<div dir="ltr"><span style="font-size: 11pt; color: rgb(0, 0, 0);">FrameOfReferenceUIDs do match. I think the problem is with the different readers used to read CT and RT dose.<br><br>I will use ImagePositionPatient to register the coordinates.<br>
<br>Thank you<br><br>Jothy<br></span><br><div class="gmail_quote">On Wed, Feb 23, 2011 at 6:04 PM, Scott Johnson <span dir="ltr"><<a href="mailto:Scott.Johnson@neuwave.com">Scott.Johnson@neuwave.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div link="blue" vlink="purple" lang="EN-US">
<div>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">If the FrameOfReferenceUIDs of the CT and the RT dose are the
same, they both exist in the same coordinate system, if they don’t, you
will have to register the dose to the CT somehow.</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Because the resolution of the dose will generally be different
than the CT a reasonable strategy is to loop through your CT voxels and use the
position at the center of that voxel to sample into the RT Dose grid.
When you sample into the RT Dose you may need to interpolate the actual dose
value. That dose value determines your shading.</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">The other issue to be aware of is that the dose grid may not
completely cover the CT image data. This is probably why the origins are
different for your data.</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> --
Scott</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span style="font-size:10.0pt">From:</span></b><span style="font-size:10.0pt">
<a href="mailto:vtkusers-bounces@vtk.org" target="_blank">vtkusers-bounces@vtk.org</a> [mailto:<a href="mailto:vtkusers-bounces@vtk.org" target="_blank">vtkusers-bounces@vtk.org</a>] <b>On Behalf Of </b>Jothy</span></p><div class="im">
<br>
<b>Sent:</b> Wednesday, February 23, 2011 11:38 AM<br>
<b>To:</b> gdcm-developers; VTK Mailing List; itk;
<a href="mailto:python-medphys@googlegroups.com" target="_blank">python-medphys@googlegroups.com</a><br>
</div><b>Subject:</b> [vtkusers] Matching CT and RT dose coordinates<p></p>
</div><div><div></div><div class="h5">
<p class="MsoNormal"> </p>
<div>
<p class="MsoNormal">Hi all,<br>
<br>
I am trying to overlay an dose shade on a CT slice.I am using vtkDICOMImageReader
to read the CT and vtkGDCMImageReader to display the dose shade.But I am having
problem with the coordinates.How to relate the coordinates? For e.g: I
get ImagePositionPatient of CT image for central slice as [-275,-524,-128.25]
and ImagePositionPatient for dose as [-228.65,-419.25,-122.5] adn their
spacings are [1.074,1.074,3] and [2.52.5.2.5] respectively for CT and Rt dose.<br>
<br>
The image looks as in the attached figure.<br>
<br>
Any hint<br>
<br>
Thanks<br>
<br>
Jothy</p>
</div>
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