An apparatus for cooling tissues which are treated with an energy-based device, such as a laser, is disclosed. The apparatus comprises a spray nozzle which generates an atomized liquid spray for the treatment area, wherein the atomized liquid spray is based on a mixture of liquid and gas. Further, the spray nozzle comprises at least one liquid outlet which ejects a liquid, and at least one gas outlet which ejects a gas stream. Besides, the apparatus for cooling comprises at least one delivery means for delivering pressurized gas to the spray nozzle； and a pumping means for the liquid, wherein the pumping means is configured to operate in pulses.
