Confocal reflectance theta line scanning microscope for imaging human skin in vivo

ArticleinOptics Letters 31(7):942-4 · May 2006with12 Reads
DOI: 10.1364/OL.31.000942 · Source: PubMed
Abstract
A confocal reflectance theta line scanning microscope demonstrates imaging of nuclear and cellular detail in human epidermis in vivo. Experimentally measured line-spread functions determine the instrumental optical section thickness to be 1.7 +/- 0.1 microm and the lateral resolution to be 1.0 +/- 0.1 microm. Within human dermis (through full-thickness epidermis), the measured section thickness is 9.2 +/- 1.7 microm and the lateral resolution is 1.7 +/- 0.1 microm. An illumination line is scanned directly in the pupil of the objective lens, and the backscattered descanned light is detected with a linear array, such that the theta line scanner consists of only seven optical components.
    • "In addition, polarization-based pupil filtering techniques that use birefringence have been reported141516. Recently, the confocal system with D-shaped apertures also has been deeply studied and widely used due to its unique configuration17181920, in which the illumination and detection pupils do not overlap, so that the illumination and detection beams cross only in the focal region and the rejection of scattered light can be improved212223. In confocal systems, the key technique is to put a small pinhole in the focal plane to reduce the out-of-focus light [24]. "
    [Show abstract] [Hide abstract] ABSTRACT: Based on diffraction theory, this paper theoretically demonstrates improvements in axial resolution in confocal microscopy with fan-shaped apertures. It provides the optimal geometric parameters of the fan-shaped pupils to give the maximum axial resolution for a given pinhole size. To fully understand the overall performance, the signal-to-background ratio and the signal level with regard to the geometric parameters are discussed.
    Full-text · Article · Feb 2015
    • "The optical properties of skin tissues are highly variable between patients and at different locations within an individual. Our goal has been to develop a phantom with reproducible optical properties that lie within the range of values observed by us and others in human samples [18,19]. As mentioned previously, measurements in Intralipid (Figs. 1d, 1e) reveal that this homogeneous phantom does not recapitulate the heterogeneities in real tissues that cause beam steering and aberrations (Figs. "
    [Show abstract] [Hide abstract] ABSTRACT: Phantoms play an important role in the development, standardization, and calibration of biomedical imaging devices in laboratory and clinical settings, serving as standards to assess the performance of such devices. Here we present the design of a liquid optical phantom to facilitate the assessment of optical-sectioning microscopes that are being developed to enable point-of-care pathology. This phantom, composed of silica microbeads in an Intralipid base, is specifically designed to characterize a reflectance-based dual-axis confocal (DAC) microscope for skin imaging. The phantom mimics the scattering properties of normal human epithelial tissue in terms of an effective scattering coefficient and a depth-dependent degradation in spatial resolution due to beam steering caused by tissue micro-architectural heterogeneities.
    Full-text · Article · Dec 2012
    • "The results to date indicate that the divided-pupil approach may offer improved imaging performance in scattering tissues, compared to the full-pupil, with either point-scanning or line-scanning. Moreover, as part of ongoing efforts to translate confocal microscopy for detection of skin cancer, we are exploring a simpler and lower-cost line-scanning configuration789 that may offer a practical alternative to currently available point-scanning technology. Thus, to determine the best possible approach for clinical applications, we are now developing a quantitative understanding of imaging performance for a set of scanning and pupil conditions. "
    [Show abstract] [Hide abstract] ABSTRACT: Both point-scanning and line-scanning confocal microscopes provide resolution and optical sectioning to observe nuclear and cellular detail in human tissues, and are being translated for clinical applications. While traditional point-scanning is truly confocal and offers the best possible optical sectioning and resolution, line-scanning is partially confocal but may offer a relatively simpler and lower-cost alternative for more widespread dissemination into clinical settings. The loss of sectioning and loss of contrast due to scattering in tissue is more rapid and more severe with a line-scan than with a point-scan. However, the sectioning and contrast may be recovered with the use of a divided-pupil. Thus, as part of our efforts to translate confocal microscopy for detection of skin cancer, and to determine the best possible approach for clinical applications, we are now developing a quantitative understanding of imaging performance for a set of scanning and pupil conditions. We report a Fourier-analysis-based computational model of confocal microscopy for six configurations. The six configurations are point-scanning and line-scanning, with full-pupil, half-pupil and divided-pupils. The performance, in terms of on-axis irradiance (signal), resolution and sectioning capabilities, is quantified and compared among these six configurations.
    Full-text · Article · Aug 2011
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