Page 173 - Veterinary Laser Therapy in Small Animal Practice

Considering laser therapy for your practice 159

of Tennessee, so picture me saying that in a hillbilly, of danger and medical legal precautions. While it is
tobacco-spitting, moonshine-sipping, overall-wearing absolutely necessary to disclose this list to your patients
twang.) But seriously … (and staff), it is useful to understand the actual dangers
Safety concerns have been thoroughly evaluated in each situation. Our version of the contraindications
by governing bodies (Food and Drug Administration of LT is as follows:
[FDA], Health Canada, Conformité Européen [CE]
Marking, etc.) and international organizations (WALT, • exposure to the eyes (main and absolute
NAALT, etc.) via thermal tests, histology reports, contraindication)
and other worst-case scenario experiments. They all • known malignancies (although this paradigm may
reach the same conclusions: LT is one of the safest in change in the future)
the world and undesired effects can be avoided if the • gravid uterus
therapist is educated. Reported side effects, (e.g. tired- • the thyroid (relative)
ness, nausea, headache, and increased pain) are always • in local combination with steroid/NSAID injection.
described as mild and actually have a prevalence similar
to those in the placebo group when studied in humans. Other situations, such as active growing epiphy-
[100] Thousands of treatments are performed worldwide ses or epilepsy, are not contraindications per se, but
each day in human and veterinary patients. Safety is one precautions need to be taken and discussed with the
of the reasons why LT is growing so fast. Having said owner. Let’s explain in more detail, since knowing why
this, every practice should be strict in their adherence to the limits are in place and where their boundaries are
safety procedures when using laser. And knowing about enables you to extend the range of your applications
safety is important even before you acquire a device. safely and effectively.
Each country may have their own specific regula-
tions for the safe use of laser devices, but all of them 10.2.1 Eye exposure
include eye protection, warning signs, and staff/pet
owner education, among others. Being an educated The eyes contain the most photosensitive cells in your
laser user you will know why safety is important, but body. This fact alone should throw up some red flags
also how to erase any superstition related to this type of when dealing with high-powered light sources like
infrared electromagnetic radiation. lasers. But the most crucial feature of the eye relevant
to safety is the lens and its focusing power. Briefly,
whatever light that is not absorbed or reflected by the
Basic facts cornea passes through the lens and gets focused onto
the retina, and in particular a central spot known as the
• Red and infrared lasers are non-ionizing, just fovea centralis, which then connects to the brain, where
like your infrared lamp in the intensive care
unit, or the fluorescent bulb over your head. the light gets processed and interpreted as an image.
• You are using a very special type of lamp, but For a given wavelength of light, the laser param-
a kind of a lamp nevertheless; when you turn eter that dictates the safe/dangerous limit is power
2
it off, there is no radiation floating around or density (W/cm ; i.e. the amount of energy delivered
remaining in the room or in objects. per second per unit area). Note: power alone says
• In LT, we do not vaporize cells, or cut or burn nothing about safety, since light from a 100 W lamp
the patient. That is done with other types of spread over an entire room is perfectly safe but light
laser, coagulation devices, and laser sabers. from a 0.5 W laser delivered through a 0.001 cm fiber
Therefore, there is no toxic plume to be can do surgery.
evacuated. Once an external power density of 1 W/cm (one
2
that is perfectly safe for any tissue in your body) is
There is no universally endorsed contraindication focused by the lens, the retina is exposed to a power
list, however, and some of the conditions laser com- density of over 80 W/cm . This amount of focused
2
panies and training organizations include do not come energy can cause irreversible damage to the eye and
from negative data points from any studies. Instead, can lead to partial or total blindness. You can see that
this list is created mostly from theoretical possibilities even scattered light from high-powered sources poses

REDONDO PRINT (4-COL BLEED).indd 159 08/08/2019 09:48