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Biomedical subjects

S Svanberg

Publications and source records attributed to S Svanberg.

50 records · Page 3Linked to original sources
PubMed1991

Fluorescence imaging and point measurements of tissue: applications to the demarcation of malignant tumors and atherosclerotic lesions from normal tissue.

The possibilities of using laser-induced fluorescence for tissue diagnostics are discussed. The tissue types investigated are malignant tumors and atherosclerotic lesions. Studies with natural autofluorescence as well as with fluorescent tumor markers are included in this paper. Fluorescence emission and decay data are presented for some tissue chromophores contributing to tissue autofluorescence. Optical spectroscopic characteristics of fluorescent malignant tumor markers are analyzed and instrumental designs for clinical applications are discussed. Images recorded with a multicolor fluorescence imaging system developed in Lund are presented.

Adenocarcinoma↗
PubMed1990

Time-resolved laser-induced fluorescence spectroscopy for enhanced demarcation of human atherosclerotic plaques.

We report on the enhanced demarcation between human atherosclerotic plaques and normal vessel wall obtained using time-resolved detection of laser-induced fluorescence rather than the customary time-integrated monitoring technique. A frequency-doubled mode-locked and cavity-dumped continuous wave dye laser was used for picosecond pulse generation at 320 nm, and photon-counting techniques were employed for the time-resolved signal monitoring from human aorta samples in vitro. Implications for imaging fluorescence angioscopy and spectroscopic guidance in laser ablation of plaque are indicated.

Aorta↗
PubMed1989

Fluorescence diagnosis and photochemical treatment of diseased tissue using lasers: Part I.

Lasers are useful in many applications in medicine and biology. Historically, most laser use has involved heat generated in the interaction of the laser beam with the tissue. Today, however, the spectroscopic aspects of this laser use are playing a more dominant role in a number of applications. In this two-part series, Sune Svanberg and co-workers present illustrations of emerging clinical applications from cooperative work performed by the Lund Institute of Technology and the Lund University Hospital. Part I includes a survey of laser techniques for atomic and molecular analyses of samples of medical interest, spectroscopic analysis of the laser-induced plasma obtained when a high-power pulsed laser beam interacts with tissue, and the use of tumor-seeking agents in combination with laser radiation to provide new possibilities for malignant tumor detection and treatment. Part II, which will appear in the January 1, 1990, issue, describes the use of laser-induced fluorescence for tumor and plaque diagnostics. Different lasers have been used, and research efforts increasingly are being focused on excimer lasers and lasers in the IR region for the ablation of atherosclerotic plaques, cell layer by cell layer.

Chromatography, Liquid↗
PubMed1986

Fluorescence studies of hematoporphyrin derivative in normal and malignant rat tissue.

Laser-induced fluorescence in rat tissue was studied during the uptake and clearing period of i.v.-injected hematoporphyrin derivative. A malignant rat tumor and normal tissue of 20 different kinds from the tumor-bearing animals were investigated. A pulsed nitrogen laser (337 nm) was used in conjunction with an optical multichannel analyzer system, in which the whole fluorescence light distribution was captured for each laser pulse. Several of the organs exhibited an initial and a delayed intensity peak in the characteristic hematoporphyrin derivative laser-induced fluorescence intensity (630 nm) that might be interpreted as due to intracellular transformations of different chemical components of the hematoporphyrin derivative preparation. By dividing the background-free 630-nm signal by the blue fluorescence intensity, a dimensionless quantity is obtained that could have many advantages in practical endoscopic laser-induced fluorescence work. This ratio was also shown to exhibit a larger contrast between tumor and surrounding tissue. The ratio between the two red fluorescence peaks was also found to be useful for discriminating tumor from normal tissue. A combination of the two ratios was shown to be particularly valuable for tumor discrimination.

Animals↗
PubMedDate not supplied

Blood perfusion studies on basal cell carcinomas in conjunction with photodynamic therapy and cryotherapy employing laser-Doppler perfusion imaging.

Superficial blood perfusion was monitored using laser-Doppler perfusion imaging in connection with a phase III clinical trial comparing photodynamic therapy, utilizing topically applied delta-aminolevulinic acid, with cryotherapy of basal cell carcinomas. A total of 526 images were recorded before and immediately after the treatment and during the follow-up period. Before treatment, the lesions exhibited a blood perfusion 3+/-2 times that in normal tissue. Both treatment modalities induced an increased blood perfusion inside the lesions, which slowly approached normal values in conjunction with successful treatments. The blood perfusion in successfully treated lesions approached normal values 2 months after photodynamic therapy, and about 1 year after cryotherapy. The tissue perfusion in recurrent lesions did not decrease to normal values after the treatment, suggesting that the laser-Doppler perfusion imaging technique can be used to follow the healing process and discover possible persistent tumour growth.

Adult↗
PubMedDate not supplied

Fluorescence endoscopy instrumentation for improved tissue characterization.

An endoscopic instrument for normal optical inspection and simultaneous fluorescence characterization is described. The equipment is primarily intended for early cancer detection using characteristic fluorescence from the tumor-seeking agent hematoporphyrin derivative. A dimensionless ratio of two fluorescence intensities is monitored making the equipment insensitive to target distance and surface topography. A measurement example is given and possible improvements are discussed.

Endoscopes↗