High-Frequency (20 MHz) Focused Ultrasound: A Novel Method for Noninvasive Tattoo Removal.

Alternatives or complements to laser tattoo removal are needed. Laser removal requires 8-12 sessions and can easily take longer than a year. Some colors cannot be removed, and scars may appear. Applied to allergic reactions in red tattoos, lasers can boost the allergy. A recently developed 20 MHz high-intensity focused ultrasound (HIFU) is introduced as a complementary method to lasers, but also as a stand-alone treatment for selected groups. 20 MHz HIFU allows for application of high-power ultrasound energy to very small focal targets in the dermis, and thereby precise confinement of thermal lesions in the outer layers of human skin, precisely where tattoo inks are deposited. HIFU treatment is "color blind" and can target any type of colored pigment in the dermis. It produces a controlled thermal lesion (up to 65°C) with superficial necrosis followed by an eschar with embedded tattoo pigment. This eschar, containing the tattoo pigment, is discharged over some weeks, and finally replaced by healed skin. HIFU can efficiently remove tattoos of any color in only 1-3 sessions. It can be applied to tattoos when lasers fail to produce efficient removal. The types of side effects are the same as with lasers. The operator shall be trained and knowledgeable. 20 MHz HIFU can furthermore be used in clinical and esthetic dermatology for various other applications, and a range of applications are open in clinical dermatology.