Download History of Acoustic Acoustics, the science of sound, starts as far back

1. History of Acoustic
Acoustics, the science of sound, starts as far back as Pythagoras in the 6th century BC, who
wrote on the mathematical properties of stringed instruments and represented the harmonic
overtone series on a string.
Pythagoras (570-490 BC)
Aristotle (384-322 BC)
Aristotle understood that sound consists of contraction and expansion of the air and gave the best
expression of the nature of the wave motion. In the 16-17th centuries, Aristotle’s approach was
theoretically developed by Galileo Galilei and Marin Mersenne. Newton (1642–1727) gave the
physical understanding of acoustical processes by experimental measurements of the speed of
sound and the theoretical formulization of a relationship for wave velocity in solids.
In the 18-19th centuries, the application of new techniques of calculus and new approaches in
mathematics made the major contribution in acoustic theory. The major figures of mathematical
acoustics were Helmholtz in Germany, who developed the field of physiological acoustics, and
Lord Rayleigh in England, who described his theoretical approach in his main work, The Theory
of Sound (1877). Also, Wheatstone, Ohm, and Henry showed the physical analogy between
electricity and acoustics.
In 1880, brothers, Jacques and Pierre Curie discovered the piezoelectric acoustic effect. They
found that pressure of an alternate current polarizes certain non-conducting crystals (ex. quartz).
These crystals contract and expand at the same frequency at which the current changes polarity.
The sound field generated by these crystals, in turn, makes the molecules vibrate and oscillate in
the sound field to produce an ultrasound effect. The modern ultrasound equipment use a widelyknown synthetic crystal called a plumbium zirconium titanate (PZT) crystal. The
piezoelectricity (from the Greek word meaning “to press”) was an important scientific discovery.
In 1893, Sir Francis Galton constructed a whistle that produced ultrasound. The first
technological application of ultrasound was an attempt to detect icebergs by Paul Langevin in
1917. Paul Langevin, a student of Pierre Curie's, found that inverse piezoelectricity causes
piezoelectric quartz in alternating fields to emit high-frequency sound waves. This led to the use
of quartz in a variety of applications including the first practical transducer (an electronic device
that converts energy from one form to another) for ultrasonic pulse-echo detection, which was
used to detect submarines and explore the ocean's floor.
Ultrasound is used in many different fields. Ultrasound devices operate with frequencies from 20
kilohertz up to several gigahertzes, and detect objects and measure distances. Ultrasonic imaging
(sonography) is used in human and veterinary medicine. Also, ultrasound is used to detect
invisible flaws in non-destructive testing of products and structures. Industrially, ultrasound is
used for cleaning and mixing, and for accelerating chemical processes.
Application of ultrasound to produce an effect on human tissue must range from 0.7 to 5.0 MHz
2. Sound
What is sound? Sound is a form of energy, just like electricity and light. Sound is made when air
molecules vibrate and move in a pattern called waves, or sound waves. Sound waves are caused
by the vibration of objects and radiate outward from their source in all directions. The vibrating
object compresses the surrounding air molecules (squeezing them closer together) and then
rarefies them (pulling them further apart). This vibration produces fluctuations in air pressure
that travels outward from the object. When these changes in air pressure vibrate your eardrum,
nerve signals are sent to your brain and are interpreted as sound.
Also, mechanical vibrations perceived as sound travel through all forms of matter: gases,
liquids, solids, and plasmas. Solids and liquids consist of molecules that are held together by
elastic forces, which behave like rubber bands connecting each molecule to each of its nearest
neighbors. If one molecule is set in vibration, then it will cause its immediate neighbors to
vibrate, and in turn their neighbors, and so on until the vibration has propagated throughout the
entire material. This sound wave or sound energy is transmitted from one molecule to the next.
A sound wave cannot travel by itself. It needs a medium for transmission (solid, liquid, gas).
The matter that supports the sound is called the medium.
The word "acoustic" is derived from the Greek, word ἀκουστικός (akoustikos), meaning "of or
for hearing, ready to hear." The Latin term “sonic” used to be a synonym for acoustics and later
became a branch of acoustics.
Frequencies above and below the audible range are called "ultrasonic" and "infrasonic,"
respectively.
As shown in the image above, the audible frequency range for humans is typically between about
20 Hz and 20,000 Hz (20 kHz). Ultrasound is, therefore, not separated from "normal" (audible)
sound based on differences in physical properties, the only difference is that humans cannot hear
it. Although the upper frequency limit of the audible range varies from person to person, it is
approximately 20 kilohertz (20,000 hertz) in healthy, young adults. This limit in humans is due
to limitations of the middle ear, which acts as a low-pass filter. Ultrasonic hearing can occur if
ultrasound is fed directly into the skull bone and reaches the cochlea through bone conduction
without passing through the middle ear. Children can hear some high-pitched sounds that older
adults cannot hear, because the upper limit pitch of hearing tends to become lower with age.
Many animals, such as dogs, cats, dolphins, bats, and mice have an upper frequency limit that is
higher than that of the human ear and, thus, can hear ultrasound.
Bats use ultrasounds to navigate in the darkness.
Bats use a variety of ultrasonic ranging (echolocation) techniques to detect their prey. They can
detect frequencies beyond 100 kHz.
Many insects have good ultrasonic hearing and most of these are nocturnal insects listening for
echolocating bats. This includes many groups of moths, beetles, and praying mantis. Upon
hearing a bat, the insects will make evasive maneuvers to escape being caught by the bat.
Dogs can hear sound at higher frequencies than humans. For example, many dog whistles emit
sound in the upper audible range of humans, but some, such as the silent whistle, emit ultrasound
at a frequency in the range 18–22 kHz.
Whales and dolphins can hear ultrasound and use ultrasonic sounds in their navigational system
(biosonar) to orient and capture prey. Porpoises have the highest known upper hearing limit, at
around 160 kHz.
3. Physics of Sound and Ultrasound Waves
The simplest kind of sound wave is a sine wave. According to Wikipedia: “The sine wave or
sinusoid is a mathematical curve, which describes a smooth repetitive oscillation.” The sine
wave is important in physics because it retains its wave shape when added to another sine wave
