FIELD: medicine.SUBSTANCE: group of inventions relates to medical equipment, particularly to means for measuring optical properties of tissue in a body. Medical device comprises a probe having a distal segment configured to be inserted into a patient's body, the probe comprising at least one sensitive optical unit that is positioned along the distal segment and comprising first and second radiation sources configured to emit optical radiation in various respective first and second wavelength ranges towards the tissue in the body in close proximity to the distal segment, and an optical sensor configured to receive optical radiation in the first and second wavelength ranges that is scattered from the tissue, and output first and second electric signals in response to the intensity of the received optical radiation. Method of optical assessment of tissue damage is carried out according to a first version through operation of the device. In the second version, the method for optical assessment of tissue damage is performed by applying radio-frequency (RF) electric energy in such a way as to create a lesion on the tissue site within the patient's body, measuring a first intensity scatter on the site in the infrared radiation range and a second intensity scatter on the site in the red radiation range when RF electric energy is applied, and assessing lesion formation by comparing the first intensity scatter and the second intensity scatter.EFFECT: use of the group of inventions makes it possible to improve the accuracy of measuring optical properties.26 cl, 4 dwgГруппа изобретений относится к медицинской технике, а именно к средствам измерения оптических свойств ткани в теле. Медицинское устройство содержит зонд, имеющий дистальный сегмент, выполненный с возможностью введения в тело пациента, причем зонд содержит по меньшей мере один чувствительный оптический блок, который размещен вдоль дистального сегмента и содержит первый и второй источники излучения, выполненные с воз
