DIV>
<DIV> </DIV>
<DIV>Thank you very much!</DIV>
<DIV> </DIV>
<DIV>Fucang</DIV>
<DIV> </DIV>
<DIV> </DIV></BODY></HTML>