of the same frequency. Generally, the shape of the acoustic wave is much more complicated than
the sine wave. The diagram below is used to show the simplest model of a wave to explain
physical characteristics.
Wavelength (ƛ)
One oscillation
(Frequency is number of oscillations per second)
The most important characteristics of sine acoustic waves are: frequency, wavelength, amplitude
and speed.
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Frequency is measured in number of cycles or waves passing every second. It is measured in
units called hertz (Hz). Frequency is usually denoted in literature by a Latin letter f or by the
Greek letter ν [nu].
Wavelength is a distance between two nearest peaks or two nearest troughs. It is measured in
meters (m). Wavelength is usually denoted by the Greek letter λ [lambda].
Amplitude is the wave’s height. It is the distance from the midline of a wave to the top of a
crest or to the bottom of a trough.
Wave speed (denoted as c), wavelength λ and frequency ν of the sine wave are related in the
following equation:
c (m/s) = λ (m) · ν (Hz)
Wave is an energy transport phenomenon when wave transports energy along a medium without
transporting matter. The amount of energy E (denoted as J) carried by a wave is related to the
amplitude A of the wave. A high-energy wave is characterized by high amplitude; a low-energy
wave is characterized by low amplitude. The energy transported by a wave is directly
proportional to the power P (denoted as W) or square of the amplitude of the wave.
E(J)
P(W) = A2 (
means proportional).
Energy contained within a wave is decreased as it travels through the matter (in this case, tissue).
Different things can happen. The wave energy could be absorbed, reflected or transmitted by the
tissue.
The possibility of a sound wave to pass with various speeds through the tissue (medium) depends
on the closeness of molecules that determines density of the medium. Closely-located molecules
very quickly collide with each other and, thus, lose all energy of the incident wave in a short
distance in the tissue depth. The energy of wave is absorbed and we do not hear a sound. For
example, the sound quickly absorbs in the brick wall due to its high atomic density, while the
sound very quickly propagates in the air because molecules of air are located far apart from each
other.
As a result of absorption of energy, heat is formed. The electrons of atoms have a natural
frequency at which they tend to vibrate. When a wave impinges upon an atom, the electrons will
absorb the energy of the wave and transform it into vibration motion. During its vibration, the
electrons interact with neighboring atoms to produce friction and convert its vibration energy
into thermal energy. The reflection of sound follows the law "angle of incidence equals angle of
reflection," sometimes called the law of reflection. The reflected waves can interfere with
incident waves, producing patterns of constructive and destructive interference. This can lead to
resonances called standing waves. It also means that the sound intensity near a hard surface is
enhanced because the reflected wave adds to the incident wave, giving pressure amplitude that is
twice as great in a thin "pressure zone" near the surface.
4. Ultrasound and Human Tissue
Ultrasound is widely used for diagnostics to visualize a condition of internal organs of the
person, especially in an abdominal cavity and a pelvic cavity. Ultrasound is safe and simple in
comparison with X-rays and magnetic and resonant tomography. Ultrasound energy is nonionizing radiation and, therefore, its use does not impose the hazards, such as cancer production
and chromosome breakage attributed to ionizing radiation. Ultrasound’s ability to break off
membranes of biological cells is very popular (i.e., if necessary, to separate a cell from enzymes
or destroy fatty cells.) Besides its wide use in diagnostic purposes, ultrasound is applied in
medicine as a remedy. Ultrasound acts as an anti-inflammatory, resorbable, analgesic,
antispasmodic, cavitation strengthening of permeability of skin.
increase the healing effect.
It can decrease pain and
The mechanical, heating and cavitation effects are the main effects of ultrasound in human
tissue. The detailed explanation is shown below.
4.1
Mechanical Effect
Ultrasonic short waves penetrate into the skin, causing vibration of human cells and
generating a gentle massage. The periodic changes of a cell’s volume increase the blood
and lymph circulation.
One of the results of the mechanical effect is pain control. Vibration can help reduce some
types of pain. When ultrasound is applied to painful areas, pain signals have been
prevented from traveling to the central nervous system by inhibiting conductivity of nerve
impulses.
A combination of mechanical, heating and healing powers of ultrasound not only reduces
pain, but also helps muscles to be stretched and strengthened. Ultrasound causes tiny
vibrations (microvibration) in the cells of the soft tissue. This mechanical effect prevents
the formation of scarring of the tissue and in some instances, can break down alreadyformed keloids.
An intense ultrasonic field improves and increases tone of the skin tissue. It can promote
stimulation of biological active agents, decreases spasms in muscles, reduces wrinkles,
and helps to eliminate the serum from clogged pores by emulsifying them.
4.2
Warming Effect
Heat or a warming effect is the one of the main effects that is produced by ultrasound. It
plays an important role in physical therapy. The action of ultrasound in human skin tissue
cells and water molecules produces intensive fluctuation and friction on them. The result
of these actions is heat production. It can increase temperature of skin tissues as deep as 23 mm. Generated heat stimulates the body’s circulatory system and skin cell activity. It
also increases the function of metabolic rate and nutrient intake. Heat stimulating the
nervous system also minimizes pain sensation, and softens and decreases tissue tension in
the body.
4.3
Deep Heat
As was explained before, the heat generated by vibration of sound waves has the ability to
appear all the way down to the molecular level. This is a benefit of ultrasound over a
traditional hot pack, which cannot penetrate into deeper muscular or joint tissues.
Ultrasound heads can target a variety of depths according to different frequencies (the
longer the wavelength, the deeper it can penetrate). That gives a skilled therapist the
ability to send heat exactly where she or he wants it to go. Some conditions that may
benefit from this deeper heat include osteoarthritis and phantom limb pain.
Other benefits of ultrasonic deep heat stimulation are increased speed of the healing
process and relaxed tension of muscle spasms. Generated by ultrasound, the deep heat can
accelerate metabolism of tissue cells by the increased blood flow. Tissue cells get more
receptive to body chemicals responsible for the healing.
Because of this, ultrasound’s healing benefits may be useful in treating surgical wounds
