Ultrasound Therapy:
Definition
Ultrasound; appear waves vibrating at radio frequencies above those that the human head can hear, greater than 30, 000cycles per second (hertz, Hz).
Therapeutic ultrasound is always that which is used for therapeutic (rather than diagnostic) purposes and is particularly usually produced at just one million cycles per secondly or 1 megacycle (MHz). Generally, US frequency is definitely between 0. 7 in addition to 3. 3 MHz.
Release
Ultrasound was first researched in Europe and was shown in the United States in the early 1950s, since this time, the use of ultrasound has grown, and it remains my modality today.
Mechanism regarding action
The US is made by a high-frequency alternating current getting applied to a crystal manufactured from quartz or a synthetic (i. e. barium titanate or perhaps lead zirconate). The current will cause the crystal to curve, first in one direction and after that the other, as the current alternates. This deformation of the Ravenscroft creates what is called piezoelectric energy. The vibration vitality is transferred to a steel plate, usually nickel-plated instruments, and then to the patient’s tissues. The crystal and steel plate are housed inside the transducer or sound brain of the unit.
Physical qualities
It is not transmitted through a machine
It is transmitted poorly by means of gases
It is transmitted very best through gas-free liquids and also high-density solids
The gaming console
Similar to a radio transmitter.
Possesses an oscillator that produces electromagnetic waves at high frequencies.
Transducer head
Converts electromagnetic surf into sound waves.
A more substantial transducer surface is better (7-13cm*), but small enough to hold skin contact.
Waves usually are emitted in a cylindrical shaft perpendicular to the traducer floor. Therefore hold the transducer crown parallel to the tissue floor.
Never allow the beam to help shoot straight into the air not having gel or water that may damage the crystal clear.
To test crystal: water for the head, turn up the level the water should stream.
Coupling agents
Air does not carry out well, must use a coupling medium. Use a commercial cream, not mineral oil and many gels will contain elements that can promote healing, vit E, and aloe.
Attenuation
As the US travels by human tissue, it little by little decreases in intensity on account of attenuation. Attenuation is the reaction of absorption, reflection and refraction, with absorption accounting for around half of the attenuation.
– Amino acids are the major absorbers folks
– Increase protein written content increase absorption
– Damaged tissues with high water content minimize absorption (waves pass through)
– Homogenous tissues minimize absorption (fat)
– Heterogeneous tissues, and fascia planes enhance absorption
e. g. bone\ periosteum, fat \ muscle tissue, diff muscle groups.
– Calcaneus reflects waves, which satisfy incoming waves: resonance for that reason heat production (periosteal burning)
– Metal artefacts shows waves but absorb high temperature therefore caution
Absorption
The conversion process of the mechanical energy among us into heat is listed as an absorption coefficient which is dependent on tissue type along with frequency. This coefficient is usually expressed in decibels/cm which is highest for tissues while using the highest collagen content along with an increase in proportion to the US ALL frequency.
Absorption coefficients throughout decibels/cm at 1 along with 3 MHz
Half interesting depth
The depth of muscle at which the US intensity is actually half its initial strength is frequency and cells type dependent
Half absolute depths in mm at one and 3 MHz
Representation
Is the redirection of an event beam away from a highlighting surface at an angle equal as well as opposite to the angle associated with an incidence? US waves tend to be reflected at tissue barrière with most reflection happening where there is the greatest difference between the acoustic impedance of surrounding tissues.
There is a 100% representation of US at an air-skin user interface and only a 0. 1% reflection at a couple of medium-skin interfaces. In the body the majority of reflection approx 35% happens at the soft tissue-bone user interface.
Refraction
The redirection of the wave at an interface
Whenever refraction occurs, the US influx enters the tissue at one angle and proceeds through the tissue at various angles.
Frequency
The number of compressions-rarefactions cycles per unit of your time is expressed as (hertz). Growing the frequency decreases the actual depth of penetration.
Utilize 1 MHz for cells up to 5 cm heavy and 3 MHz with regard to tissue 1 to 2 cm heavy.
Dosage
There is no certain method of exactly calculating how much power is absorbed in any specific tissue, the decision about dose is a matter of judgement somewhat. This judgement must be in line with the known factors governing ultrasound absorption and is based on the subsequent:
Mode of delivery:
— Continuous output
Continuous shipping of US throughout the treatment time period
Used sub-acute as well as chronic stages
– Pulsed output
Sound on and off at the same time (variable ratio)
I. electronic. 20% or 1: five duty cycle is upon 20% of the time of 85% of the time: on for 2ms off for 8ms
Whenever ultrasound is delivered within pulse mode, having a 20% duty cycle or even lower the heat generated at that time is dispersed throughout the off time.
