Shedding Light on Lasers: Intense pulsed light: Understand your IPL system; get the most from your equipment

Key Points

Useful - if used properly

In my opinion, yes, an intense pulsed light device can be the most useful piece of equipment in your office, but only when used properly.

IPLs are not true lasers, solely because they do not fulfill the three criteria that define a laser. IPLs use a flash lamp to emit noncoherent, nonmonochromatic light. But the fact that IPLs do not fulfill the laser criteria does not make them any less valuable than their counterparts.

When IPLs where first introduced in the mid '90s, little was understood about exactly how to use them. Since the first IPL, much has changed. Most IPL systems today emit light with a range of wavelengths, anywhere from 500 nm to 1,200 nm. With this range of wavelengths, water, melanin and hemoglobin all act as possible chromophores in the skin.

This is an advantage in the sense that you can treat many conditions with the same device, and many times even in the same treatment session.

However, without understanding how to tailor treatments for the desired target chromophore, you may end up not treating any of them.

Wavelength

The range of wavelengths will depend on the system and on which handpiece or filter you use. There are two types of filters: cut-off and cut-on.

Cut-off filters are the most common and block all wavelengths below that filter number. For example, a 560 nm filter would allow all wavelengths above 560 nm and less than 1,200 nm to be emitted.

Cut-on filters block all wavelengths except for a small range right around the filter number. For example, a 1,064 nm filter might emit light from 1,060 nm to 1,066 nm.

Note that these are still not lasers, as they are not mono- chromatic or coherent.

Choosing the right filter is one important parameter in a successful treatment. When thinking about which wavelengths to use, you must consider both the condition being treated and the patient's skin color.

Since the highest absorption of melanin is at lower wavelengths, higher-wavelength filters - which are less absorbed by melanin - offer protection for darker skin types.

Higher-wavelength filters may also be used for better penetration when doing procedures such as hair removal, when penetration to the dividing cells is crucial for permanent removal. Lower-wavelength filters offer more absorption by melanin and are safe to use on lighter skin types.

Adjust for skin type

The darker the lesion, the easier it is to remove, even with longer wavelengths. When treating lighter lesions, you may need to adjust to a more pigment-absorbing, shorter wavelength. The lower limit will be determined by the patient's skin type.

In addition to filters, IPL systems can also be adjusted, just as lasers are adjusted, using fluence and pulse widths. The pulse width adjustment parameters and the number of pulses in a row are two of the variables that set IPLs apart from other laser and light systems.

Thousands of pulse sequence variations can be formed by adjusting number of pulses, pulse width and the delay between each pulse. This is one thing that makes IPL systems so user-dependent. One operator may obtain great results using a system, while another may have no success.