#Piezo wave therapy skin

One advantage of HIFU surgery is that there is theoretically no limitation in selecting the location and the size of treatment region by determining the aperture size, focal depth, and operating frequency of a HIFU transducer.

#Piezo wave therapy skin

For this, a HIFU transducer should provide a small focal volume (e.g., 1 mm 3) placed at a shallow depth (i.e., 3вЂ“4.5 mm from the skin surface). For the skin treatment, high-intensity ultrasound (i.e., a source power of 0.45 to 7.6 J, ) should be delivered into either the dermis or the superficial muscular aponeurotic system (SMAS) to induce coagulative necrosis only in these layers without damage to the surrounding tissue and superficial layers. High-intensity focused ultrasound (HIFU) has drawn many attentions as an alternative tool for skin treatment such as skin tightening. This causes lowering therapeutic efficacy that leads to inconsistent clinical results and multiple treatments. This is mainly due to a limited penetration depth of light energy, so that a wavelength longer than an optimal one is generally used to increase penetration depth. However, the optimal wavelength is hardly used because the light energy with the wavelength rarely reaches a target in many cases. Note that an optimal wavelength is determined when a target highly absorbs the incident light energy with the wavelength. Since the light absorption in a specific target relies on its wavelength, an optimal wavelength should be selected in order to achieve high treatment efficacy. These methods are based on the absorption of incident light energy in a target. For this, photothermal therapy and photodynamic therapy (PDT) are currently available. Light energy is prevalently used in beauty treatment for skin and surgery for cancers, such as melanoma.

Based on the results, we concluded that the proposed double-focusing method is suitable to decrease F-number while maintaining a large aperture size.

The experimental results demonstrated that the fabricated double-focused transducer had a focal length of 10.2 mm reduced from an initial focal length of 15.2 mm and, thus, the F-number changed from 1.52 to 1.02.

In accordance with the proposed method, we designed and fabricated a 7-MHz double-focused ultrasound transducer. To meet the requirements, this paper, therefore, proposes a double-focusing technique, in which the aperture of an ultrasound transducer is spherically shaped for initial focusing and an acoustic lens is used to finally focus ultrasound on a target depth of treatment it is possible to achieve the F-number of unity or less while keeping the aperture of a transducer as large as possible. However, satisfying both conditions at the same time is demanding. For this, it is desirable to make the F-number as small as possible under the largest possible aperture in order to generate ultrasound energy high enough to induce tissue coagulation in such a small focal volume. Beauty treatment for skin requires a high-intensity focused ultrasound (HIFU) transducer to generate coagulative necrosis in a small focal volume (e.g., 1 mm 3) placed at a shallow depth (3вЂ“4.5 mm from the skin surface).