As seen in Fig. 4.6, a higher blood and epidermal melanin absorption is in the 400-700 nm range, with a drop in the 700-900 nm range (deeper melanin selective wavelengths), and then an increase in blood absorption in the 900-1,200 nm range. This means that by using the 400-600 nm range, we can create a spectrum that will effectively treat vascular and epidermal pigmented lesions The longer spectrum (700-1,200 nm) will be helpful in targeting deeper vascular lesions and epdirmal pigments. The utilization of this bimodal filtration allows a system to utilize the wavelengths that it needs, while blocking out the wavelengths in the middle of its band, which simply adds unwanted heat in the skin. Palomar Medical Technologies, Inc.’s Starlux Lux G hand piece was designed to take
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Figure 4.6 Chart demonstrating Palomar’s patented double cutoff light filter for the optimization of spectrum relative to oxyhemoglobin absorption. |
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Before After Figure 4.7 Benign epidermal pigmentation treated with the Palomar Lux G hand piece. Photos courtesy of Haneef Alibhai, MD. |
advantage of the optimal peaks of absorption in oxyhemoglobin, which also correspond to high absorption in epidermal pigment.
Most pulsed light Fig. 4.7 systems use a type of slide-in filters that are not extremely precise in their wavelength cutoff. This type of filter is called a “reflective filter” which uses dichroic coatings on the slide in filter glass. Dichroic filters are angle dependent and wavelength dependent filters, which means that light bounces off the coating at various angles. These types of filters are very accurate when used with lasers, because lasers are monochromatic, but these types of filters are less accurate when used with pulsed light systems, because by definition they are multi-wavelength light sources. Therefore, all pulsed light systems that employ slide in filters must use this technology. Palomar’s unique, patented dual wavelength filtration system uses both dichroic filters and absorption filters. The dual filtration system provides a more precise specification on the short wavelength end of the spectrum and permits Palomar to produce the unique wavelength outputs of the Lux G and Lux V hand pieces. By definition, if a filter absorbs light to select a wavelength range, the light is converted to heat and the filter must be cooled. Therefore, slide-in reflective filters, such as those used by Sciton and Lumenis are not cooled, and thus can not be absorption filters.