| 1. |
- af Klinteberg, C, et al.
(författare)
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Laser-induced fluorescence diagnostics of basal cell carcinomas of the skin following topical ALA application
- 1996
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Ingår i: Optical Biopsies and Microscopic Techniques, Proceedings of. - : SPIE. - 0819423289 ; 2926, s. 32-40
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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. |
- Filippidis, G, et al.
(författare)
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Effect of liquid nitrogen and formalin-based conservation in the in-vitro measurement of laser-induced fluorescence of peripheral vascular tissue
- 1997
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Ingår i: OPTICAL BIOPSIES AND MICROSCOPIC TECHNIQUES II. - : SPIE. - 1996-756X .- 0277-786X. - 0819426296 ; 3197, s. 27-31
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Konferensbidrag (refereegranskat)abstract
- In order to investigate the effects of conservation in liquid nitrogen and formalin on peripheral vascular tissue (abdominal aortic, femoral and flank artery tissue) laser-induced fluorescence spectra were recorded during the exposure of these tissues to He-Cd radiation (442 nm). The spectral distribution of tissue fluorescence allowed the development of simple algorithms based on the intensity difference in order to discriminate the tissue samples when they were fresh and after they were stored for 24 and 48 hours in liquid nitrogen or formalin.
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| 3. |
- Stenberg, M, et al.
(författare)
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Interstitial photodynamic therapy - diagnostic measurements and treatment in rat malignant experimental tumours
- 2000
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Ingår i: OPTICAL BIOPSY AND TISSUE OPTICS. - : SPIE. - 1996-756X .- 0277-786X. - 0819438170 ; 4161:32, s. 151-157
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Konferensbidrag (refereegranskat)abstract
- A recently developed multiple fibre system for treating malignant tumours with interstitial photodynamic therapy was used in studies on rats with colon adenocarcinoma inoculated into the muscles of the hind legs. The animals were intraperitonially administrated delta -aminolevulinic acid (ALA), which is metabolised to protoporphyrin IX (PpIX) in the tissue. The treatment system consists of a laser light source, a beam-splitting system dividing the light into three or six output fibres and a dosimetry programme calculating the optimal fibre position within the tumour as well as the treatment time needed to obtain a given threshold value of the light dose. One aim of the study was to compare the treatment outcome with the modelled dosimetry predictions. Tumour reduction was examined three days post treatment. A volume decrease was found in 85\% of the treated tumours. The mean volume reduction was 44\%, with one tumour completely disappearing. Histopathological examination three days post treatment showed substantial necrotic parts which, however, to a smaller extent were present also for non-treated tumours. These results indicated that the tumours have been under treated and the light dose has to be increased. Measurements of the build-up and photo-induced bleaching of PpIX using laser-induced fluorescence were also performed during the experiments.
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