High energy long duration frequency-doubled Nd:YAG laser and application to veins occlusion

Laser treatment represents an attractive option to other methods of vessel diseases especially varicose veins. A long pulse (30 similar to 50ms) 532nm laser (Fig.1) is used in our experiments with the pulse duration matching the thermal relaxation time of the vessels and the green laser matching the absorption spectrum peak of the blood. Laser irradiates nude vein vessels directly or exterior skin to finish operation faster and to acquire the practical data for upper enteron varicose vein treatment in several animal experiments performed in vivo. The 5J-energy pulse allows us to finely occlude rabbit or dog's vein vessels up to 2 mm in diameter when irradiating them off external skin (Fig.2). Blood vessels are occluded at once and later biopsy specimens show the immediate and long-term lasting occlusion effect. While irradiating vessels directly (Fig.3), the vessels are usually irradiated to perforate, detailed causes are still under investigation. Animal experiments show long pulse green laser therapy is a safe and effective solution to the vein's occlusion, which promises such laser with high energy of each. pulse and 30 similar to 50 ins duration is an ideal candidate for vessel diseases treatment.