CLINICAL APPLICATIONS
Lasers used as scalpels and electrocoagulators have some unique
advantages. For example, lasers allow highly precise microsurgery, even in confined
or difficult-to-reach sites. Two examples of a laser system's ability to reach remote
sites effectively include percutaneous diskectomy[8]
and endovascular angioplasty.[9]
The ability to
focus laser beams on small target areas concentrates the intensity or power per area
enormously. For example,
a 10-W beam, originally with an area of 1 cm-2
, has a power density of
10,000 W/cm2
when focused on a target area of 0.001 cm-2
.
This power density delivers approximately 2500 kcal/sec to the target site, producing
heating at a rate of many thousand degrees per second, depending on the volume of
energy absorption. This allows precise, rapid vaporization of tissue and most other
materials except metals and ceramics. Lasers do not increase the energy of a particular
photon, but they place more photons at a given place and time than other light sources.
Laser surgery is relatively "dry," providing near-instantaneous sealing of small
blood vessels and lymphatics, even in the presence of clotting abnormalities. However,
early claims for faster than normal healing and lower infection rates have not been
convincingly validated.[10]
