Re: [photo-3d] Re: 3D X-ray CT

["John A. Rupkalvis" <stereoscope@xxxxxxxxxxxxx>]

Subject: [photo-3d] Re: 3D X-ray CT


> Abram Klooswyk wrote: "The computers have software to generate so-called
3D
> images
> from a consecutive series of such slices, but these 3D images
> are of the type you see everywhere as result of so-called 3D
> rendering CAD programs..."

Some of these programs were designed before CT scans, but can be readily
applied to same.  These were the so-called "laminar construction" CAD and
CAE programs, which were written for the purpose of showing perspective
views of mechanism assemblies constructed from laminated parts, such as
padlocks.  Although not necessarily stereoscopic as displayed, the z-axis
information made this a relatively easy interpolation.

As applied to CT scans, the z-axis resolution would certainly be determined
(as you pointed out) by the spacing between the scans.  10mm (with the
interstitial information morphed in) would probably be adequate for some
applications, such as dislocations.  For microsurgery pre-op views or the
detection of very small tumors, they would probably take more views
(narrower spacing between slices) anyway.

In any case, stereoscopic renderings derived from the CT information could
be useful.  In some cases, such as minimizing the invasive volume of a
surgical incision, the surgeon's viewing of the slices stereoscopically
rather than flat could give the surgeon a much better concept of the
particular optimum depth and area of a particular incision.  Analyzing CT
slices flat, and mentally reconstructing these can be imprecise even for an
experienced CT reader or surgeon.   Although the procedures are pretty much
standardized, the actual size of a cut is determined individually by the
surgeon in each case depending upon the anatomical bulk of the tissue
necessary to cut through to reach the intended location on a particular
patient.  This could be much more accurately determined from stereoscopic
pre-op analysis.

JR


 

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