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Biomedical subjects

U Klingbeil

Publications and source records attributed to U Klingbeil.

7 recordsLinked to original sources
PubMed1996

In vitro studies and computer simulations to assess the use of a diode laser (850 nm) for laser-induced thermotherapy (LITT).

BACKGROUND AND OBJECTIVE: This study investigated the feasibility of 850 nm diode laser-induced thermotherapy (LITT), a new procedure providing local hyperthermia and photocoagulation, a minimally invasive treatment of tumors, and other disorders such as benign prostate hyperplasia. STUDY DESIGN/MATERIAL AND METHODS: An improved fiber optic diffuser inserted through a catheter was used to irradiate prostate, liver, and kidney tissue in-vitro. Experimental results were compared with predictions from mathematical simulations based on measured optical tissue parameters. RESULTS: After 10 minutes of irradiation with 2-4.6 W CW laser power, sizable coagulation diameters had been achieved. In prostate and kidney tissue, temperature rises and coagulation diameters after laser irradiation were found to be smaller than in liver tissue. Those tissues also had a higher threshold for carbonization, thus reducing the risk of damage to the delivery system. CONCLUSION: The data suggest that a low power diode laser can be recommended for use in LITT to treat prostate and kidney tissue.

Animals↗
PubMed1986

Reproducibility of optic disc measurements with computerized analysis of stereoscopic video images.

Computerized digital image analysis of the optic nerve head was performed using a simultaneous stereoscopic video camera system to provide rapid, quantitative measurements of optic nerve head topography. Determination of the variability of the measurements is required to estimate the magnitude of optic nerve change over time that can be reliably detected. Total variability, operator variability, and interoperator variability were studied. Total variability was assessed by analyzing ten sets of video recordings made in each of seven eyes of seven normal subjects, and in seven eyes of seven patients with glaucoma. The median coefficients of variation for measurements of total variability in glaucoma patients were as follows: vertical disc measurement, 1.4%; horizontal disc measurement, 2.1%; disc area, 1.9%; vertical cup/disc, 3.9%; horizontal cup/disc, 3.3%; disc rim area, 7.5%; and volume, 7.6%. Operator and interoperator variabilities were considerably smaller in magnitude.

Data Display↗
PubMed1986

Safety aspects of laser scanning ophthalmoscopes.

Safety standards such as American National Standards Institute Z-136.1 do not give clear light-level limitations for laser scanning ophthalmoscopes. To have more than a rough estimation the retinal temperature rise due to intraocular scanning laser illumination was calculated on the basis of a thermal model. The predicted temperature development with time was compared with the calculated effect of other retinal illumination patterns with well-known hazard risks. The similarity of the thermal effect of retinal scanning and extended-source pulsed illumination is discussed and used to give maximum permissible light-level recommendations for the safe use of laser scanning ophthalmoscopes.

Body Temperature↗