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Confocal purchase considerations. .
It does one no good if they have the best confocal machine made that
does not work at that level in their laboratory in the field. .
I think the critical point is reliability of the confocal. How often
does the machine break, go out of alignment, need repair etc. How good
the service department to repair the equipment. This is the key points
to ask in your geographical location--will it work to this great level
of performance in my laboratory?
If the image is the end point then all confocal microscopes essentially
work if laser light comes thought the objective. shocking No It is a
subjective call of what constitutes a functional machine. However, some
scientists actually ask for more out to the equipment than just taking a
pretty picture. The companies are advertising their equipment to do
fantastic things. Unfortunately they all do not work properly and can
not always achieve these fantastical things in the field.
The amount of published performance specifications the manufactures
have released to support their technology is None. NONE!!! Without
approved tests many of the machines may be working at suboptimal levels
and maybe yielding false and misleading data for the scientists that use
this equipment. . .
What is the reason that these tests are NOT released by the manufactures
Are they are afraid that scientists will actually test their equipment,
find problems with the equipment and increase the about of service
calls. Are there any other reasons why there are no performance tests
on confocal microscopes. Are the companies just saving money at the
expense of standard good equipment practices?
Personally, I would buy the machine that has the best service department
with the best service technician in your area and I would strongly
support any manufactures that releases specifications that their machine
can achieve. this is as important than the great hardware designed into
the Confocal .
Best Wishes
Bob
Robert M. Zucker, PhD
U.S. Environmental Protection Agency
Office of Research and Development
National Health and Environmental Effects Research Laboratory
Reproductive Toxicology Division, MD 72
Research Triangle Park, North Carolina, 27711
Tel: 919-541-1585; fax 919-541-4017
e-mail: [log in to unmask]
|---------+------------------------------->
| | "Alice L. Givan" |
| | <Alice.L.Givan@DARTM|
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| | Sent by: Confocal |
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| | 10/22/2004 09:17 AM |
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| Subject: Re: Comparison Shopping for Confocal |
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Search the CONFOCAL archive at
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Before purchasing a confocal microscope about a year ago, we tested two
systems during demos in our laboratory (and compared them with a third
system that we had in place). We used an informative tissue section and
also slides with beads. Among other tests, we tried to test
sensitivity and also looked at point spreads with a mirror slide and
with sub-resolution beads.
Even with this testing, our decision was not easy. For example, the
instrument that showed the tightest psfs produced the worst "looking"
images. And the instrument that showed the best sensitivity did not
have the other features that we required.
Arguably, the most important aspect of confocal imaging resides in the
objective. It was not possible to use the identical objective on all
three systems for our comparison -- and any system we purchased would,
in-the-end, be using a different objective. This made most comparisons
somewhat useless.
Also, because of different ways that system parameters are described by
different vendors, it was impossible to set all instruments up in the
same way for the comparison: for example, it was difficult to match
effective pinhole diameters or laser intensities.
One thing we (or the funding agencies) should be demanding: all the
vendors of these very expensive instruments should be providing
specifications (sensitivity; psf; x-y resolution; x-z resolution; etc.)
based on the same standards imaged under the same conditions. These
specifications would help in decisions about which instrument to
purchase and would also help in demanding service after purchase,
should instrument performance fall below the stated specs. Cars cost
about 5% of the cost of a confocal microscope --- yet we demand mpg
values and 0-60 times before we purchase a car.
Alice
Alice L. Givan
Englert Cell Analysis Laboratory
of the Norris Cotton Cancer Center
Dartmouth Medical School
Lebanon, NH 03756 USA
tel 603-650-7661
fax 603-650-6130
[log in to unmask]
www.dartmouth.edu/~celllab
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