Used much more for the acute and sub-acute stages where heat is not really desirable. Also pulsed ALL OF US has been shown to increase cellular permeability more than the constant US (see below), especially at one: 5 at an intensity associated with 0. 5-0. 75 W/cm.
Power
The amount of acoustic power per unit time (Watts)
Intensity
The power per device area of the transducer head is indicated in Watts/cm and is restricted to 3W/cm
The intensity used should be altered in accordance with the size of the lesion (chronic greater than acute) tissue type (see above) and lower intensities intended for higher absorbers.
When making use of US for nonthermal consequences rule of thumb, is to use 0. your five to 1. 0 W/cm. Intended for thermal effects when using some sort of frequency of 1 MHz how to use intensity of between 1 ) 5 to 2 . zero W/cm, at a 3MHz occurrence usually an intensity involving 0. 5 W/cm is enough due to the energy being consumed in a smaller more somero volume of tissue. When planning to achieve thermal effects you anticipate the patient to feel mild temperatures rising after 2 to 3 minutes involving treatment, if this does not come about increase the intensity.
Time
How much energy is applied to the damaged tissues and hence the effects are dependent not simply on the intensity but also time applied. In general, the treatment timeframe should be increased when decreased intensities or lower radio frequencies are used.
Minimum treatment times are viewed to be 1-2 min, optimum 10-15 min. It is also recommended that chronic lesions take advantage of longer treatment times.
Effects of ALL OF US on human tissue
Energy effects
The friction brought on by the vibration of the substances within the patient’s tissues will certainly produce heat. Therefore ALL OF US can be used as a thermal real estate agent to increase the temperature associated with deep tissues on average smooth tissue temperature has been shown
to improve by 0. 02C each minute at 1 W/cm in 1MHz. The thermal results are similar to thermotherapy (see thermotherapy notes) however US may heat deeper structures and is applied more accurately than, shallow heating agents. The US can also be selective and will heat cells with a higher absorption agent (bone, tendons, ligaments, combined capsules, fascia) more than individuals with low coefficients (fat, muscle).
To increase heat being shipped the duration and/or strength can be increased. Frequency can affect penetration with 3MHz will heat tissue approximately 1 to 2 cm deep, in contrast to 1MHz will heat muscle up to 5cm
Note that using 3MHz the max temp is higher, but the interesting depth of penetration is lower.
Low Thermal effects
Cavitation
Cavitation is the formation of very small gas or vapour recorded bubbles in the tissues resulting from ultrasound. During the compression, cycle bubbles are compressed and through the rarefaction phase, they grow.
Stable cavitation occurs when the pockets oscillate in size within the ultrasound pressure waves but continue being intact and when associated with audile steaming, is considered to have beneficial value. See below
Transitory, transitive cavitation occurs when the volume of real estate changes rapidly and when compared with collapse causing high pressures along with temperature changes, resulting in yucky tissue damage and free significant release. This happens at excessive intensities
Micro-streaming
As a result of cavitation, there is a localised, unidirectional water movement around the vibrating real estate. These very small fluid activities around cells are called micro-streaming and are believed to play a large role in the therapeutic result of US by altering typically the permeability of cell écorce to increase the diffusion pace of ions across the écorce, e. g. Ca which often act as a second messenger, may well stimulate the repair course of action. Na, which alters electrical power activity in nerves, for that reason could be involved in pain relief. Likewise associated with increased mast cell phone degranulation, increase chemotactic variables, histamine release increased macrophage responsiveness and increase the pace of protein synthesis by simply fibroblasts. All of which are considered to enhance healing.
Acoustic internet streaming
This is a steady circulatory movement due to radiation torque which is thought to alter cellular tasks by transporting martial form part of the US field to a new.
Micro-massage
The waves regarding compression and rarefaction may possibly produce a form of micro-massage which may reduce oedema and pack in adhesion at high features.
Phonophoresis
Is the application of PEOPLE in connection with a topical medicine preparation as a couple of methods as US pulsation’s boost skin absorption of chemical compounds i. e.
counter problems, vitamins, salicylates etc.
