High intensity focused ultrasound (HIFU) works by generating high-frequency ultrasound through a transducer which focuses ultrasound energy onto a specific target area within the body, which is used in medical procedures to treat various conditions and diseases, e.g. treatment of cancer. HIFU is also used in cosmetic procedures where it is used for non-invasive dermatological sculpting and lifting of the dermis.
HIFU operates from a frequency range of 200 kHz to 7MHz, with energies exceeding 1,000 W/cm2. HIFU effectively eliminates fat cells while preserving the epidermis and dermis above and underlying tissues and organs by applying heat to induces focal coagulation and necrosis in fat cells.
The desired outcomes are achieved by heating the tissue to temperatures exceeding 60°C. This will encourage collagen contraction and the production of new collagen, resulting in tightened skin and reduced wrinkles, particularly around the face, eyes, neck, elbows, and knees.
Cavitation is another aspect of the destructive effect. Fat cells rupture due to rapid pressure changes, and the disintegrated fat cells are eliminated through metabolic processes HIFU has also been described as a method to reduce hyperpigmentation by decreasing melanin deposition in the epidermis.
The images below are examples of HIFU apparatus, applicator and cartridge commonly used in the medical aesthetic industry.
Risk and adverse health effects
The possible adverse health effects of HIFU on the human body range from mild pain, erythema, and edema of skin lasting a few days to more prevalent and wide-ranging effects. These include pain after treatment, edema, bruising, pain during treatment, tingling, erythema, and skin burns.
Most reported adverse effects from HIFU procedures have been temporary and resolved in a week or so, but no documentation exists for long-term follow-up beyond 6 months.
More information on the regulatory requirements can be found in the Advisory on Sale, Distribution, Possession and Use of Non-Ionising Irradiating Apparatus controlled under Radiation Protection Act page on our website.
1. Intended human exposure to non-ionizing radiation for cosmetic purposes, Health Physics 118(5):562–579; 2020