SO YOU THINK YOU KNOW YOUR HIFU?
EVER WONDERED WHY YOUR HIFU DOESN’T GET THE RESULTS YOUR WANT? EVER WONDERED WHY YOUR CLIENTS END UP LOOKING MORE GAUNT AFTER TREATMENT? EVER WONDERED WHY SOME HIFU’S RETAIL IN EXCESS OF £8,000 YET YOU CAN PURCHASE OTHERS FOR UNDER £3,000? IS THERE REALLY A DIFFERENCE? THE ANSWER IS YES!
READ THIS ARTICLE ON HI INTENSITY FOCUSED ULTRASOUND SO THAT YOUR CLIENTS GET AMAZING RESULTS, FIRST TIME, EVERYTIME – AS IT WAS INTENDED.
WHAT IS HIFU?
Hi Intensity Focused Ultrasound is a is a non-invasive therapeutic, thermal technique that uses non-ionizing ultrasonic sound waves to heat tissue. HIFU can be used to increase the blood flow or lymph to organs through ablation, cavitation, thermal coagulation or implosion and it can be focused to destroy tissue, such as tumors or cataracts in patients.
The technology which is similar to ultrasonic imaging, uses ultrasonic waves – although in the case of HIfu – at lower continuous frequencies, to achieve the necessary thermal doses. However, pulsed waves may also be used if mechanical rather than thermal damage is desired. Acoustic lenses, transducers or phased arrays are often used to achieve the necessary intensity at the target tissue without damaging the surrounding tissue.
HIFU, although relatively new to the cosmetic arena, was first discovered back in the early 1940s with extensive important early work performed in the 1950s and 1960s on its efficacy. However until recently, clinical trials of HIFU for ablation were few (although significant work in hyperthermia was performed with ultrasonic heating), until recent advances in ultrasound technology arose, which has ultimately led to further trials on the ablation of tumors in the NHS and medical arenas.
Since the early 2000’s HIFU has been investigated for its benefits in cosmetics, namely to reduce vaginal laxity and to aid both face and body skin tightening. As clinical trials are few and far between, the safety and effectiveness of these devices and techniques have previously been disputed however in 2018, the NHS recognised HIFU as an effective method for vaginal tightening and moreover, a beneficial option for the treatment of incontinence.
At present, HIFU is not available on the NHS for cosmetic purposes, for vaginal rejuvenation or incontinence correction, however clinical trials are currently underway.
HOW DOES HIFU WORK?
HIFU transmits energy in the form of acoustic (sound) waves into specific targeted area, deep within the tissue, without causing any damage to surrounding cells. The energy is absorbed by the tissue creating heat, causing the temperature to rise to between 65-85 degrees which consequently destroys the cells through a process called coagulative necrosis. Higher temperatures are avoided to prevent the boiling of liquids inside the tissue. Coagulative necrosis is a form of cell death whereby specific trauma causes hypoxia (a lack of oxygen) and important nutrients reaching the cell which preludes in its death. Owing to the nature of the necrosis, the dead tissue is preserved for up to 7-days as the injury is believed to denature structural proteins as well as lysosomal enzymes thus blocking the proteolysis (digestion) of damaged cells. The lack of lysosomal enzymes allows it to maintain the coagulated morphology for some time which increases the likelihood of cell regeneration. In necrosis, if enough viable cell framework is present around the affected area, regeneration will occur. This is especially important in the formation of collagen and elastin within skin tissue as HIFU has the ability to produce 1000X more collagen, than microneedling alone.
Each sonication (individual ultrasound energy deposition) treats a precisely defined portion of the targeted tissue, thus multiple sonications are used to create volume of treated tissue. The extent of tissue damage occurs as a function of both the exact temperature to which the tissue is heated and the duration of exposure – this is called the ‘thermal dose’.
At high enough acoustic intensities, cavitation can occur. Cavitation is where microbubbles are formed around the ultrasonic field which oscillate, grow and then eventually implode (internal transient cavitation). This destroys fat cells by creating shock waves which mechanically alter the surrounding tissue. Cavitation can be unpredictable which is why it has been previously avoided in clinical applications however new technology has managed to control the delivery of heat thus lowering the temperature at which cavitation occurs.
THE MECHANICS EXPLAINED
The successful delivery of HIFU is subject to a number of variables namely distance, focus, intensity, resistance and absorption. The delivery of HIFU for cosmetic usage is focused through transducers which are curved to focus the waves at specific points. The power or intensity (joules) applied relates to the force at which the energy is delivered. The temperature achieved is proportional to the intensity applied and the area over which the ultrasound beam is spread – IE increasing energy and decreasing the beam width will create a rapid temperature rise at the focus point.
HIFU machines are manufactured specifically to reduce resistance, maximise focus, offer variable intensity and thus temperature absorption as well as deliver set depths, to achieve maximum rejuvenation effects. During production, the machines are developed to maximise the energy output, allowing temperatures to achieve the desired 65 degree benchmark through the distribution of waves. This is achieved by the degree of curve in the transducer as well as the internal power mechanisms of the machine. The machine is then set at various energy outputs against ideal parameters. Failure to match the correct parameters leads to insufficient energy production, an increase in resistance and a reduction in temperature, resulting in little to no treatment effect. HIFU machines post-production are tested to ensure they are calibrated to attain the desired outcome at each focal point. Without this testing, temperatures in excess of 85 degrees can be obtained, thus triggering cell implosion or internal cavitation resulting in non-regenerative cell death. This leads to a reduction in collagen and elastin and can destroy fat pads underneath the SMAS and dermal layers leading to ‘hollowing’ of the facial regions. It is for this reason why Medically Graded equipment is both more reliable and more effective as more stringent testing, manufacturing regulation and accuracy is applied.
Owning a medically graded HIFU is only part of the process, understanding the basic principles of energy distribution and wave focus is absolute key to achieving the desired results. HIFU is a variable energy which can be manipulated by the professional to attain different outcomes, therefore without a wide and coherent understanding of the mechanics of HIFU, unwanted reactions will inevitably occur.