and soft tissue lesions. Also, the deep heat can help relax a tense or strained muscle. This
can help minimize muscle spasms often associated with tension or injury. Studies indicate
that ultrasound therapy has the added benefit of increasing range of motion.
4.4
Cavitation
The main effect of ultrasound on the human body is cavitation.
What is cavitation?
Cavitation (from Latin- cavitas emptiness) is a process of formation of cavities or void
(cavitation bubbles) in liquid, sometimes filled with gas, steam or their mix. However,
later research showed that the gases, which are found inside of created bubbles, play an
important role in formation of a cavitational effect. The liquid always contains these
gases, and when the local pressure decreases, those gases start to move intensely inside
the specified bubbles.
The cavitation bubble can move from an area with low pressure to an area with high
pressure, thus changing the sizes. It can pass some periods of increase and decrease.
Moving with a stream to an area with higher pressure, the cavitation bubble can be
broken off and, thus, emits a large amount of the energy capable of influencing any
matter.
For example, this energy easily breaks a membrane of a fatty cell which releases fat
substances into intercellular space. Oscillating bubbles make vigorous circulating
movements in this area and make a "diluting" or liquefying effect in the fat substance.
The effect of emulsification is very important for the lymphatic system, which has to
eliminate fatty substances from the body.
As mentioned before, heat is a result of absorption of a wave’s energy. Because the
cavitation bubbles can sharply contract and expand, gas temperature in bubbles fluctuate
over a wide range. In some spots, the temperature during cavitation can rise up to 5000oK
or 8540oF. It is necessary to also consider that the gases dissolved in liquid contain more
oxygen than in air. Thus, those gases in cavitation bubbles are chemically more
aggressive than atmospheric air. The result is an oxidizing reaction in substances.
Cavitation can be hydrodynamic and acoustic. Hydrodynamic cavitation results from
decreasing pressure in liquid. This change can be caused by an increase in speed of its
movement (i.e., behind the propeller of vessels).
Acoustic cavitation arises when acoustic waves of high intensity pass through liquid. The
most noticeable principle of cavitation can be observed by boiling water or bottle stirring
with sunflower oil when hollow bubbles form in liquid and "cavitation circulation"
begins. These types of cavitation are used in esthetic medicine.
Cavitation is usually divided into two classes of behavior: inertial (or transient) cavitation
and non-inertial cavitation.
Inertial cavitation is the process of rapidly-collapsed bubbles that produce a shockwave.
According to Encyclopedia Britannica, a shock wave is a strong pressure wave in water or
other mediums produced by explosions of collapsed bubbles. The explosions of shock
waves create a violent change in pressure, density, and temperature. Because of this,
shock waves propagate in a manner different from that of ordinary acoustic waves. In
particular, shock waves travel faster than sound, and their speed increases as the
amplitude is raised; but the intensity of a shock wave also decreases faster than a sound
wave, because some of the energy of the shock wave is converted to heat at the medium in
which it travels. Inertial cavitation occurs in nature in the strikes of mantis shrimps and
pistol shrimps. In man-made objects, it can occur in control valves, pumps, propellers, and
impellers.
The non-inertial cavitation forms when the acoustic field stimulates small bubbles to
oscillate in a liquid. These bubbles do not collapse easily. This form of cavitation causes
significantly less erosion than inertial cavitation, and is often used for the cleaning of
delicate materials. Acoustic streaming, heat production, and radiation forces on
surrounding particles can be caused by the motion of the bubbles in non-inertial
cavitation.
4.5
General Cavitation Damage Effects
Significant damage of moving parts of different machines (turbines or propellers) could be
formed by cavitation. When the cavitation bubbles collapse, they force energetic liquid
into very small volumes. These movements create the spots of high temperature, emitting
shock waves and generating a source of noise. Also, collapse of a cavity can erode metals,
such as steel, to produce the pitting or chipping and great wear of components over time.
Concentrated energy of ultrasound in very small volumes can cause such phenomena, as a
rupture of chemical bonds of macromolecules, initiation of chemical reactions, an erosion
of surfaces of solid bodies and a luminescence. In industry, the principle of cavitation is
widely used to homogenize (mix) and break down suspended particles in a liquid.
The similar cavitation effects can be observed in biological objects and, in particular, can
be utilized for biomedical applications in the body.
5. Biomedical Application of Cavitation.
Detailed studying and medical tests of the ultrasound waves with a frequency of 35-45 KHZ in
the biological objects showed and confirmed the safety of the biomedical application of
cavitation.
The difference of pressure forms micro bubbles which violently blow up and destroy
surrounding solid bodies, including fatty deposits.
Also, in the field of medicine, cavitation is applied to removal of kidney stones (lithotripsy)
which are crushed by micro bubbles. Ultrasound is sometimes used to increase bone formation,
for instance post-surgical applications. It has been proven that cavitation can be used for
movement of big molecules into biological cells.
A detailed explanation of the cavitation process and possible results that can affect biological
cells follows.
The cavitation mechanism occurs when there is a pressure gradient over a bubble. These bubbles
are usually smaller than the acoustic wavelength of the ultrasound source. When two bubbles are
close to each other and a force is exerted on the first bubble, energy is scattered from the first
bubble and affects the second bubble. The scattered energy from that bubble also affects the first
bubble. This scattered acoustic wave may affect smaller particles, such as biological cells. The
result of the application of cavitation in the biological objects is heat generation, micro streaming
and shock waves.
5.1
Microstreaming
A vigorous circulatory motion of oscillating bubbles in a sound field produces micro
streaming. These oscillating bubbles can be pushed by an acoustic force of the traveling
wave. The fluid velocity is greatest near the bubble surface and can be changed with
respect to distance from the bubble surface (velocity decreases when distance from the
bubble increases) and creates the differences in forces or velocity gradient. This unequal
distribution of forces from the fluid onto the exterior of the cell results in shearing stresses
