There has been some discussion lately regarding "Real Time" (yuk!)
or slit scanning confocal microscopes.  We currently have the
Bio-Rad DVC-250 prototype as a demo. in our lab.
 
I have been using the autofluorescence from live human cheek cells
as a bench mark, to try and compare the sensitivity of various
confocals. The point scanning microscopes (Bio-Rad, Olympus, Leica,
and Molecular Dynamics) had no trouble producing nice images with
1% transmission ND filters, without any frame averaging.
 
Noran's slit scanner excited the cells with the AOD set to 70% (Nobody
could tell me what that means in terms of percentage laser transmitted),
With one frame the image quality was pretty poor, this is to be expected
since one frame is 1/30 of a second. Frame averaging for 10 seconds produced
a very nice image.
 
Using the Bio-Rad DVC-250 it was possible to just make out by eye the cells
structure.  When coupled to a SIT cammera quite good results were obtained
freezing a single video frame. Averaging 16 video frames produced very nice
images.  There is no software etc with the system, we connected our SIT
camera to our own imaging system. But there is no reason why the video output
cannot be connected to CoMOS or SOM software that are used with the Bio-Rad 600.
 
The optical sectioning does not seem to be as precise as the point scanners, but
that is to be expected.  Hopefully we shall be able to do some tests with some
fluorescent beads. I have noted some background stray light, possibly caused by
internal reflections, when scanning wide feilds. I should imagine this will be
fixed in the production model. So far I'm very impressed. Sorry I can't compare
it to the Meridian as we have not had the opertunity to examine one.
 
Regards,
                                        __    /
   Stephen H. Cody,                   _/  \__/ \
   Department of Physiology,         /          \
   University of Melbourne,         /  Australia \
   Parkville, Victoria 3052,        \   ____     /
   Australia.                        \_/    \_*_/
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