Choosing the right medical laser

How to choose a medical laser?
What are medical lasers used for?
What effect does a laser beam have on the body?

Choosing the right medical laser

The word “laser” comes from the acronym “Light Amplification by Stimulated Emission of Radiation”. A laser is a device which, following the excitation of an amplifier medium, makes it possible to generate, by stimulated emission, a beam of coherent and monochrome photons (of identical phase and wavelength).

The generated beam is therefore an electromagnetic wave characterized by its wavelength, amplitude and the duration of its emission (pulses). These characteristics will, depending on the type of tissue, mainly determine the absorption depth and the power transmitted. These factors therefore make it possible to define the laser’s application.

How to choose a medical laser?

The criteria for choosing the right laser obviously depend on your intended use. But this is not the only factor you should consider.

It is also important to take into account the cost of the device itself, as well as the cost and time required to train caregivers.

The maintenance contracts offered by the manufacturer or distributor are also important, as is the reliability of the equipment depending on the intended frequency of use. It is important to balance cost and quality and never to make a hasty purchase without first looking into the different manufacturers and what they have to offer.

Lastly, it is essential to weigh the therapeutic value of using a laser versus another type of technology, such as radio frequency, intense pulsed light or cryoablation (using cold to destroy tissue).

What are medical lasers used for?

Several medical specialties have for some time now integrated laser technology into their daily practices:

Deka hair removal laser

Dermatology and aesthetic medicine are the most popular.
Lasers are used for tattoo removal, long-term hair removal, acne treatment and skin rejuvenation to improve and firm the skin. When it comes to hair removal, the results depend on the type of skin, given that the lighter the skin and the darker the hair, the more effective the results will be. Several sessions are necessary.

Urology also uses lasers for prostate enucleation. This minimally invasive surgery, performed endoscopically, uses a laser to remove tissue that blocks the flow of urine into the prostate. Similarly, lasers are also used in lithotripsy to destroy stones in the kidneys, bladder or ureter.

A.R.C. Laser ophthalmic laser

Ophthalmology has also seen the use of lasers become very popular, particularly for refractive surgery, which can treat various pathologies such as myopia, astigmatism, hyperopia and presbyopia. Another application is retinal photocoagulation, which consists of applying a laser beam to the deepest structure of the eye, the retina, in order to produce a therapeutic burn to a given area. Lastly, still in the ophthalmology sector, selective laser trabeculoplasty reduces eye pressure in chronic glaucoma.

General surgery also uses lasers, particularly for soft tissue ablation. Laser treatment is also increasingly being used in dental practices for early detection of cavities, gum disease, teeth whitening and lesion removal.

Physiotherapy offers laser biostimulation of cells, which represents an effective technological innovation for pain management. It consists of transferring light energy to the cell to stimulate its metabolic functions. This induces several observable clinical effects including pain relief, reduction of inflammation and healing.

What effect does a laser beam have on the body?

A laser beam can have multiple effects on the body. These essentially depend on the type of laser beam applied (the wavelength, electric field amplitude, pulse duration, beam width) and the target tissue.

There are four types of effects:

  • The thermal effect:
    Hyperthermia: the use of the laser causes a moderate increase in temperature to the target area, ranging from 41 to 44°C. This lasts a few dozen minutes. The result is cell death due to changes in the enzymatic processes. This method, which is rather difficult to control, is rarely used.

    Coagulation: this process consists in reaching a high temperature that can go from 50 to 100°C in the course of a second. This leads to desiccation (water evacuation), bleaching and shrinking of tissue by denaturing proteins and collagen.

    Vaporization: the different tissue components disappear into vapor from 100°C within the relatively short time of about one tenth of a second.

  • The mechanical effect (cavitation): this process consists in creating a thermal effect that is not diffused. The heat boils the water inside the cell and creates air bubbles that accumulate until they burst the cell in question.
  • The photoablation effect: in this case, the laser (especially in very short wavelengths) will break certain molecular bonds in the tissue and create a very clean cut without generating any heat. It is a topical, precise technique, but it does not allow for in-depth intervention.
  • The photodynamic effect: this process consists of first injecting a photosensitizing agent into a patient intravenously. When it comes into contact with the laser light, the product will absorb this energy and become toxic, in this way allowing for the treatment of the tumors it has attached itself to.

Are there any risks associated with the use of a laser?

There are some risks associated with the use of a medical laser. The main risk is retinal damage or even blindness. There is also a risk of burning the skin or other soft tissue, but this is rare. In the case of long-term hair removal, for example, the laser should only damage the hair follicle and not the skin.

However, not all lasers present such risks and this mainly depends on the class of laser used. In order to take precautions for a laser presenting risks, individual protective equipment is necessary, such as both the administrator and the patient wearing glasses. Eyes are the most vulnerable organ to lasers.

What are the different classes of medical lasers?

According to the international standard IEC 60825-1-2014, there are eight different classes of lasers, classified according to the dangerousness of the device.

  • Classes 1 and 1M: these classes concern lasers that do not represent any danger during their use, including direct vision of the beam over a long period of time. Class 1 also includes high-power lasers that are completely enclosed, so that no potentially dangerous radiation is accessible during use. This includes, for example, devices with built-in lasers.
  • Class 1C: this class concerns lasers intended for direct application of laser radiation to the skin or internal body tissue. It includes lasers used for diagnostic, therapeutic and cosmetic procedures (hair removal, wrinkle and acne reduction, etc.). Eye exposure to this class of lasers is prevented by technical means.
  • Classes 2 and 2M: these classes concern lasers that emit radiation in the visible spectrum but remain safe if the exposure is temporary (less than 0.25 seconds). They can be dangerous if you deliberately look into the beam. A warning message on the labels indicates not to look continuously or intentionally into the beam and to react actively to protect yourself, for example by moving your head or closing your eyes.
  • Class 3R: this class concerns lasers that emit radiation that can exceed the MPE (maximum permissible exposure) for direct vision into the beam. But the risk of injury in most cases is relatively low. It increases with the duration of exposure. In all cases, the use of protective glasses is strongly recommended.
  • Class 3B: concerns lasers that are dangerous when eye exposure to the beam occurs, including for short-term accidental exposure. These lasers can produce minor skin lesions or even present a risk of combustion for tissue or materials in contact with the beam. Wearing protective glasses is mandatory for these lasers.
  • Class 4: this class concerns lasers that are dangerous to look at or expose skin to. These lasers also present a fire hazard. Wearing protective glasses is mandatory.