Abstract: The invention pertains to a measurement device comprising two sensors for measuring radiation doses. The sensors are, for example, optical waveguides aligned along a straight line. One of the optical waveguides covers a longer section along the line than the other waveguide; in particular, the difference is at least 20 mm. Measurement using the measurement device is done as follows: the radiation dose along the line of radiation down to the expected penetration depth is measured using the wider sensor; the narrower sensor is used to determine the radiation dose in a volume element within the radiation path. A quotient is formed from the two measurements and used to calculate the radiation depth on the basis of reference values. The proposed device facilitates rapid and simple determination of a penetration depth of an ionizing radiation, for example in tissue.

Abstract: A sensor for a tissue-equivalent radiation dose comprises a light waveguide sensitive to radiation and in a field of radiation. The waveguide is mirrored at both ends so that the back and forth passage of light takes place a multiplicity of times and a light waveguide acts as a multipath cavity. The light is coupled into and out of the waveguide at an end thereof and the ends of the waveguide can be pointed.

Abstract: A process and measuring device for determining the tissue-equivalent dose in radiotherapy. First, the radiation dose is measured according to the process at a site by at least two sensors i and j. The sensors are designed such that the associated measuring signals S.sub.i and S.sub.j display different energy dependency of the detection sensitivity to ionizing radiation, a dose-independent quotient Q.sub.ij =S.sub.i /S.sub.j being formed from this difference. The tissue-equivalent dose D is then calculated from this dose-independent value. The advantages of this process are that the sensor material does not have to be adapted to the tissue and can therefore be freely selected, and the tissue-equivalent dose is determined highly accurately. The measuring device comprises three parallel fiber-optic sensors disposed equidistant in a plane, the outer sensors being identical and differing from the central sensor by differing energy dependency of the detection sensitivity to ionizing radiation.