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| 2. |
- 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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| 5. |
- Berg, Miguel, et al.
(författare)
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A Radio Resource Management Concept for "Bunched" Personal Communication Systems
- 1997
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Konferensbidrag (refereegranskat)abstract
- The radio resource management (RRM) techniques used in current 2nd generation mobile communication systems rely heavily on fixed frequency or timeslot allocation techniques which are not well suited for large variations in data rates. Spread spectrum systems proposed provide partial solutions to this problem but exhibit deficiencies when faced with uneven user populations. The overall objective of ACTS project AC090 FRAMES is to define, develop and evaluate a wideband multiple radio access scheme fulfilling the UMTS requirements. Within the project several RRM concepts have been proposed. The "bunch" concept discussed in this paper uses synchronous dynamic physical layer radio resource reservation combined with fast SIR based power control in a local cluster ("bunch"). Uncontrolled, "inter bunch", interference is handled by time/frequency hopping ("interference averaging"). In the paper some initial performance results are presented.
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| 7. |
- Berg, R, et al.
(författare)
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Time-gated viewing studies on tissuelike phantoms
- 1996
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Ingår i: Applied Optics. - 2155-3165. ; 35:19, s. 3432-3440
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Tidskriftsartikel (refereegranskat)abstract
- A time-gated technique to enhance viewing through highly scattering media such as tissue is discussed. Experiments have been performed on tissue like plastic phantoms to determine the possibilities and limitations of the technique. The effects of the time-gate width and the localization, size, and optical properties of hidden objects have been studied. A computer model to simulate light propagation in tissue is also presented. The predictions of the model are compared with experimental results. (C) 1996 Optical Society ofAmerica
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| 8. |
- Heyerdahl, H, et al.
(författare)
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Pharmacokinetic studies on 5-aminolevulinic acid-induced protoporphyrin IX accumulation in tumours and normal tissues
- 1997
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Ingår i: Cancer Letters. - 1872-7980. ; 112:2, s. 225-231
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Tidskriftsartikel (refereegranskat)abstract
- Laser-induced fluorescence (LIF) for in vivo point monitoring and fluorescence microscopy incorporating a CCD camera were used to study the fluorescence distribution of 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) in tumours. Fluorescence in a chemically induced adenocarcinoma in the liver of rats and in an aggressive basal cell carcinoma in a patient were studied after intravenous injection of ALA at a dose of 30 mg/kg body weight. The LIF technique demonstrated slightly more ALA-induced PpIX fluorescence in the tumour than in the surrounding normal liver and abdominal muscle of rats. The visible parts of the human basal cell carcinoma exhibited strong ALA-induced fluorescence, while this fluorescence was much weaker in the necrotic areas of the tumour and in the surrounding normal skin. (C) 1997 Elsevier Science ireland Ltd.
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| 9. |
- Jarlman, O, et al.
(författare)
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Laser transillumination of breast tissue phantoms using time-resolved techniques
- 1996
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Ingår i: European Radiology. - 0938-7994. ; 6:3, s. 387-392
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to evaluate a pulsed laser transillumination technique based on time-resolved detection on breast-tissue-like phantoms. Experiments have been performed on tissue-like plastic phantoms with different scattering characteristics. The effects of time-gate width, size, localisation and refractive index of hidden objects have been scrutinised. Our study showed that the shorter the time-gate the higher the contrast. The contrast is very dependent of the size of the hole, whereas the full width half maximum is not. Furthermore, the investigation showed that the changes of early detected light in an experimental setting is due to scattering, adn not to a higher speed of the transmitted light.
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| 10. |
- Jarlman, O, et al.
(författare)
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Time-resolved white light transillumination for optical imaging
- 1997
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Ingår i: Acta Radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 38:1, s. 185-189
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To describe a new breast-imaging method with the potential of multi-spectral optical transillumination based on a time-resolved technique. Material and Methods: A breast phantom was irradiated with ultra-short laser pulses of white light generated by self-phase modulation of an incident high-power laser pulse in water. Time-resolved detection of the transmitted light was performed. Contrast resolution was studied using different absorbers located inside the breast phantom. Results and Conclusion: The results showed that simultaneous, multi-spectral transillumination is possible. The technique can also be used for measurements of optical properties in tissue.
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