[vtkusers] Matching CT and RT dose coordinates

[Jothy]

FrameOfReferenceUIDs do match. I think the problem is with the different
readers used to read CT and RT dose.

I will use ImagePositionPatient to register the coordinates.

Thank you

Jothy

On Wed, Feb 23, 2011 at 6:04 PM, Scott Johnson <Scott.Johnson at neuwave.com>wrote:

>  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.
>
>
>
> 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.
>
>
>
> 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.
>
>
>
>                                 -- Scott
>
>
>
> *From:* vtkusers-bounces at vtk.org [mailto:vtkusers-bounces at vtk.org] *On
> Behalf Of *Jothy
>
> *Sent:* Wednesday, February 23, 2011 11:38 AM
> *To:* gdcm-developers; VTK Mailing List; itk;
> python-medphys at googlegroups.com
> *Subject:* [vtkusers] Matching CT and RT dose coordinates
>
>
>
> Hi all,
>
> 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.
>
> The image looks as in the attached figure.
>
> Any hint
>
> Thanks
>
> Jothy
>
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