or forces that are likely to distort and tear the cell membrane. The exposure of a highstress field produces significant damage in a cell.
5.2
Shock Waves
As mentioned before, the shock waves are produced when a bubble is exposed to high
acoustic pressures in conjunction with higher amplitudes and oscillations in bubble
volume. The bubble contraction from minimum to maximum produces rapid changes in
pressure of surrounding fluid. This fluid gains momentum of pressure and bubbles are not
able to resist and rapidly collapse. The shock in the surrounding fluid will propagate
outward. If a biological cell or tissue is exposed to the shock wave, it will experience
much stress. This stress may be enough to damage exposed biological materials.
5.3
Heat
During cavitation, the ultrasound kinetic energy can also be converted into heat if it is
absorbed by tissue. When the cavitation bubbles grow to the critical size, they collapse
violently under the pressure, and these implosions produce large, local pressure and
temperature. During cavitation, generated temperature in tissue between 40 oC to 45oC has
the same physiological effects as heat generated by ultrasound.
6. Effects of Cavitation in the Aesthetic Field
Ultrasound Cavitation, also known as Liposuction Cavitation or Fat Cavitation, is a relatively
new aesthetic treatment of reshaping the body by eliminating fat cells under the skin.
Using leading-edge technology, it converts fat cells into fluid, which can then be naturally
drained by the body’s own natural filtration system.
The most important physiological effects of cavitation are:
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The effect of cavitation on fatty tissues leading to fragmented, emulsified and converted fat
into the blood lipids (triglycerides).
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Removal of emulsified fat by means of natural metabolic process.
The low-frequency ultrasonic waves pass through the skin and reach subdermis fatty tissue and
accumulate enough energy to destroy a membrane of a fat cell. There is a selective destruction of
fat without damage to other nearby tissues, such as small arteries, veins, or muscles.
Cavitation of fatty tissues happens under the influence of a certain frequency range (35-45
KHZ). With this frequency, the maximum quantity of bubbles of the optimum size is formed.
Increasing in size, they dilute fat and force it out from fat cells. A collapse of bubbles in fatty
tissue releases a large amount of energy in the form of micro explosion. This micro explosion
damages cellular membranes of the fat cells.
The most damage occurs where there is the greatest tension of fat cell membranes, especially for
the cells most filled with fat. The emulsified fat, under the action of heat and ultrasonic
cavitation, is converted to triglycerides. Triglycerides, known as blood lipid, usually derive from
glycerol (water-soluble substance) and three fatty acids.
The released triglycerides of the fat cells are removed from intercellular space by means of
natural metabolic processes. 90% of products of the emulsified fat are removed through the
lymphatic system and 10% are absorbed in the blood stream where released triglycerides will be
transformed to glucose molecules.
At the time of cavitation, other cells and tissues (muscular fibrilla, cells of epidermis, an
endothelial of vessels, etc.) are not damaged due to their strength and sufficient coefficient of
elasticity. Much scientific research proves efficiency and safety of cavitation procedures.
“Ultra- Focus” devices allow using cavitation and radiofrequency (RF) procedures in one
treatment. Destruction of fat and strengthening of the tissues are the main goals to satisfy all
clients’ demands. It also helps to eliminate lipomas (fatty bumps) that often occur after invasive
liposuction and make skin even and smooth. The influence of radio frequency accelerates the
process of regeneration, promotes removal of liquids and toxins, and eliminates symptoms of
cellulite. The tissue becomes more elastic and fresh without an effect of the "blown-off" flabby
skin.
Ultrasonic cavitation is becoming a leading method in the field of esthetic medicine for reduction
and destruction of the fatty deposits and cellulite.
The technology and devices used for ultrasonic cavitation are becoming very popular due to
availability, simplicity of use, and reasonable prices.
7. Contraindication to Ultrasonic Cavitation
Even though studies have proven the treatment safe, cavitation is not to be used on clients with
the following health issues:
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Compromised liver function, chronic diseases of the liver, HBV& HCV, and cirrhosis
Any type of cancer, including cancer treatments, history of chemo-radiotherapy (requires
MD release paper)
Active tuberculosis
Psoriasis
Epilepsy and convulsions
Decreased circulation
Infection/inflammation
Pregnancy
Central nervous system disorder
Implants (metal, plastic), pacemakers
Thrombophlebitis
Uncontrolled bleeding or blood-thinning medication (Aspirin, Coumadin)
When using cavitation in esthetic medicine, it is important to not only consider the location and
depth of cellulite and fatty deposits, but also the existence of anatomic formations which can be
incidentally affected by ultrasound of low frequency. On the basis of this data, a choice of the
power used during the procedure and frequency of the ultrasound device becomes very
important. These characteristics are important as well as an assessment of the equipment existing
in the market, different types of apparatus, the sizes and shapes of hand pieces, and so on.
Ultrasound energy is absorbed mostly in tissues with high collagen content (bone, cartilage,
ligaments, scar tissue). Ultrasound at high intensity near boney areas can be painful because of
high energy accumulation and a heating effect on the soft tissue as sound waves hit the bone.
This is why the technician must follow these recommendations:
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Avoid direct application on the anatomic formations such as eyes, kidneys, heart, sex organs
and endocrine gland locations.
Avoid exposure of ultrasound on bones where there is thin skin to reduce pain sensation.
Do not treat areas where there are insignificant amounts of fat layers.
Hold the hand piece perpendicular to the treated area
Do not hold the sound hand piece in one place.
Do not apply heavy pressure to the area of treatment.
8. Ultrasonic Cavitation for Body Sculpting
8.1
Chronology of the protocol of procedures:
1.
Fill out the medical history of the patient. Obtain general information, medical
questions list, and signature for informed consent.
Photo (if some lesions exist).
Measurement of a fatty layer by a tape (an anthropometrical method).
Putting ultrasonic gel on treated areas.
Use the “Ultra-Focus” cavitation machine no more than 20 minutes on each zone.
After cavitation treatment, use RF modality for eliminating a sagging effect (see
section 9). It also improves tone and toughness of the skin (20 minutes on each
zone).
