Abstract: Device and method for measuring the absorption of radiation in a portion of tissue. For monitoring tissue and/or in order to permit medical indications, it is necessary to gather parameters allowing an assessement of the condition of the tissue, especially with regard to its oxygen supply. The disclosed invention provides a sensor carrier (1) at the loose end of which a sensor device (2) is mounted. This sensor device carries sensor areas (5, 6) which are connected to a measuring instrument (4). Light is emitted from a sensor area (5) and received by a sensor (6) after having transilluminated the tissue. The disclosed invention may be used for examining and controlling the tissue, for example, for perinatal measurement of arterial oxygen saturation of the fetus.