HIFU

Interpreting the four stages of laser application in medical development

Our laser was predicted to have the possibility of light amplification in 1917. The first application field of laser is medicine. Up to now, it is developing at a high speed. Laser has gone through four stages.

First stage

The 1960s was the basic research stage: most of the basic theoretical research of laser medicine was completed in the 1960s. Since the advent of the first laser, Goldman L, known as the “founder of laser medicine”, has begun to study the interaction between laser and biological tissue on the skin.

In 1961, someone tried ruby laser to weld the detached retina; In 1963, Goldman l began to apply ruby laser to benign skin damage and tattoo treatment and achieved success, creating a precedent for the application of laser medicine. In the middle and late 1960s, argon ion (Ar +) laser, low-power CO2 laser and neodymium glass laser were successively developed, but their clinical applications were few.

At the initial stage of laser research, China took the lead in the world. In 1961, Changchun Institute of Optics and mechanics developed China’s first ruby laser. In 1965, Beijing Tongren Hospital began the animal experiment of ruby laser retinal coagulation. In 1968, Shanghai developed nd  YAG (neodymium doped yttrium aluminum garnet) laser.

Phase II

The 1970s was the clinical trial stage: in 1970, Goldman L and others first used continuous CO2 laser to treat basal cell carcinoma and cutaneous hemangioma. Due to the continuous provision of effective laser power and energy density, they overcame the shortcomings of low power and low efficiency of early pulsed laser, thus setting off the first laser medical upsurge at home and abroad. Continuous CO2 laser is widely used in surgery, dermatology, facial features, gynecology, physiotherapy materials Department of acupuncture and oncology, and achieved satisfactory results.

In the 1970s, the continuous lasers used in skin cosmetology included Ar +, Cu vapor and nd:yag lasers. The thermal injury of these continuous lasers to tissues is non selective, and the treatment is often accompanied by side effects such as skin scar depigmentation, which can not achieve a good cosmetic effect.

Phase III

The 1980s was the formation stage of the discipline: in 1983, Anderson RR and Parrish JA put forward the theory of selective photothermal action, namely the theory of “photothermal separation”, which means to select the appropriate wavelength, energy and pulse duration according to the biological characteristics of different tissues, so as to ensure the effective treatment of diseased tissues and avoid damage to the surrounding normal tissues as much as possible.

This theory realizes the perfect unity of the effectiveness and safety of laser, and is a milestone in the history of laser medicine, especially laser cosmetic medicine. The pulse laser machine designed according to the selective photothermal effect has made great progress in the 1980s.