The relationship between lasers and medicine has had its ups and downs over the years. The reasons include unfulfilled promises by researchers and laser makers and unrealistic expectations on the part of the end users or investors. Things are changing though, and FDA-certified therapeutic applications of lasers now range from general and cosmetic surgery to ophthalmology. Their success has pushed the stock prices of many medical-laser firms well out of the doldrums. In fact, worldwide sales of nondiode lasers for medical therapy should reach $340 million this year, making medicine the second-largest application for nondiode lasers after material processing (see Laser Focus World, Jan. 1998, p. 78).
Ophthalmology is one of the largest medical applications and has received a significant boost in the past few years thanks to photorefractive surgery that reshapes the cornea and permanently corrects many vision problems. The short-pulse UV output of excimer lasers has been a key factor in making the technique possible; this month`s Back to Basics feature examines the theory and design of this laser type (see p. 131). Another medical application is photodynamic therapy (PDT). In this case, a photosensitive dye is used to localize cancer treatment both inside and outside the human body. Now, recent developments in diode-based light sources are likely to make use of PDT more widespread (see p. 139).
Meanwhile, on the diagnostic medical front, lasers are also gaining acceptance in certain areas and will be seen increasingly in clinical laboratories for routine testing. Applying spectroscopic analysis to tissue presents its own set of unique challenges but appears likely to offer early detection of certain diseases--Raman spectroscopy, in particular, may provide enhanced in vivo detection and diagnosis (see p. 83).
Asia still shows promise
The "Asian financial crisis" has been with us now for more than six months, with many observers offering their interpretation of what the real impact will be on the US economy. Regardless of the specifics, there seems little doubt that the impact will be generally negative. Within the lasers and optoelectronics industry, however, applications in the semiconductor and display industries, seem poised to provide a buffer against the crisis. The change to 0.25-µm features and smaller will drive acquisition of new optical lithography equipment, for example, while the flat-panel-display industry is increasing its purchase of laser-based annealing equipment. A review of the situation throughout Asia begins on p. 113.