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Träfflista för sökning "WFRF:(Svanberg Sune) srt2:(1995-1999)"

Sökning: WFRF:(Svanberg Sune) > (1995-1999)

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1.
  • af Klinteberg, C, et al. (författare)
  • Laser-induced fluorescence diagnostics of basal cell carcinomas of the skin following topical ALA application
  • 1996
  • Ingår i: Optical Biopsies and Microscopic Techniques, Proceedings of. - : SPIE. - 0819423289 ; 2926, s. 32-40
  • Konferensbidrag (refereegranskat)abstract
    • Fourteen patients with superficial basal cell carcinomas (BCCs) and fifteen patients with nodular BCCs were investigated by means of laser-induced fluorescence (LIF) in connection with photodynamic therapy (PDT). Topical application of delta-amino levulinic acid (ALA) was performed six hours prior to the treatment session. Fluorescence spectra were recorded, using a point-monitoring system with an excitation wavelength of 405 nm. The measurements were performed in scans over the lesion and the surrounding normal skin before application of ALA, and immediately before and after the laser treatment. The selective uptake of the photosensitiser resulted in a fluorescence intensity ratio of 2.4:1 for superficial BCCs and 2.5:1 for nodular BCCs. If the fluorescence intensity was divided by the autofluorescence, this resulted in a contrast enhancement of about a factor 6 for tumour tissue. In seven patients (five with nodular BCC and two with superficial BCC), additional fluorescence measurements were performed two and four hours following the ALA application, and two hours after the PDT procedure. Thus, the kinetics of the transformation of ACA to protoporphyrin IX (PpIX) could be followed, which indicated that the synthesis of PpIX was more rapid in the tumour than in the normal tissue. After four hours, the PpIX level inside the tumour was saturated, while there still was an accumulation in the surrounding skin. The highest contrast between tumour and normal skin was reached within two hours after the ALA application.
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2.
  • Eker, C, et al. (författare)
  • Clinical spectral characterisation of colonic mucosal lesions using autofluorescence and delta aminolevulinic acid sensitisation
  • 1999
  • Ingår i: Gut. - : BMJ. - 1468-3288 .- 0017-5749. ; 44:4, s. 511-518
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and aims-Laser induced fluorescence (LIF) from colonic mucosa was measured in vivo with and without delta aminolevulinic acid (ALA) in an attempt to differentiate between neoplasia and non-neoplasia in real time during colonoscopy. Methods-Spectra from 32 adenomas, 68 normal sites, and 14 hyperplastic polyps in 41 patients were obtained with a point monitoring system. Twenty one of the patients had been given a low dose of ALA as a photosensitiser before the examination. Light of 337, 405, or 436 nm wavelength was used as excitation. Stepwise multivariate Linear regression analysis was performed. Results-With 337 nm excitation, 100% sensitivity and 96% specificity was obtained between normal mucosa and adenomas. Seventy seven per cent of the hyperplastic polyps were classified as non-neoplastic. When exciting with 405 and 436 nm, the possibility of distinguishing different types of tissue was considerably better in the ALA patients than in the non-ALA patients. Conclusions-The in vivo point measurements imply that a good discrimination between normal tissue and adenomatous polyps can be obtained using the LIF technique. Excitation at 337 nm and at 405 nm or 436 nm using ALA gives good results. LIF also shows potential for distinguishing adenomatous from hyperplastic polyps. The number of detection wavelengths could be reduced if chosen properly.
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4.
  • Svanberg, Katarina, et al. (författare)
  • Clinical multi-colour fluorescence imaging of malignant tumours - Initial experience
  • 1998
  • Ingår i: Acta Radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 39:1, s. 2-9
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: The detection of malignant tumours relies on a variety of diagnostic procedures including X-ray images and, for hollow organs, endoscopy. The purpose of this study was to present a new technique for non-invasive tumour detection based on tissue fluorescence imaging. Material and Methods: A clinically adapted multi-colour fluorescence system was employed in the real-time imaging of malignant rumours of the skin, breast, head and neck region, and urinary bladder. Tumour detection was based on the contrast displayed in fluorescence between normal and malignant tissue, related to the selective uptake of tumour-marking agents, such as haematoporphyrin derivative (HPD) and Famine levulinic acid (ALA), and natural chromophore differences between various tissues. In order to demarcate basal cell carcinomas of the skin, ALA was applied topically 4-6 h before the fluorescence investigation. For urinary bladder tumour visualisation (transitional cell carcinoma of different stages including carcinoma in situ), ALA was instilled into the bladder 1-2 h prior to the study. Malignant and premalignant lesions in the head and neck region were imaged after i.v. injection of HPD (Photofrin). Finally, the extent of in situ and invasive carcinomas of the breast was investigated in surgically excised specimens from patients that received a low-dose injection of HPD 24 h prior to the study. The tumour imaging system was coupled to an endoscope. Fluorescence light emission from the tissue surface was induced with 100-ns-long optical pulses at 390 nm, generated from a frequency-doubled alexandrite laser. With the use of special image-splitting optics, the tumour fluorescence, intensified in a micro-channel plate, was imaged in 3 selected wavelength bands. These 3 images were processed together to form a new optimised-contrast image of the tumour. This image, updated at a rate of about 3 frames/s, was mixed with a normal colour video image of the tissue. Results: A clear demarcation from normal surrounding tissue was found during in vivo measurements of superficial bladder carcinoma, basal cell carcinoma of the skin, and leukoplakia with dysplasia of the lip, and in in vitro investigations of resected breast cancer. Conclusions: The initial clinical experience of using multi-colour fluorescence imaging has shown that the technique has the potential to reveal malignant tumour tissue, including non-invasive early carcinoma and also precancerous tissue. Further investigations are needed to fully develop the method.
