Ultrafast laser scanner microscope.

Abstract

Advances in monolayer deposition of cervical cells have removed one of the last serious obstacles to the design of high-resolution automated diagnostic assessment systems. In this article, we describe the design considerations for a system that is capable of acquiring, within 60 sec, a 0.5 micron digitized image of a 4 cm2 area on a standard glass slide. The most feasible approach is found to be a system using a rotating polygon to sweep the focused spot from a laser across a 2-mm scan line while the slide is uniformly translated perpendicular to the scan direction the use of laser sources (a helium-neon laser at 632 nm and a krypton ion laser at 568 and/or 476 nm) as compared to the incoherent light sources used in conventional microscope systems alleviates many of the optical design problems and provides the proper wavelengths needed for recognition of Papanicolaou stained cells. We also find that focus control of the scanning spot should be achievable using a technique involving a holographic grating. Other relevant considerations such as sample heating problems, multiphoton absorption by the sample, detector signal-to-noise ratios, laser amplitude noise control, and the digitization and buffering of the data stream are also discussed.

Technologies supporting analytical cytology: clinical, research and drug discovery applications

“…Laser scanning cytometry has been developed over the last three decades by several groups and has subsequently been commercialized [66,67]. Laser scanning cytometry has been developed over the last three decades by several groups and has subsequently been commercialized [66,67].…”

SSAM: Solid-State Automated Microscope

“…The space taken by the electronic components can be reduced as described earlier. The [58]. Their system is essentially a widefield flying spot scanner that uses a laser source of illumination, a rotating polygonal mirror for x-direction scanning, and continuous mechanical stage motion for y-direction scanning.…”

Laser scanning phase modulation microscope

“…By contrast, in a scanning microscope, the specimen is illuminated point-by-point with a focused spot and the image is built up serially as the specimen is scanned in a raster format. Various scanning methods have been employed: scanning the spot across the specimen in two dimensions, using a cathode-ray rube (Young & Roberts, 1951;Montgomery et al, 1956), a Nipkow disk (Petran et al, 1968), a translating objective lens (Davidovits & Egger, 1971), or rotating mirrors (Freed & Engle, 1962;Hansen et al, 1981;Wilke, 1983;Carlsson et al, 1985); moving the specimen through a stationary spot on a scanning stage (Sheppard & Choudhury, 1977 Cremer, 1978;Brakenhoff et al, 1979;Wilson, 1980;Wijnaendts van Resandt et al, 1985), and scanning the beam in one direction while translating the specimen in the orthogonal direction (Shack et al, 1979;Bartels et al, 1981;Shoemaker et al, 1982). We also mention that slit rather than point scans have been used to good effect in certain applications (Koester, 1980).…”