Abstract

In a sensor arrangement for direct or indirect optical determination of physical or chemical parameters, in human and animal bodies, the sensor arrangement including an indicator cell which is permeable to the chemical substance or physical quantity to be measured and which contains one or more indicators, a radiation source supplying the excitation radiation for the indicator, and a detector for detection of the response radiation emitted by the indicator, the indicator cell is configured as a capsule which may be introduced into body cavities, such as mouth, nose, stomach, intestine, blood vessels, bronchial tubes, urinary bladder, or which may be implanted in the tissue, and the material used for this capsule is transparent to excitation radiation and to the response radiation emitted by the indicator in the range of wavelengths between 600 and 1,300 nm, and the material of the capsule, or rather, its outer layer, is bio-compatible.