| 41. |
- Andersson-Engels, Stefan, et al.
(författare)
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Medical Diagnostic System Based On Simultaneous Multispectral Fluorescence Imaging
- 1994
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Ingår i: Applied Optics. - 2155-3165. ; 33:34, s. 8022-8029
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Tidskriftsartikel (refereegranskat)abstract
- A multicolor fluorescence imaging system applied to medical diagnostics is described. The system presented simultaneously records four fluorescence images in different wavelength bands, permitting low-resolution spectroscopy imaging. An arithmetic function image of the four spectral images is constructed by a pixel-to-pixel calculation and is presented on a monitor in false-color coding. A sensitive detector is required for minimizing the excitation energy necessary to obtain an image and thus avoid side effects on the investigated tissue. Characteristics of the system of importance for the detector sensitivity as well as image quality are discussed. A high degree of suppression of ambient background light is reached with this system by the use of a pulsed laser as an excitation source together with gated detection. Examples of fluorescence images from tumors on the hind legs and in the brain of rats injected with Photofrin are given.
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| 42. |
- Andersson-Engels, Stefan, et al.
(författare)
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Multi-colour fluorescence imaging in connection with photodynamic therapy of delta-amino levulinic acid (ALA) sensitised skin malignancies
- 1995
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Ingår i: Bioimaging. - 0966-9051. ; 3:3, s. 134-143
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Tidskriftsartikel (refereegranskat)abstract
- Abstract A system for multi-colour fluorescence imaging of tissue is described. The instrument is mainly developed for tissue diagnostics to identify and localise malignant tumours, but might also be useful for real-time monitoring of the therapeutic dose delivered during photodynamic therapy. In vivo examples from various malignant skin lesions following topical δ-amino levulinic acid (ALA) administration are presented. The diagnostic system utilises both characteristics of a fluorescent tumour marker, such as a porphyrin containing substance, and the native tissue autofluorescence to characterise the tissue. A dimensionless function of three or four simultaneously recorded fluorescence intensities is formed and an optimum-contrast image is calculated pixel-by-pixel.
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| 43. |
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| 44. |
- Andersson-Engels, Stefan, et al.
(författare)
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Multispectral Tissue Characterization With Time-resolved Detection of Diffusely Scattered White-light
- 1993
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Ingår i: Optics Letters. - 0146-9592. ; 18:20, s. 1697-1699
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Tidskriftsartikel (refereegranskat)abstract
- A novel technique for the noninvasive measurement of tissue optical properties simultaneously at all visible and near-infrared wavelengths is presented. The technique is based on.the time-resolved detection of multicolor diffusely scattered light. Short pulses of white light are/produced by using self-phase modulation by focusing the light from a short-pulsed high-power laser into a cuvette filled with water. After spectral dispersion in a polychromator and temporal dispersion in a streak tube, a two-dimensional CCD camera was used as a detector, with one dimension used for time resolution and the other one for wavelength separation.
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| 45. |
- Andersson-Engels, Stefan, et al.
(författare)
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Preliminary evaluation of two fluorescence imaging methods for the detection and the delineation of basal cell carcinomas of the skin
- 2000
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Ingår i: Lasers in Surgery and Medicine. - 0196-8092. ; 26:1, s. 76-82
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Background and ObjectiveFluorescence techniques can provide powerful noninvasive means for medical diagnosis, based on the detection of either endogenous or exogenous fluorophores. The fluorescence of δ-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) has already shown promise for the diagnosis of tumors. The aim of the study was to investigate the localization of skin tumors after the topical application of ALA, by detecting the PpIX fluorescence either in the spectral or in the time domain.Study Design/Materials and MethodsTwo fluorescence imaging systems were used to identify basal cell carcinomas of the skin in humans, after topical application of 20% ALA ointment. Both systems rely on the comparison between the exogenous and the endogenous fluorescence, performed either in the spectral domain or in the time domain. The first system works by using three images acquired through different spectral filters, whereas the second one measures the spatial map of the average fluorescence lifetime of the sample.ResultsA clear demarcation of skin malignancies was successfully performed in vivo noninvasively with both fluorescence imaging systems.ConclusionThe two complementary approaches considered in the present study show promise for skin tumor detection and delineation based on specific fluorescence features. Lasers Surg. Med. 26:76–82, 2000. © 2000 Wiley-Liss, Inc.
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