▶ Previous Artlcle: #14-11. Long-pulsed Nd:YAG Laser
Characteristics of Long-pulsed Alexandrite Laser
Following the previous issue covering the Long-pulsed Nd:YAG Laser, this issue will deal with the Long-pulsed Alexandrite Laser.
Chromophores for 755nm Alexandrite Laser are melanin, deoxyhemoglobin, and oxyhemoglobin (Figure 1).
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The comparison of absorption coefficients between melanin and oxyhemoglobin according to wavelength range (532nm, 1064nm, and 755nm) finds that the melanin absorption coefficient at 532nm is 555, 2.4 times higher than the oxyhemoglobin absorption coefficient of 235; the melanin absorption coefficient at 1064nm is 50, 16 times higher than the oxyhemoglobin absorption coefficient of 3.2; and the melanin absorption coefficient at 755nm is 163, 54 times higher than the oxyhemoglobin absorption coefficient of 3.
The melanin absorption coefficient at 755nm is markedly high compared to other two wavelengths, and therefore, selectivity for melanin at this wavelength is relatively high.
Therefore, if vascular and pigment lesions are present concurrently, the therapeutic effects on pigment lesions are inevitably high (Table 1).
Figure 1. Absorption coefficients of melanin, hemoglobin.
-To be continued