Remove remaining ultrasonic gel and clean treated area with a paper towel or
gauze.
2.
3.
4.
5.
6.
7.
Additional Recommendations:
8.
9.
10.
It is recommended to use a lymphatic drainage machine at the end of the
procedure for acceleration of removal of disintegration products from treated area
(20 minutes on each zone).
A facial treatment such as a calming mask and nutrient creams, lifting facial
massage, or other facial treatments to significantly improve tone texture and
strengthen skin.
It is more effective if the cavitation is combined with Fractional Laser, and an IPL
skin tightening procedure.
The cavitation treatment does not require any special pretreatment. It starts with a circumference
measurement of the targeted body area, continues with circular movements of the applicator over
the treatment site, and ends with another circumference measurement (see section 8.3).
For better results of the patient, it is recommended to measure the treated area three times before
the first treatment, in the middle of the treatments, and at the end of the treatments.
In certain cases, the treatment can start with a short RF application (around 5 minutes) to “warm
up” the tissue that increases the effectiveness of cavitation.
The duration of the treatment can vary from 20 to 40 minutes, depending on the size of the area
and the thickness of the fat layer.
It is suggested that the time and intensity of the first and second cavitation treatments has to be
shorter (no longer than 20 minutes) and lower (power level at 4-5). That gives the client’s body
a chance to adopt emulsified fat and help the lymphatic and urine systems to eliminate the fat.
The duration of the following treatments can be longer than 30-40 minutes and in higher
intensity. For the same reason, the time between treatments has to be at least 5 to 7 days apart,
depending on the quantity and density of fat in the area. Six to twelve sessions are recommended
in order to achieve a notable result, but further treatments may be needed to attain desired results.
The new procedures package can start after 2 -3 months.
A fully-trained therapist will apply a specifically-designed hand piece to client’s skin. As
mentioned before, the hand piece will transmit low-level ultrasound waves which consist of
compression-expansion impulses that travel in high-speed cycles. This back and forth cycle then
causes an infinite quantity of micro-cavities or micro-bubbles that gradually enlarge. This
progressive enlargement finishes as micro-bubbles start to collide and implode, producing shock
waves that favor emulsification and elimination of fat tissues (the process of cavitation). The
cavitation causes the fat to emulsify, converting it into a substance that is then easily eliminated
out of the body through the lymphatic and urinary systems.
The treatment does not require anesthesia. Most clients consider the procedure painless and
comfortable. There may be, however, a slight discomfort due to the specific ringing noise
spreading inside the patient’s body, but it poses no harm and disappears as soon as the skin
breaks contact with the applicator. The patient may experience a little warmth during the
treatment. If during treatment the area begins to feel hot for the client, apply more ultrasound gel
to the site.
There is a slight possibility of mild side effects such as transient redness, excessive thirst,
frequent urination and nausea immediately after the treatment, which can be resolved by drinking
water. They are all short-term effects that disappear within a few hours.
The effects from cavitation are noticeable immediately after the first session. Research has
shown that it can reduce up to 15 cm3 of fat that corresponds to volume loss in the waist, and
from 3 to 5 cm after one session of cavitation. After removal of the disintegration products,
accumulation of fat in the processed area becomes extremely difficult. The patient loses both
volume and weight after the procedure. A large amount of fatty tissue has low density and is
lightweight, which is why all of the clients notice volume loss. It is necessary to recommend to
the client an active lifestyle and healthy nutrition and drinking habits. The results may vary with
different tissue structures, treatment areas, age, metabolism, medications, and changes in
hormones. Proper diet and increased physical activity will certainly improve and help to
maintain the results. All patients have to follow a low calorie diet and drink plenty of fluids of at
least 2L a day. Regular exercise such as walking or other aerobic/cardio activities for 25-30
minutes should also be strongly recommended to better process the fat elimination after
treatment. Areas where treatment is most effective are those that have localized fat - the thighs,
abdomen, and buttocks. However, there is no real limitation as to areas of the body.
Cavitation is not a method to lose weight but to reshape the body. It is particularly effective for
the reduction of fat deposits in the “estrogenic” area (“the love handles” and abdominal stubborn
areas that will not go away with diet and exercise). Ultrasound cavitation is similar to
liposuction in that it removes cellulite, thus preventing it from recurring in the treated areas
without damaging the vascular system.
8.2
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Benefits of an Ultrasonic Cavitation Treatment
Improved blood circulation and lymph circulation
Improved skin texture
Body tightening
Excellent performance of body shaping
Removal of fat cells permanently
Non-invasive, no pain
No anesthesia, no post-operative care
No down time
Cellulite therapy
Connective tissue tightening
Figure 1:
Figure 2:
Figure 3:
Figure 4:
8.3
Before treatment. Fat cells basic structure
5 minutes after beginning treatment, the image shows a decompression of
the fat tissue along with formation of small bubbles because of weakening
of the cellular membrane
10 minutes after the cavitation begins, the image shows destruction of fatty
membranes and considerable emulsification in places of processing
Distinctly shows full emulsification of a fatty layer
The schematic illustration of movements for Ultrasonic Cavitation treatment.
Common recommendations:
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Avoid direct application on the anatomic formations such as eyes, kidneys, heart, sex
organs and endocrine gland locations.
Avoid exposure of ultrasound on bones.
Do not treat areas where there are insignificant amounts of fat layers.
Do not apply heavy pressure to the area of treatment.
Do not hold the ultrasound hand piece in one place.
Hold the hand pieces perpendicular to the treated area.
Do not apply heavy pressure.
Movements in cavitation are very similar to circular “dough kneading” movements.
During cavitation, the circular movements of hand pieces must be clockwise in
abdominal area and counter clockwise in other areas which can help to eliminate
decompose fat (see Fig.1).
Fig.1 Schematic illustrations of movements for body in ultrasonic cavitation
treatment.

