Gima UTC2, Инструкция по эксплуатации

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MA531_EN
EN 9
This parameter has important in the pulsated erogations, that is when a perturbation of duration m is repeated after the
time s. It is defined as ratio between the duration of the impulse m and the interval of time resulting by the sum of the du-
ration of the impulse and the duration of the interval between two following impulses (m+s). It is given in percentage (%).
TRANSDUCERS
The devices that can convert a physical quantity of a certain nature in a different nature they are said transducers. In our
case the transducer is able to change electric energy in ultrasound energy.
Very often the devices (transducers) they are able to work both as ultrasound generators (US), and as receivers. Ultra-
sound receivers are used for medical diagnosis.
Generally piezoelectric transducrers are used that, excited by an alternating current, they create some vibrations trans-
mitted to the mean of contact. The frequency of vibration of the piezoelectric crystal determines the frequency of vibration
of the ultrasounds. In the therapeutic use it is necessary to keep in mind that the depth of penetration is inversely propor-
tional to the ultrasound frequency (1 MHz around 4/5 cm - 2 MHz around 2/3 cm - 3 MHz around 1/1,5 cm).
The handpiece having the transducer, to the purpose to avoid reflections of the beam, is generally put in contact with the
skin through a GEL. This GEL has to have the followings requisite:
- it doesn’t have to be easily assorbable from the skin;
- it doesn’t have to have irritating effects for the derma;
- it has to be inactive chemicallly;
- it must have exempted from gas bubbles.
INTERACTIONS BETWEEN TISSUE AND ULTRASOUNDS
The intensity of an ultrasonic wave , that travels through a tissue, decreases when the crossed distance increase. This
attenuation of the beam happens in how much energy is partly absorbed and partly lost for phenomenons of diffusion and
reflection. Reflection occurs when the wave meets a surface of separation between two means in which, because of the
different elastic characteristics, the sound is propagated with different speed. In correspondence of this separation a part
of the wave is reflected and a part is transmitted to the second mean changing however of direction (refraction). Clearly
the entity of the reflection depends on the acoustic impedances of the two means. To make an example there is a greater
reflection in the passage from a soft tissue to the bone than viceversa.
Biophysic Effects
The interaction between ultrasounds and biological tissues produces thermal effects and not thermal ones (mechanics,
chemical, cavitation).
Mechanical effect
This effect is due to the movement of the particles of the tissues crossed by an ultrasonic wave. In presence of lack of
homogeneity, some variations of pressure are obtained that determine a movement of the liquids, an increase of the
permeability of membrane and the distribution of the tissue due to separation of the collagen fibers. This movement,
disregarding the rapidity, it is more intense than a normal manual or instrumental massage, both because it possesses
concentrations of different strengths, and because of the frequency.The pressure and traction phenomenons with con-
sequent phenomenons of contractions and expansions happen in the intimate structure of the tissues and they have
separated from brief intervals, while in the ordinary massage it is the mass of the tissue that is moved.
Chemical effects
The notable strengths of acceleration of the particles of the tissue, submitted to the passage of the ultrasound wave, they
provoke the modification of the local PH and the permeability of the cellular membranes with molecular changes.