The use of radiometers for biomedical applications needs a coherent understanding of thermal signals emitted by the tissues. In this paper, we show first, that some precautions have to be taken when measuring a temperature by the classical radiometric method. For instance, the signal emitted by a lossy material depends on its temperature, permittivity and thickness. This remark allows us to find out a new method for measuring microwave permittivity of liquids when using a Dicke radiometer. We propose a modified radiometric method to determine directly the temperature of the material whatever its reflection coefficient. The applicability of this method is tested with a X band set-up including FET microwave amplifiers. Possibilities of using probes for in situ temperature measurements are discussed.
Abstract The globin of sheep heart myoglobin was first cleaved by cyanogen bromide and the resulting fragments were fractionated by gel filtration and preparative paper electrochromatography; each fragment was submitted to endopeptidase digestion and the complete amino acid sequence has been determined. The intact globin and the median cyanogen bromide peptide were analysed by the protein sequanator (Edman). This analysis confirmed the sequence of the first 46 N-terminal residues of the intact globin and established the sequence of the first 39 N-terminal residues of the median cyanogen bromide peptide. Between sheep and beef myoglobin six differences over 153 residues can be noticed; among the six amino acid replacements, two correspond to the exchange of two bases and four to the exchange of one base in the coding triplets.
Several medical fields are concerned by thermal effects of lasers. Mathematical models of thermal effects can help to define lasers parameters in relation to therapeutic use, but an exact quantification of the Nd:YAG laser induced damage is not possible at the time of the treatment. Adaptive control is proposed as a useful process for an improvement of Nd:YAG laser treatments. A computer controlled Nd:YAG laser system with a closed loop capability was developped. Infrared radiometry provided noncontact temperature measurement for real time coagulation and ablation control. The controller design is based on the predicted response, defined by mathematic models. Deviations of the actual response, beyond an established tolerance, caused the Nd:YAG laser system to adjust the laser parameters automatically.
