Physics applications of lasers in medicine

It is hard to imagine that a narrow, one-way, coherent, moving, amplified beam of light fired by excited atoms is powerful enough to slice through steel. In 1917, Albert Einstein speculated that under certain conditions atoms could absorb light and be stimulated to shed their borrowed energy. Charles Townes coined the term laser (light amplification by stimulated emission of radiation) in 1951. Theodore Maiman investigated the glare of a flash lamp in a rod of synthetic ruby, creating the first human-made laser in 1960. Although lasers are today used by a large variety of professions, one of the most meaningful applications of laser technology has been through its use in medicine. Being faster and less invasive with a high precision, lasers have penetrated into most medical disciplines during the last half century including dermatology, ophthalmology, dentistry etc. In many ways the laser has revolutionized the diagnosis and treatment of a disease. As a surgical tool the laser is capable of three basic functions. When focused on a point it can cauterize deeply as it cuts, reducing the surgical trauma caused by a knife. It can vaporize the surface of a tissue. Or, through optical fibres, it can permit a doctor to see inside the body. Lasers have also become an indispensable tool in biological applications from high-resolution microscopy to subcellular nanosurgery. Indeed, medical lasers are a prime example of how the movement of an idea can truly change the medical world. This thesis will survey various applications of lasers in medicine. This work gives an idea about the originality of laser beams and how we benefit from them in the treatment and the recovery of patients. Some of the important medical lasers are Neodymium- YAG Laser (Nd: YAG) is used in laparoscopic surgery, the Carbon Dioxide Laser (𝐶𝑂2) is one of the most widely used in surgical operation especially in gynecologic surgery. Moreover it is used as scalpel, the Argon Laser (𝐴𝑟+) is used for ophthalmology and the Dye Laser is recently used in the treatment of cancer tumor. We know that Argon and Dye Lasers beams produce intense visible light that can be seen by the naked eye. For this reason they can be easily controlled and directed by the surgeons and physician. But beams of Carbon Dioxide and YAG Lasers are invisible and they are located in the Zone of the infrared region. For this reason we use the beams of Helium Neon lasers that have red colour with energy very low.