In the years following the demonstrations of the first working lasers in the early 1960s a flurry of speculation emerged, predicting medical applications of lasers that were both fanciful and unjustifiably optimistic. As the laser industry emerged and grew, a number of the companies opened medical laser divisions, received FDA approval for surgical lasers and began marketing them to hospitals and surgical group practices. These were generally high-power continuous lasers, often Nd:YAG lasers operating in the NIR at 1.06 μm, or their frequency-doubled version at 532 nm. Little in the way of statistically powered research had been carried out to determine whether these “laser scalpels” could actually achieve better patient results than traditional surgical tools. While some laser wavelengths, at appropriate power levels, can indeed achieve improved degrees of hemostasis (stoppage of bleeding), this can also be accomplished with an electrically heated scalpel blade, which cauterizes as it cuts, and at much lower cost. The introduction of a new technology is at its best when it enables a process or procedure that cannot be accomplished by other means, or that accomplishes the objective more efficaciously or at lower cost. This was not always the case in those early days of medical lasers, and within a few years many hospitals had large, expensive laser systems gathering dust in closets.

One example of an application that originally inspired optimism but has fallen out of favor is laser angioplasty: the use of high-power pulsed lasers to ablate atherosclerotic blockages, thereby restoring blood flow in coronary arteries. Initial studies in the 1980s indicated that acute response was promising, with immediately restored blood flow. Restenosis was found to occur within months, however, in almost all cases, often with blockages worse than the pre-procedure condition (Sanborn, 1996). It was eventually determined that the new blockage was a result of the local infiltration (and proliferation) of smooth muscle cells, released due to the absence of the protective endothelium (the layer of cells that line the inner surface of blood vessels), which of course was also ablated while removing the plaque (Köster et al., 2002).

Low-power lasers, however, have facilitated novel methodologies in re-search for cellular biology, with an explosion of applications enabled by the development of optical tweezers, which offer precision manipulation of particle location and measurement of piconewton forces.