In the past, the observation of hair follicles by laser hair removal can only understand the situation of hair follicles through histopathology. With VHF ultrasound, the dynamic changes of hair follicles after laser hair removal can be detected noninvasively.
With the development and improvement of ultrasonic instruments and imaging technology, the probe frequency reaches 50MHz. This kind of ultrasound is called VHF ultrasound. VHF ultrasound has the effect of ultrasonic amplification, which can be used for skin thickness measurement, skin ultrasound research and skin disease diagnosis.
In this study, five volunteers were selected for leg depilation with 755nm laser, with energy of 22j / cm2 and pulse width of 40ms. They were observed by 50MHz VHF ultrasound every 1-2 months for 6 months. The hair follicles in the vertical section of the skin can be seen through B-ultrasound. After 755nm laser treatment, the hair follicles become smaller in the middle stage of treatment and disappear in the later stage. At the same time, B-ultrasound found that after laser treatment, the echo brightness of skin and dermis increased, the density of collagen fibers increased, and laser has the function of rejuvenating skin.
Through the clinical observation of laser hair removal by VHF ultrasound, it is confirmed that laser hair removal is safe and effective. As a non-invasive and rapid examination method, VHF ultrasound will have a broad application prospect in the diagnosis and treatment of skin diseases.
- Clinical photos before treatment showed dense and long hair
In the B-ultrasound photos before treatment, the minimum diameter of hair follicle in the middle layer of dermis is is 0.38mm, the maximum diameter of hair follicle is 0.73mm, and the echo brightness of dermis is dark
- After 3 months and 2 times of treatment, the hair follicle gradually became smaller, the minimum diameter of hair follicle was 0.38mm, the maximum diameter of hair follicle was 0.46mm, and the echo brightness of dermis was bright.
- Clinical photos after 4 treatments in 6 months
After 6 months and 4 times of treatment, the hair disappeared and the skin became smooth and tender. B-ultrasound found that the hair follicle gradually disappeared with a minimum diameter of 0.2mm. After laser treatment, the echo brightness of skin and dermis increased and the density of collagen fibers increased! (755nm alexandrite laser and 1064nm Nd: YAG laser) are integrated into one. Different wavelengths are selected for treatment according to skin and hair types. Dark skin and suntanned skin do not have to worry about side effects during treatment. Such a laser workstation with two high-power laser systems is equipped with a cooling fan for treatment, which provides cooling throughout the treatment, increases comfort, and can adjust the light spot at the same time.