Abstract: Apparatus intended for the injection of pulsed steam into a human or animal vessel comprising an injection unit sending pulses of cold water into a handpiece, a handpiece temporarily attached to an injection unit within which there is a metal tube, of external diameter between 200 ?m and 1,000 ?m and internal diameter between 100 ?m and 500 ?m, the metal tube having its distal end coiled to form a spiral, the tube being sheathed with a material of resistivity such that only the spiral heats to a temperature transforming water from the liquid phase into the vapor phase, a means of distributing the steam into the vessel intended to be connected in a reversible manner to the distal end of the handpiece.