Lasers and Flashlamps at a Glance
- Lasers are the most precise and selective surgical tools in existence.
- Nonscarring treatment of vascular lesions, pigmented lesions, tattoos, and hair follicles relies on a process called selective photothermolysis. For each of the aforementioned broad indications, there are lesion variants that are highly responsive to laser therapy, lesions that are occasionally responsive, and lesions for which laser treatment is contraindicated.
- Pulse duration strongly influences safety and efficacy, and, in general, should be approximately equal to the thermal relaxation (cooling) time of specific targets in a given patient.
- Port-wine stains are congenital neurovascular lesions best treated in early childhood that respond well, but rarely completely, to laser treatment.
- Laser treatment is useful for treatment of ulcerated infant hemangiomas.
- Fractional resurfacing is a technique in which thousands of laser microbeams per square centimeter are used to stimulate epidermal and dermal remodeling. It is a less invasive treatment for photoaging than is ablative laser resurfacing.
- Use of any laser or flashlamp (intense pulsed light) for hair removal poses a severe risk of eye injury when used near the eye. Other risks include fires, inhalation of the vaporized tissue plume, electrocution, and a host of side effects such as stimulation of facial hair growth, pigmentary changes, and scarring.
Laser emits radiation whose properties are fundamentally different compared to radiation of other sources. Laser radiation is monochromatic in a range from 100 nm to 3 mm, appears as strictly parallel beam, can be either continuous or pulsed in a range from seconds to femtoseconds (10−15 s), and can show intensities of more than 1010 W/cm2.
A few years after development of lasers in 1960, physicians such as Leon Goldman started to apply this new and exciting radiation in dermatology. Since 1963, numerous physicians have investigated the use of various types of lasers to treat different skin disorders. When laser radiation is absorbed in tissue, radiation energy is predominantly converted to heat. Because of its exceptional nature, laser radiation can be applied to cut, vaporize, coagulate, or ablate skin. It was identified as able to achieve selective destruction of targets inside skin. Laser pulses precisely destroy even very small targets in skin such as small vessels or melanosomes. By manipulating the appropriate laser parameters such as wavelength, pulse duration, and radiant exposure, the destruction of a target occurs without damage to the adjacent tissue, which substantially minimizes the risk of side effects like scarring. The selection of the appropriate laser parameters for an effective and precise destruction of targets in skin were summarized as the rules of selective photothermolysis.1
A newer light source appeared in dermatological practice some years ago: the intense pulsed light source (IPL).2,3 It mainly consists of a flashlamp that emits white light ranging from about 250–1,400 nm. The spectrum is narrowed (∼500–1,000 nm) by applying optical edge-filters ...