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Thanks for your comments Tom.  We are working on getting a demo of the
Swept Field Confocal in the near future.



On Thu, 14 Jul 2005 10:06:52 -0400, Tom Blanpied
<[log in to unmask]> wrote:


>Hi,
>
>I had the opportunity to check out the Swept Field in February at its
>development site at Prairie Technology, and was pretty impressed. The
>centerpiece as you say is the ability to select on the fly one of two
>slits or four pinhole sizes.  To do this, a motorized aperture plate is
>positioned such that the incoming laser (which is expanded in one
>dimension) is either passed through an excitation slit or passed into an
>array of microlenses which refocus onto a line of 32 pinholes.  The
>emission is cleverly descanned through a parallel set of pinholes or slits
>on the same motorized device.  I primarily worked in slit mode, as the
>microlenses in the unit I saw were being upgraded; they say the lenses are
>performing nicely now.  The pinhole-mode images even without the lenses
>were surprisingly nice, however; the lenses are only necessary  under
>laser-limited conditions, after all.  We used the cascasde 512b and imaged
>quantum dots or cultured neurons expressing GFP-tagged synaptic proteins.
>
>Since the sweep of the expanded laser line is driven by piezo, acquisition
>speeds are limited mostly by the frame rates of the camera.  For slit
>acqusition then, full frame illumination easily passes into the 100s of
>Hz, and a static line can be acquired at 3 kHz (or higher), compatible
>with many patch-clamp experiments.  Pinhole mode requires a short (1/32nd
>of the field) galvo movement.  It's not as though we can all buy a new
>camera whenever we want to go faster or at higher resolution, but it seems
>to me that this arrangement provides a huge range of capabilities and
>permits substantial flexibility for when detector technology advances.
>
>PSFs on the swept field in slit mode were of course slightly degraded
>compared to the spinning disk using a 100x 1.4 objective (as for the
>5Live), but this appears to me to be a good compromise for many live
>experiments.  Plus, the choice of two slits is another level of
>flexibility.  I suspect, but can't yet confirm, that optical sectioning in
>pinhole mode will be quite similar to that of the spinning disk. And
>again, the choice of pinholes should allow optimization of images at
>magnifications from 40x (or lower) to 100x. Interestingly, with the
>appropriate camera, disabling the piezo with the pinholes in place should
>allow multiple parallel lines to be scanned simultaneously at kHz rates
>and detected at Nyquist resolution with optimized pinholes over a range of
>objective magnifications.
>
>I'll be curious to hear from other folks who may have had a chance to test
>out this instrument.
>
>Tom
>-------------------------
>Thomas A. Blanpied, Ph.D.
>   Department of Physiology
>   University of Maryland, Baltimore
>   516 Howard Hall, 660 W. Redwood St.
>   Baltimore, MD 21201
>   [log in to unmask]
>   Tel (410) 706-4769
>   Fax (410) 706-8341