Experimental Study Of Treatment Of Skin Pigmented Disease By Q-Switched Double Laser Pulse

Nowadays, laser medicine is one of the fastest development medical fields. Laser is used widely to cure the dermatosis because of its admirable directivity, monochromatic, coherence. Especially in the field of pigment skin disease therapy, Q-switched laser is used broadly because of the proved selective photothermolysis, which can eliminate the pigment in skin effectively and avoid the injury to the normal skin tissue effectively.However, during the research of Q-switched single pulse, we find that we can increase the single pulse output energy by increasing the pumping rate, make the pulse duration narrower, and greatly improve the output power and the curative effect. But the high power laser can aggravate the second pressure effect what is called sound damage made by sound transient. And the method may lead laser medium and laser device damaged. Thus, improveing the laser energy contradicts the decrease of the tissue injury and the danger of laser device damaged.In theory, using Q-switched double or multiple pulse laser therapy the pigment skin disease can make laser energy radiate twice or more. Thus, if the pulse duration is not changed, Q-switched double pulse laser can have the same output power as Q-switched single pulse laser, at the same time decrease the danger to make the laser device damaged. But is the curative effect of using Q-switched double pulse laser therapy the pigment skin disease similar as that of Q-switched single pulse? What factors can affect the curative effect? The paper made the research with the direct as the above said.1 The interaction between laser and the skin tissue was studied. The calorific quality of skin was studied in laser therapy. A model for heat exchange in skin tissue was set up. With the model, we discussed the reason for the calorific or sound damage of the skin tissue by Q switched laser.2 After the research of the basic knowledge of Q switched laser and skin pigmented disease, we compared the effect of the Q-switched single laser pulse with that of Q-switched double laser pulse to the black tattoo by the animal experiment. At the same time we researched the effect of energy density and pulse interval to the curative effect of the Q-switched double pulse through the data analysis. At last, we found that the curative effect of the Q-switched single pulse and double pulse was similar at the same energy density and that the skin injure of the Q-switched double pulse was less than the Q-switched single pulse.3 On the basic of researching the biological active mechanism of the mutual action of the skin and the Q-switched single and double pulse, we put forward the principle that treating pigment skin diseases by the Q-switched double pulse can alleviate the skin injure on the premise of not improving the laser peak power. At last, we made the simple mathematic analysis.