Not too long ago, lasers were an almost mythical concept that belonged exclusively in science fiction. However, they have actually become extremely common and useful tools for many professions.
In medicine, the usage of lasers has allowed for revolutionary new techniques and procedures. Consequently, many diseases and conditions that were considered untreatable fifty years ago are now under our control. Here is an introduction to exactly how lasers are used within medicine:
How does laser surgery work?
Medical lasers operate similarly to improved scalpels, but they also offer higher precision and variable intensity. Medical lasers are much more powerful than laser pointers or barcode scanners, which allows them to cut through skin or other material.
A common example is laser eye surgery, which involves the user of a laser to modify the eyes of the patient. Laser eye surgery generally results in vastly improved vision, which is just one of many applications of medical lasers.
There are three central aspects of lasers which contribute to their medical effectiveness, which are the photoablative effect, the photochemical effect, and the photothermal effect.
What is the photoablative effect?
When an excimer (ultraviolet) laser is used on tissue, it will destroy or damage that tissue. The primary application of photablation is in eye surgery and reshaping of the cornea.
What is the photochemical effect?
When certain substances come into contact with specific kinds of light, they can react to create new and potentially dangerous substances. This may not seem particularly useful at first glance, but it is actually an extremely common method of eliminating tumors.
First the patient is given a substance known as a photosensitizer. The tumor absorbs this substance, and is then bombarded with laser light. Some of the light penetrates the tumor, which leads to a reaction with the photosensitizer. This reaction produces a toxic material which is meant to kill the cancerous cells.
What is the photothermal effect?
This mechanism is somewhat similar to the photochemical effect in its usage in eliminating tumors, but the two differ in several key ways. Like the photomechanical effect, the photothermal effect relies on the insertion of a photosensitizer into the tumor to be killed.
However, while the photochemical effect users lasers to synthesize a new substance within the tumor, photothermal treatments use lasers to excite the photosensitizer. At this excited state, the substance will have very high heat and vibrate rapidly. The intended outcome is for the vibrations to kill the tumor in question.