Lasers have been used in medicine for over 30 years, e.g. in ophthalmology for treating retinal diseases, or in dermatology for treating carcinoma. Laser radiation is introduced into the body via thin, flexible quartz fibres and used to perform endoscopic surgeries.
Lasers in operating theatres
Laser surgery having become a treatment standard in some medical disciplines comes with the question of safety. One concern is whether stray radiation can reflect off specular OR materials such as luminaire surfaces and harm people. Eye damage in particular can be irreparable. The answer is that any damage depends on the power as well as wavelength of the laser radiation, and on whether the power is pulsed or emitted continuously.
Based on hazardous potential, lasers are categorised in classes 1, 2, 3A, 3B and 4. Direct radiation from class 1 and 2 lasers is harmless, just as class 3A radiation. Diffuse class 3B radiation is also harmless. Class 4 lasers are high-power lasers and hazardous in any aspect. Any exposure to radiation can damage eyes and skin. Lasers used in ophthalmology and surgery belong to this class. According to medical device legislation (national implementation of several EC directives on medical devices, particularly 93/42/EEC of 14.06.1993), these lasers are classed at the most hazardous level with the strictest safety provisions.
Laser surgery starts with a low-power adjustment laser without any hazards to the surroundings. After that, the high-power laser with extremely focussed rays is directed onto the adjusted part of the body and can remove cancerous body tissue in the shortest amounts of time.
Safety for patient and treatment personnel is achieved, among other things, as follows:
Special low-reflectance surgical instruments are used.
In terms of avoiding laser power reflection, the surfaces of surgical instruments are categorised as uneven, matt or absorbent. Uneven, irregularly structured surfaces as well as matt surfaces scatter the incident power and thus reduce the scattered power density. Concave (focussing) and extremely even surfaces which deflect directed reflections of stray radiation must be avoided. The reflective behaviour depends on the laser’s wavelength. Depending on their structure, surfaces that visually appear uneven can still function as a "mirror" for long-wave laser radiation (e.g. CO2 lasers with a wavelength of 10,6 μm).
The surgical team wears laser safety glasses.
Curtains around the OR table avoid stray radiation.
Intense beam focussing means highly reduced beam divergence, and consequently beam power disintegrates at very short distances from the laser scalpel.
Implementing and monitoring special safety measures is the responsibility of the laser safety officer of the hospital where the laser surgery is performed. The officer must be consulted in any case.