At the end of procedure use lymphatic technique.

During lymphatic technique, hand piece pressure has to be about two times less
than in cavitation movements. This technique can stimulate the lymphatic system
easily and quickly eliminate emulsified fat from the body (see Fig.2).
Fig.2 Schematic illustrations of movements for body in lymphatic technique treatment.
Abdomen area:



Begin your work with small circular, clockwise movements around belly button,
gradually increasing movement radius (see Fig.1).
Work on this area around 15 or 25 minutes, depending on treatment number.
At the end of procedure use lymphatic technique: The free hand pulls skin towards
the ribs. With straight-line movements, slowly pull down the hand piece towards the
groin area where lymph nodes are. Work on this area for the remaining 5 minutes
(Fig.2).



Back area:
Push hand piece up and down with small circular, counter clockwise movements on
the applied area (see Fig.1).
At the end of procedure use lymphatic technique: For upper back: The free hand
pulls skin towards the waist. With straight-line movements, slowly pull up hand piece
towards axilla (armpit) areas, where lymph nodes are (see Fig.2). For lower back and
buttocks: The free hand pulls skin towards the ribs. With straight-line movements,
slowly pull the hand piece towards the right and left buttocks side area where lymph
nodes are.
Work on these areas the remaining 5 minutes (see Fig.2).
Thighs areas:




Push hand piece right and left with small circular, counter clockwise movements on
the applied area (see Fig.1).
At the end of procedure use lymphatic technique:
The free hand pulls skin towards the knee. With straight-line movements, slowly pull
up the hand piece towards the groin or buttocks area where lymph nodes are.
Work on these areas the remaining 5 minutes (see Fig.2).
Arms area:



Push hand piece up and down from inside elbow to armpit with small circular,
counter clockwise movements on applied area (see Fig.1).
At the end of procedure use lymphatic technique: The free hand pulls skin towards
the elbow. With straight-line movements, slowly pull up hand piece towards axilla
(armpit) areas, where lymph nodes are.
Work on these areas the remaining 5 minutes (see Fig.2).
Face area: Double chin and jowls


Always push hand pieces from down to up and from the center of the face towards the
ears.
Using the schematic illustration below, work with small circular, clockwise
movements on left side of face and counter clockwise movements on the right side of
face (see Fig.3).
Fig.3 Schematic illustrations of movements for face in ultrasonic cavitation treatment.

