Alternative Energy Sources and Laser Biophysics

These vocabulary flashcards cover alternative surgical energy sources, laser biophysics, tissue interactions, and the specific characteristics of various medical lasers.

Harmonic scalpel

A device that cuts and coagulates by using mechanical vibrations at a rate of $55,500\,\text{times/sec}$ to separate tissues and denature proteins.

Plasma Vaporization

A technology using bipolar current and ionized particles to vaporize tissue without direct contact, often used to treat benign prostatic hypertrophy.

LASER

An acronym standing for Light Amplification by the Stimulated Emission of Radiation.

Monochromatic

A property of laser light where all photons that compose the light are the same color or wavelength.

Collimated

A property of laser light where waves are parallel to each other and do not spread out as they travel away from the source.

Coherent

A property of laser light where waves travel in the same direction, which increases amplitude and power.

Fluence

A term referring to the precision of the laser beam, determined by properties such as spot size, Watts, Joules, and time.

Joule

A measurement of laser pulse energy based on a $1\text{-second}$ amount of time the beam is activated.

Absorption

A laser-tissue interaction causing thermal damage that depends on fluence, wavelength, tissue color, and cellular water content.

Transmission

The process of a laser beam traveling through a medium, such as glycine or vitreous humor.

Reflection

The bouncing of a laser beam off an impact site, which can cause harm to inadvertent tissue or be intentionally diverted.

Scattering

Occurs when the angle of reflection is equal to the angle of oncoming light, causing the laser beam to spread unpredictably.

Backstop

Material used to prevent damage from laser reflection, such as a wet sponge, titanium, or quartz rods.

Gas active media

Media energized by electricity to produce laser light, including examples like $CO_2$, $He-Ne$, Krypton, Argon, and Excimer.

Solid active media

An energy-producing element on a rod energized by flash lamps, such as Ruby and $Nd:YAG$.

Liquid active media

Organic dye energized by a laser beam to produce light, such as that used in a Tunable Dye laser.

Semiconductor crystal

A medium where laser energy is delivered directly to tissue through a filter.

Tunable Dye Laser

A laser using a liquid medium that produces a green color and is used for shock-wave lithotripsy.

CO2 Laser

The most frequently used laser that permits cutting and coagulating; it is absorbed by cellular water and requires a red $He-Ne$ aiming beam.

Diode Laser

A laser that generates radiation through a semi-conductor using electric current, optimal for vascular areas and soft tissue ablation.

Nd:YAG and Holmium:YAG

Solid crystal lasers absorbed by darker pigmented tissue; they utilize invisible wavelengths and require a $He-Ne$ laser aiming beam.

KTP Laser

A crystal of potassium-titanyl-phosphate that produces a visible green beam highly absorbed by blood vessels and tattoo ink.

Erbium (Er:YAG) Laser

A laser used for skin resurfacing and re-epithelization of dermal layers as an alternative to chemical peels.

Krypton Laser

A gas laser that produces green, yellow, and red beams, with red being the most frequently used color.

Excimer Laser

An ultraviolet gas laser used to reshape the cornea or destroy plaque; note that the gases used are toxic.

Argon Laser

A laser with a blue or green visible beam that can travel through clear fluids, useful for treating diabetic retinopathy.

Laser Plume

The smoke produced during laser use containing toxins, particles, and biological debris (blood, bacteria, DNA) that is potentially carcinogenic.