The Q-switched Nd:YAG laser (QSNd:YL) emits two wavelengths, 532 and 1064 nm, with a pulse duration of 5-10 ns, delivered through a mirrored, articulated arm. Current models have spot sizes of 2-8 mm and can operate at up to 10 Hz.
The long QSNd:YL 1064-nm wavelength has the least absorption by melanin and the deepest penetration. It is therefore potentially effective for both epidermal and dermal pigmented lesions. Use of a frequency-doubling crystal allows emission of a 532-nm wavelength (green). This wavelength is well absorbed by both melanin and hemoglobin. Because of the superficial penetration, this 532-nm laser is limited to treating epidermal pigmented lesions.
Epidermal lesions such as lentigines or ephelides treated with the QSNd:YL respond as well to treatment as they do after QSRL treatment. Cafe-au-lait macules, nevus spilus, and Becker's nevus do not respond as well to QSNd:YL treatment. The Q-switched 1064-nm laser is highly effective for removing deep dermal pigment such as nevus of Ota and Ito. Because this wavelength is less absorbed by melanin, higher energy is required than with the QSRL. Newly available Q-switched Nd:YAG lasers which generate high fluences at large spot sizes, have optimized treatment results. In an effort to treat tattoos without interference of melanin absorption, the 1064-nm Q- switched
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