At the end of procedure use lymphatic technique: The free hand pulls the skin
towards the ears. With a straight-line movement, slowly pull down hand piece
towards low jaw (mandible) and upper neck where lymph nodes are. All facial
lymphatic movements have to be from up to down and from the center of the face
towards the ears. Work on these areas the remaining 5 minutes (see Fig.4).
Fig.4 Schematic illustrations of movements for face in lymphatic technique treatment.
9. Radiofrequency
9.1 What are Radio Waves?
Radio waves are the electromagnetic radiation that travels in space with velocity of light
(300,000 km/s) and transfers the energy. These waves are generated by atoms of all chemical
elements. Electromagnetic radiation is transferred by means of photons. Photons are
uncharged particles which do not have weight, behave as waves, and carry the minimum
quantity of energy. Electromagnetic waves carry together the electric and magnetic fields
which have been initially generated by a certain atom in an exited state.
Similar to sound waves, the electromagnetic waves are also described by sine waves and
characterized by the frequency, wave length and power of transferable energy. The frequency
of electromagnetic waves shows how many times per second the value of electric and
magnetic fields changes in each point of space. Electromagnetic waves freely pass through
air or a space (vacuum) and they don’t require a medium like a sound wave does.
Above is an illustration that shows an electromagnetic spectrum of radiation. It is broken
down into smaller groups based upon their frequencies and wavelengths. They are
gamma, x-rays, ultraviolet, visible light, infrared, microwaves, and radio frequency. The
larger group of waves is radio waves or radiofrequency.
The radio waves can appear when alternating current, with frequency in the range
between 10 kHz and 300 MHz, passes through the conductor.
The radio waves are not ionizing radiation and can easily penetrate into biological tissues
without damaging the tissue’s structure. Quickly-fluctuating electromagnetic fields cause
movement of the polarized particles in tissue and water molecules. The result of these
actions (vibrations and friction) is heat production that is proportional to electric
resistance of these tissues.
This phenomenon became a breakthrough in esthetic medicine.
9.2
Radio Frequency and Heat in Esthetic Medicine.
Radiofrequency treatment is a thermal procedure which uses radio waves for restoration
of deep layers of tissues under the skin. It is a new trend in the non-surgical field of face
lifting and tightening of the skin.
Generated heat stimulates production of collagen in a zone of influence, improves micro
blood and lymph circulation, and reduces inflammation as well.
Deep and uniform heat causes partial compression of fibers of collagen, and makes them
more dense and compact. This process happens because of destruction of thermolabile
cross-bonds in collagen molecules that reduce residual tension between them. The
increase in temperature stimulates fibroblasts to synthesize new collagen and gives the
prolonged effect of deep reconstruction of tissues. Created heat increases density and
elasticity of skin and provides an effect of lifting.
Radiofrequency treatment is used for facial tightening of clients with mild to moderate
sagging of facial tissue.
The electromagnetic field created by radio frequency is capable of strengthening
movement and drainage of liquids in skin and fatty tissue. It renders a positive effect to
reduce puffiness and also promotes removal of toxins. This is why it is very important to
use radiofrequency in conjunction with ultrasonic cavitation to eliminate emulsified fat
and tighten the skin in the same area where the cavitation treatment has taken place.
The new type of ultrasonic device “Ultra-Focus” includes two distinct modalities,
ultrasonic cavitation and radiofrequency, which perfectly complement each other.
Tripolar (facial) and multi-polar (body) hand pieces deliver the current that flows only
through the tissue which is between the electrodes on the hand piece. The purpose of
these electrodes is to complete the electrical circuit. Hence, no current flows through the
rest of the body, so no grounding or return pad is needed. The hand piece transmits radio
waves through the upper layers of the skin to the dermis. The radiation heats up the deep
targeted area between 40 and 55 degrees Celsius and does not burn the skin’s surface.
The heat causes not only local contraction of the collagen fibers, but also stimulates new
collagen production. It also immediately tightens the skin, but sometimes a tightening
effect can be delayed from 3 to 6 months to be visible. Also, a high temperature reaches
a deep fatty layer and produces partial lipolysis or, in other words, melts fat.
As mentioned before, RF will also improve the blood and lymphatic flow. This helps
with a better oxygen supply and greater toxin clearance to further reduce the effects of
aging.
9.3












Contraindications to Radiofrequency Treatments:
Any skin diseases, inflammation or infections in the area being treated
Pregnancy
Pacemakers, dental and body metal implants
Thyroid gland disease
Cancer and cancer history (requires MD release paper)
Epilepsy
Umbilical hernia
Endometriosis
Varicose veins
Herpes in an active form
Skin sensitivity
Retin-A, Accutane (postpone for 6 months as it is highly possible it will produce
post-treatment hyperpigmentation on the treated area).
9.4
Pre- and Post-Treatment Considerations for RF Treatment:
It is very important for the technician to start the procedure with a detailed discussion
about the client’s medical conditions and medications. Each time they are treated, the
technician must update their medical information.
Before and after treatment, the client should avoid any irritation of skin including sun
exposure and any exfoliation procedures (microdermabrasion, acidic peels, etc.).
After treatment, mild redness and itching can appear that disappears after 30 minutes.
9.5
Chronology of the Protocol of Procedures for RF Treatment:
If RF is a continued procedure after Ultrasonic Cavitation:
1.
2.
3.
4.
Put additional amount of ultrasonic gel on treated areas.
Use “Ultra-Focus” appropriate RF hand piece no more than 20 minutes on each
zone.
Remove remaining ultrasonic gel and clean treated area with paper towel or
gauze.
Soothing gel or moisturizing lotion may be applied to the skin after treatment.
Use only “alcohol-free” gel.
If RF is a separate procedure:
1.
2.
3.
4.
5.
6.
7.
9.6
Fill in the medical history of the patient. Obtain general information, medical
questions list, and signature on informed consent.
Photo (if some lesions exist).
The client’s face or body should be washed with soap and warm water
prior to treatment in order to remove any makeup and oil.
Put ultrasonic gel on treated areas.
Use “Ultra-Focus” appropriate RF hand piece no more than 20 minutes on each
zone.
Remove remaining ultrasonic gel and clean treated area with paper towel or
gauze.
Soothing gel or moisturizing lotion may be applied to the skin after treatment.
Use only “alcohol-free” gel.
The Schematic Illustration of Movements for Radiofrequency Treatment.
Common recommendations:



Do not hold the RF hand piece in one place.
Do not apply heavy pressure to the area of treatment.
Movements in RF are very similar to painting a wall, with light, gliding movements.

