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- Andersson-Engels, Stefan, et al.
(författare)
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Autofluorescence of various rodent tissues and human skin tumour samples
- 1987
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Ingår i: Lasers in Medical Science. - 0268-8921. ; 2:1, s. 41-49
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Tidskriftsartikel (refereegranskat)abstract
- Fluorescence spectra from different organs in rats and mice have been recorded to explore the potential of non-intrusive tissue diagnostics. The fluorescence was induced by a nitrogen laser that emitted at a wavelength of 337 nm. Optical multichannel techniques were used for the detection. Spectra are given from 19 different sites in Wistar/Furth rats, including an inoculated malignant tumour. The spectra seem to be a sum of two wavelength distributions only, each distribution occurring with a different weight in different organs. Spectra obtained from living and dead tissue were compared to verify that the measurements on sacrificed experimental animals were valid. Preliminary results are given for some human tumours, transplanted in nude mice, and for some human skin samples.
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| 6. |
- Andersson-Engels, Stefan, et al.
(författare)
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Identification of brain tumours in rats using laser-induced fluorescence and haematoporphyrin derivative
- 1989
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Ingår i: Lasers in Medical Science. - 0268-8921. ; 4:4, s. 241-249
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Tidskriftsartikel (refereegranskat)abstract
- Laser-induced fluorescence has been used for the identification of brain tumours in rats, which have been previously given tumour-seeking haematoporphyrin derivative. A pulsed nitrogen laser (λ=337 nm) was used in conjunction with an optical multichannel analyzer. For both inoculated RG-2 and TCVC rat-brain-tumour models, the blue autofluorescence was strongly reduced in the tumour compared with normal brain tissue, and at the same time the characteristic red-drug signal increased. The contrast between tumour and normal tissue was strongly enhanced by forming the ratio between the two signals. Implications for possible improvement of tumour delineation in brain tumour surgery are discussed.
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| 7. |
- Andersson-Engels, Stefan, et al.
(författare)
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Laser-induced fluorescence used in localizing atherosclerotic lesions
- 1989
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Ingår i: Lasers in Medical Science. - 0268-8921. ; 4:3, s. 171-181
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated laser-induced fluorescence frompost mortem human arteries in order to find spectroscopic properties allowing discrimination between normal and atherosclerotic vessel wall. A pulsed nitrogen laser emitting light at a wavelength of 337.1 nm was used as an excitation source. The fluorescence spectrum from 370 to 700 nm was captured and analysed by an optical multichannel analyser. Dimensionless contrast functions were formed by using characteristic spectral features at 390, 415, 480, 580 and 600 nm. All samples were investigated in scans across a region where normal as well as diseased vessel wall appeared. The types of plaque were histopathologically divided into four groups, of which three could be singled out using one or more of our spectroscopic criteria. We also investigated the different layers of the normal and diseased vessel wall in order to determine the various contributions to the fluorescence signal. Furthermore, plasma emission spectra were recorded while ablating the normal as well as the diseased vessel wall with an excimer laser, emitting radiation at 308 nm, thus detecting the change in spectral characteristics during the ablation process down into deeper layers.
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| 8. |
- Andersson-Engels, Stefan, et al.
(författare)
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Tumour marking properties of different haematoporphyrins and tetrasulfonated phthalocyanine - A comparison
- 1989
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Ingår i: Lasers in Medical Science. - 0268-8921. ; 4:2, s. 115-123
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Tidskriftsartikel (refereegranskat)abstract
- Several photosensitizers were screened for their tumour-marking ability using laserinduced fluorescence in Wistar/Furth rats bearing subcutaneous adenocarcinomas inoculated in muscle. Of the studied photosensitizers, dihaematoporphyrin ether appeared to exhibit the best tumour-demarcation properties. Polyhaematoporphyrin ester and tetrasulfonated phthalocyanine were almost as good although the fluorescence yield was much lower. Monomeric haematoporphyrin also showed some tumour-marking qualities. By forming fluorescence intensity ratios, information from both the blue and the red spectral regions were used to provide the highest tumour-to-muscle contrast. Two excitation wavelengths were used, of which 337 nm rather than 405 nm excitation light seemed to yield a better tumour demarcation, due to a greater difference in the superimposing autofluorescence between tumour and surrounding tissue. The study included measurements on many inner organs in an attempt to gain a better understanding of the interaction between the drugs and various kinds of tissue.
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