[vtkusers] voxel's volume

[Mathieu Malaterre]

Laurent PAUL wrote:
> Hi users,
> 
> I'm wondering how voxels are mapped in my VolumeData.
> I've got an ImageData coming from Dicom. Voxel size is 0.74*0.74*2.7, I
> mean SizeX*SizeY*SizeZ(SizeZ=sliceThickness in dicom tag).
> But acquisiton had been made with a spacing between slices=1.3
> 
> So What is the voxel's volume?
> Since I'm working in 3D, I'm wondering how voxels are mapped when
> acquisition is overlapped.
> I think I should consider the "spacing between slices" when it is smaller
> than
> slice thickness. Am I right?

Laurent,

	This is definitely a question for DICOM people not viz people. Please 
reread the PS3.3 of the DICOM spec, you'll see that Slice Thickness is 
only the thickness of tissues where the signal is acquired. What you are 
looking for, really is Spacing Between Slices.

	As a side note using this tag is generally extremely dangerous, as you 
generally don't know if slices are joints, overlapping or disjoints. For 
a better implementation look at ITK-GDCM where we take two slices, the 
Image Orientation (Patient) and compute the zspacing from those.

HTH
Mathieu