During radiofrequency, the movement of the hand piece must be clockwise in the
abdominal area. In other body areas, all movements are straight, which can help to
tighten and lift the skin (see schematic illustrations shown below (Fig.5).
Fig.5 Schematic illustrations of movements for body in radiofrequency treatment.
Abdomen area:


Begin your work with circular movements clockwise around belly button, gradually
increasing movement radius. At the end of the procedure, all movement must follow
massage body lines shown in Fig.5, above.
Work on this area about 20 minutes.
Back area and buttocks:


Move hand piece up-down and right-left with light, straight movements on the
applied area. At the end of the procedure, all direction must follow massage body
lines shown in Fig.5.
Work on this area about 20 minutes.
Thighs areas:


Move hand piece up-down and right-left with light, straight movements on the
applied area. At the end of the procedure, all direction must follow massage body
lines shown in Fig.5.
Work on this area about 20 minutes.
Arms area:


Move hand piece up-down and right-left with light, straight movements on the
applied area. At the end of the procedure, all direction must follow massage body
lines shown in Fig.5.
Work on this area about 20 minutes.
Face area:

The facial lifting lines for RF movements are shown below in Fig.6.
Fig.6 Schematic illustrations of movements for face in radiofrequency treatment
ULTRASOUND CAVITATION AND RADIOFREQUENCY EXAM
1.
Ultrasonic is a range of sound frequencies that is _____ the human hearing range?
a.
b.
c.
d.
2.
The range of ultrasonic frequencies is defined as?
a.
b.
c.
d.
3.
The technician
Crystal timing mechanism
Amount of triglycerides in the area being treated
The frequency at which the current changes polarity
Local temperatures during radiofrequency can be as high as?
a.
b.
c.
d.
6.
Piezoelectricity
40,000 Hz
Inverse piezoelectricity
Micro-bubbles
The frequency at which the piezoelectric crystal expands and contracts is determined by?
a.
b.
c.
d.
5.
A constant frequency of 40 kHz
20 kHz – 70 kHz
20 kHz and above
20 kHz and below
Ultrasound is generated by a process known as?
a.
b.
c.
d.
4.
Above
Below
Within
None of the above
36.9o C
50o C
55o C
70o C
Two modalities of “Ultra-Focus” cavitation devices are?
a.
b.
c.
d.
Ultrasonic and lymphatic
Ultrasonic and radiofrequency
Ultrasonic and fractional laser
Radiofrequency and IPL
7.
A technique that helps flush clogged lymphatic vessels and glands is known as?
a.
b.
c.
d.
8.
To facilitate the treatment and to obtain the best results, the patient should:
a.
b.
c.
d.
9.
Plumbium zirconium titanate
Ruby
Alexandrite
Neodymium yttrium aluminum garnet
During ultrasonic treatment, the technician should avoid all of the following except?
a.
b.
c.
d.
13.
Liver failure
Active tuberculosis
Pacemaker
Cellulite
The crystal commonly used in an ultrasound unit is called?
a.
b.
c.
d.
12.
6 - 12
Only 1 is sufficient
20 – 30
A minimum of 70
Contraindications to receiving ultrasonic cavitation include the following, except?
a.
b.
c.
d.
11.
Consume a high calorie diet
Avoid drinking water
Drink plenty of water
Avoid exercise
How many ultrasonic cavitation treatments are recommended for optimal results?
a.
b.
c.
d.
10.
Ultrasonic cavitation
Lymphatic drainage
Body wrapping
Massage therapy
Using over the bones
Talking to the patient
Holding the sound head in one place
Applying heavy pressure to area of treatment
Triglycerides are broken down into what water-soluble product?
a.
b.
Adipose tissue
Fatty acids
c.
d.
14.
The effective frequency range for ultrasonic cavitation is?
a.
b.
c.
d.
15.
Liposuction
CO2 laser resurfacing
Erbium treatment
Fat transfer
During lymphatic technique, hand piece pressure has to be about?
a.
b.
c.
d.
19.
Velocity
Forced cavitation
Timed event
Frequency
Ultrasonic cavitation is similar to what cosmetic procedure?
a.
b.
c.
d.
18.
Medium
Transmitter
Gas
Liquid
The number of oscillations per second is known as?
a.
b.
c.
d.
17.
35-45 kHz
20 – 70 kHz
10,000oC to 70,000oC
98.6oF - 108.6oF
The matter that supports the sound is called?
a.
b.
c.
d.
16.
Glycerol
Glucose
Two times less than in cavitation movements.
Two times more than in cavitation movements.
The same as in cavitation movements.
None of the above
When performing radiofrequency, all of the below are common recommendations, except?
a.
b.
c.
d.
Do not hold the RF hand piece in one place
Do not apply heavy pressure to the area of treatment
Direction in RF must follow massage body lines
None of the above
20.
What processes are stimulated when radiofrequency heats up the deep targeted area
between 40 and 55 degrees Celsius and do not damage the surfaces of skin.
a.
b.
c.
d.
21.
During a radiofrequency skin tightening treatment, what layer of skin is being affected?
a.
b.
c.
d.
22.
Kidney failure
Pregnancy
Pacemaker
Fair skin
The name of uncharged particles that represent the radio waves?
a.
b.
c.
d.
25.
Glycol
Glucose
Glycogen
All of the above
Contraindications to receiving radiofrequency are all, except?
a.
b.
c.
d.
24.
The collagen tissue
Dermis and subdermis
Epidermis
Fat tissue
10% products of the emulsified fat are reabsorbed in the blood stream where released
triglycerides will be transformed to:
a.
b.
c.
d.
23.
Synthesize new collagen
Contraction of the collagen fibers
Tightens the skin
All of the above
Electrons
Protons
Photons
Neutrons
During cavitation and radiofrequency, direction of the movement of the hand piece must be
_________in the abdominal area.
a. Clockwise
b. Counter clockwise
c. Simple
d. Does not matter