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5.
  • af Klinteberg, C, et al. (författare)
  • Kinetic fluorescence studies of 5-aminolaevulinic acid-induced protoporphyrin IX accumulation in basal cell carcinomas
  • 1999
  • Ingår i: Journal of Photochemistry and Photobiology, B: Biology. - 1011-1344. ; 49:2-3, s. 120-128
  • Tidskriftsartikel (refereegranskat)abstract
    • Laser-induced fluorescence (LIF) investigations have been performed in connection with photodynamic therapy (PDT) of basal cell carcinomas and adjacent normal skin following topical application of 5-aminolaevulinic acid (ALA) in order to study the kinetics of the protoporphyrin TX (PpIX) build-up. Five superficial and 10 nodular lesions in 15 patients are included in the study. Fluorescence measurements are performed prior to the application of ALA, 2, 4 and 6 h port ALA application, immediately post PDT (60 J cm(-2) at 635 nm), and 2 h after the treatment. Hence, the build-up, photobleaching and re-accumulation of PpIX can be followed. Superficial lesions show a maximum PpIX fluorescence 6 h post ALA application, whereas the intensity is already the highest 2-4 h after the application in nodular lesions. Immediately post PDT, the fluorescence contribution at 670 Mm from the photoproducts is about 2% of the pre-PDT PpIX fluorescence at 635 nm. Two hours after the treatment, a uniform distribution of PpIX is found in the lesion and surrounding normal tissue. During the whole procedure, the autofluorescence of the lesions and the normal skin does not vary significantly from the values recorded before the application of ALA. (C) 1999 Elsevier Science S.A. All rights reserved.
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6.
  • Andersson-Engels, Stefan, et al. (författare)
  • In vivo fluorescence imaging for tissue diagnostics
  • 1997
  • Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 42:5, s. 815-824
  • Tidskriftsartikel (refereegranskat)abstract
    • Non-invasive fluorescence imaging has the potential to provide in vivo diagnostic information for many clinical specialities. Techniques have been developed over the years for simple ocular observations following UV excitation to sophisticated spectroscopic imaging using advanced equipment. Much of the impetus for research on fluorescence imaging for tissue diagnostics has come from parallel developments in photodynamic therapy of malignant lesions with fluorescent photosensitizers. However, the fluorescence of endogenous molecules (tissue autofluorescence) also plays an important role in most applications. In this paper, the possibilities of imaging tissues using fluorescence spectroscopy as a mean of tissue characterization are discussed. The various imaging techniques for extracting diagnostic information suggested in the literature are reviewed. The development of exogenous fluorophores for this purpose is also presented. Finally, the present status of clinical evaluation and future directions are discussed.
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7.
  • Andersson-Engels, Stefan, et al. (författare)
  • Multi-colour fluorescence imaging in connection with photodynamic therapy of delta-amino levulinic acid (ALA) sensitised skin malignancies
  • 1995
  • Ingår i: Bioimaging. - 0966-9051. ; 3:3, s. 134-143
  • 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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9.
  • Heyerdahl, H, et al. (författare)
  • Pharmacokinetic studies on 5-aminolevulinic acid-induced protoporphyrin IX accumulation in tumours and normal tissues
  • 1997
  • Ingår i: Cancer Letters. - 1872-7980. ; 112:2, s. 225-231
  • 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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10.
  • Johansson, Jonas, et al. (författare)
  • Laser-induced fluorescence studies of normal and malignant tumour tissue of rat following intravenous injection of delta-amino levulinic acid
  • 1997
  • Ingår i: Lasers in Surgery and Medicine. - 0196-8092. ; 20:3, s. 272-279
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and Objective: Laser-induced fluorescence was studied in normal and tumour tissue of rat after intravenous injection of delta-amino levulinic acid (ALA). The aim of the study was to investigate the protoporphyrin IX accumulation in different tissue types in rat after systemically administered ALA. Study Design/Material and Methods: A malignant rat tumour and normal tissue from 13 different organs were investigated in eight rats. The rats were injected with two different ALA doses, 30 and 90 mg/kg b.w., and the investigations were performed at 10, 30, and 240 min after the injection. The fluorescence was recorded utilising an optical fibre based fluorosensor at 405 nm excitation. Results: Fluorescence spectra were recorded in the 400-750 nm wavelength region including the dual-peaked PpIX fluorescence at about 635 and 705 nm, and the tissue autofluorescence peaking at about 500 nm, The maximum tumour build-up of PpIX was achieved already in less than 1 hr after ALA injection. The fluorescence demarcation between tumour and surrounding tissue was a factor of 7-8:1 after 30 min and decreased for longer retention times. The accumulation in 13 different organs was investigated and a particularly high PpIX build-up was found in stomach and intestine. Conclusions: Fluorescence detection following i.v. injection of ALA provides attractive diagnostics for the experimental tumour used, indicating clinical usefulness. (C) 1997 Wiley-Liss, Inc.
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