Ulrich's questions

From: Lone Peak Engineering, Inc. (lpe@lonepeak.com)
Date: Thu Oct 24 1996 - 02:22:01 EEST


Ulrich had some questions concerning LPE's medical scan/.STL/RP activities
that I am finally getting to answer. I apologize that I did not resond
sooner, but I have been very busy, having just completed my 13th. business
trip in 10 months.

First - The question was: Is Lone Peak aware that MRI is not suited for
producing bone models?

I did not explain the research that we were doing fully, since I am never
sure how much detail everyone is interested. But, I think that the answer
here is fairly interesting. The bone models from MRI scan data that we
produced were dinsosaur bone models --- not human. The human wrist data
was CT data. The warning to never use MRI to produce a prosthesis is well
taken but not much of a worry in the case of a Utah Raptor or a T. Rex.

The other area that involved MR scan data conversion to .STL file and then
RP protoypes had to do with an evaluation of custom masks whereby the
individual would be scanned, a protoype tool produced and then the "soft"
portion of the mask produced.

Second: Have we assessed accuracy?

Isn't this a question that should be addressed as a whole by the
manufacturers of the scan equipment and RP equipment? Operator error and
machine maintenance issues come into play here.

Third: Ulrich is able to turn CT data into models overnight using CNC
milling of polyurethane foam (as compared, I guess to the way LPE does it
with RP equipment).

Okay, I tell my clients if you can get it machined then do so. Use the
technology that makes sense. If the client wants a machined foam prototype
then thats what they should have as long as it can be machined. On the
other hand, if they want a CT scan prototype that will allow them to
examine crack definition through the bone, then I would say get an SLA
prototype (even though we don't have an SLA). If they want a ceramic bone
for the R&D programs that are looking at implantable bioceramics then I
would say use our CerLAM approach or look at 3DP for ceramics along with
ACR's FDM, CamLEM, Rutgers FDM, Argonne's FDM and other programs (sorry if
I left anyone out).

If they prefer the feel of the ABS plastic for surgery simulations (cutting
with the knife) then FDM would be a good choice. Ditto with sterilizable
prototypes - use the systems that have the materials.

What I am saying here is that in the area of medical prototyping there is
room for a lot of choice and it will be the radiologist, the surgeon, and
the researchers that decide what protoype is best for them once they
understand the choices available. The fact that we can work directly with
their scan data - whatever the end purpose - using proprietary software --
and get the prototypes that they want - whatever the system -- that is
exciting!

Sorry for being long-winded. Must be jet lag.

Alair Griffin
Lone Peak Engineeing, Inc.
alair@lonepeak.com

Lone Peak Engineering, Inc.
12660 S. Fort St.
Draper, UT 84020
801-553-1732 TEL
801-553-1734 FAX
lpe@lonepeak.com
http://www.aros.net/~lonepeak/lpe



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