1. Medical ultrasonic device, comprising: an elongated body (3) having a proximal end (90), a distal end (10), a distal end region (1) and an axis (9) extending in length along the extension direction； - one or several ultrasonic transducers (4) for generating acoustic radiation located in the region of the distal end inside the elongated body； - a transmitting element (5) located on the path of the acoustic radiation rays, which is essentially transparent to acoustic radiation； - control unit (91),functional- associated with the ultrasonic transducer, wherein the control unit is adapted to detect the acoustic path length through the transmission element and determine the temperature at the distal end on the basis of a certain acoustic length puti.2. The device according to claim 1, in which the transmitting element has a rear side (21), mainly directed to the ultrasonic transducer, and the opposite front side (22), and the temperature at the distal end is determined based on recording the distance between the reflection peaks (40, 41) from the surface of the rear side of the transmission element and the surface of the front side of the transmission element. 3. The device according to claim 1, in which the region of the distal end further comprises channels (7) for the fluid, which allow the delivery of fluid through an elongated body to the region of the distal end. The device according to claim 1, in which one or more ultrasound transducers are capable of generating acoustic radiation suitable for monitoring the region of interest and recording the acoustic path length through1. Медицинское ультразвуковое устройство, содержащее:- удлиненное тело (3), имеющее проксимальный конец (90), дистальный конец (10), область дистального конца (1) и ось (9), проходящую по длине, вдоль направления удлинения；- один или несколько ультразвуковых преобразователей (4) для генерации акустического излучения, расположенных в области дистального конца внутри удлиненного тела；- передающ
