Electroterapia en fisioterapia
Icono de contenido 24/01/2021 12:23:40

Dosage in ultrasonotherapy

Automatic translation from Spanish

Page index

Contains templates for interactive calculations

Applying ultrasonotherapy does not consist to move the head for a while on the patient's skin.

Ultrasound therapy, or US application, is the technique more complex electrotherapy, provided that it is intended to dose them correctly. It is understood that it is not the same:

Suggestions on how to apply US we find several in the literature: some recommend that it always be pulsed, others that always in continuous, others with fixed head, others always in movement, some always 5 minutes, others 10 minutes, etc, etc.

So much suggestion means that you do not know how to do it or what Interestingly, for some "convenient" reason, a certain methodology.

The best empirical and most classical suggestion from the origins of the technique is the one that proposes:

This proposal is very interesting because it includes all the parameters, but it is the account of "the grandmother" who only had the fingers. Well, the moment we modify any parameter we are already lost.

Above he asks: how do we conjugate all this? Well knowing well each parameter, what it means and what it implies in the session. Let's see:

1 Mhz penetrates more and supports more power in W/cm2 than 3 Mhz. With 3 Mhz we could reduce it by 1/3 of the power that would be applied with 1 Mhz.

The power of the continuum is named, the pulsed power is that referred to continuously reduced to the percentage or to the fraction in which we adjust the pulse, that is, the effective power.

The Potency is not the dose , Potency is the work you do the machine just in 1 s; and the session lasts more than 1 s. ¡¡ NEVER CALL THE POWER INTENSITY !!.

We can operate with the power of the entire head or with the power emitted for each cm2 head. It is better to use the latter because that is how we contemplate the real emission surface (ERA) on the head.

Power is how fast it is applies an energy. With a lot of power (the supply is very accelerated) does not give the body time to absorb it. With a little power (very slow energy supply) does not accumulate and is not produces therapeutic effect. Too much power produces a puncture in the patient during the session.

What is the proper wattage? the one that patient tolerate and just before pain. It is usually manifests as well-perceived heat. Less power is cause of low therapeutic efficacy. To find the right power you need two or three scoring sessions.

The head can be used fixed or mobile. NEVER MIX THE TWO SHAPES IN THE SAME SESSION. The treated area is defines well, delimits and distributes the head sweep in a homogeneous by the decided surface. & nbsp; In small areas little power and in large areas more power How much? To see in apuntes de electroterapia (PDF) in the section on US doses the tables of potencies according to surface and those of doses in some pathologies. View PDF of dosis en US.

The treated surfaces must not exceed the 90 or 100 cm2.

What is the dosage? is the amount of energy that is deposited on the patient at the end of the session, but distributed among the cm2 of the treated area. However, that amount that you will receive when the session ends, we have to decide before starting treatment or session.

The dose or amount of energy that "WE WANT" to apply, is the product of multiplying the power device for the duration of the session and distribute it between the surface of the treated area. That result is J/cm2. & Nbsp; How do we solve this problem? physics and mathematics provide the formula.

The problem is: If we intend to deposit 40 J/cm2; on 60 cm2; with continuous US; at 1 Mhz; set to 1.5 W/cm2; with a 5 cm2 head; How long will the session last?

Physics gives us the solution (and Let's stop "other nonsense"). We develop:

Power in W/cm2 * ERA * % * time in seconds
Dose =

Surface treated in cm2

The factor of [% or fraction] refers to the continuous or to the percentage of pulsed.

All are considered parameters, MINUS ONE, in the previous formula, we adjust them before starting the session and they are not modifiable, the The exception is time and can act as an unknown. Thus, the formula resulting will be:

Dose x surface in cm2
40 J by cm2 x 60 cm2

time =
= 320 seconds (3.3 minutes)

W/cm2 x ERA x 100% continuously
1.5 W/cm2 x 5 x 100%

Other suggestions can be considered for some pathology in concrete or profit interests, but if we intend to presume for "scientism", this is the correct formula.

Logically it implies that if we apply pulsed, efficiency is lost in the power, so in some way we must compensate it.

In the following calculation template for dose US, we can enter and modify the values in the double-traced boxes to find time values correct.

By default values are proposed to work in continuous; but if we want to do it in pulsed, in the FRACTION OF RIGHT we put the values of the fraction corresponding to the pulsed that we would use. The blue buttons select us the most common values.

Continuing with the pressed, in the FRACTION OF THE LEFT we introduce the inverse values to those of the fraction of the right or PULSE REDUCING FACTOR. This is well because & nbsp; we should raise the set power to higher values than continuous posts How much? & nbsp; to the levels indicated by the COMPENSATED POWER box, and that the equipment allows it.

Further on you will find another link to another template with another formula to use at will, if desired compensate for a certain increase in time in order to cancel possible, deficiencies in the application of the technique. SOIL INCLUDE A PERCENTAGE BETWEEN 5% AND 20%.

Formula to dose ultrasonotherapy
Ultrasound therapy dosage


Sp. in cm2


|  W/cm2
|  W/cm2



Value of power to compensate, in case of using pulsed,
to keep the same session time.

J. Totals


W effective

% / 60

Click on the sign [=] to see results

Element to present it well on computer screens over 500 pixels wide

The following template modifies the calculations so that the powers have been compensated so that the session is keep at the same time and for the patient to receive the same power that was programmed continuously.

We will see that values appear in the power already compensated that are not practical, because the equipment does not allow, but we can observe, learn and analyze the variability that is produced.

Video on handling formulas for ultrasonotherapy

Note to manufacturers

It is time for manufacturers to modernize the design of their equipment ultrasonotherapy, where they include the parameter of J / cm 2 that are intended to be applied to patients, along with the other parameters surrounding the technique and that the session time is calculate automatically.

Pantalla de US

Correct dosage screen.

Likewise, it is important to look for simple and cheap ways that we indicate the state of the heads in terms of their capacity to emission and possible power losses.

Medidor de US

Homemade US meter, simple but efficient.

Ultrasound application video

Ultrasonotherapy Dosing Video

Multiple head

This type of ultrasound application is not very suitable, and if the dosage is not precise well, they tend to generate "burns by US ". The causes of these burns are in the bad balance of any of the emitters, in adjusting a lot of power and in leaving them time excessive for that "... we no longer have to be bored shaking the head. . . . ".

Bibliographic reference: Simply the logic of physical

Rodriguez Martin, JM


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Nota sobre electroterapia

Nota al público general

Las técnicas de electroterapia no consisten en aplicarse un aparato “que alivia o elimina los dolores” y aplicárselo sin más. O usar un potenciador muscular que publicita “menganito de tal” y . . . ¡a ponerse fuertes!. Estas técnicas requieren de una base de conocimientos que el profesional conoce para ajustar los parámetros, situar los electrodos, dosificar correctamente e indicar la metodología de tratamiento.

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José Mª Rodríguez Martín

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