Friday, February 24, 2006

Medical Lasers—Breaking New Ground

Lasers are indispensable for many medical applications today including aesthetic, dental, ophthalmic, and biotech. Technologies related to lasers continue to push the boundaries. One trend is the shift to fiber-based lasers away from optic resonators. These lasers use fiber optics to generate laser beams rather than the traditional optic resonator method which eliminates alignment, thermal, contamination, and other issues. Fiber lasers are much more efficient than conventional lasers. Other advantages include lower operating cost, no maintenance cost (no diodes or flashlamps to replace), smaller size, and smaller spot diameters. Optical fibers can be used to bring the laser to the target area which may be inside the human body. In this article, MIT Review describes how researchers used a semiconducting material within the fiber line to detect defects in the fiber casing and shut down the laser to prevent leakage.


Tunable lasers solve numerous applications including assessing airway passages in lungs without the need for reagents to measure exhalation particles. Ekips Technologies, in Oklahoma developed the Breathmeter which uses mid-infrared diode lasers to measure specific molecules using the technique called vibrational absorption spectroscopy. Tunable lasers and gold nanoparticles are being used to research heart treatments. The Imperial College of London announced that lasers can also be used instead of X-rays to measure bone density by measuring the amount of collagen. The technique goes beyond measuring the strength of the bone to predicting the bone’s risk of fracturing.

The Fraunhofer-Institut uses modified femtosecond lasers for nanomedicine in which small holes are drilled into cellular membranes to transfer genes.

Raman Spectroscopy lasers are used in glucose monitoring by measuring the change in the color of light as it passes through a blood vessel. LightTouch Medical is one company (of many) who use this technique.

In the area of aesthetic lasers, Reliant Technologies uses Fractional Photothermmolysis which produces microscopic heating on the skin with space in between each microscopic spot. This leaves much of the skin in tact and thus healing time is faster.

As for lasers in the dental area, there is more work to be done. Typically, dental lasers use erbium: yttrium-aluminum-garnet (Er:YAG) to remove layers of decayed tooth and prepare it for a filling. But as this article observes, it has many limitations and is not widely used today.

In the area of ophthalmic lasers, researchers combine excimer lasers with wavefront technology which measures the reflected light in the cornea and corrects for any aberrations. Today’s machines measure about 2000 datapoints in the light coming from the eye. The FDA has cleared the technology for commercialization. Additional information can be found in this article.

Some lasers for medical applications are moving from emerging technology status to commercialization. This press release, from Genetic Engineering News predicts exponential growth of tunable lasers from $5M to $2B in six years. Research and Markets offers a research report here.

Best regards,
Hall T.