BTL-4000
v100z1TN21/06/2004EN
BTL-4000
Ultrasound
Therapy
USER'S GUIDE
ULTRASOUND THERAPY – USER'S GUIDE
page 2 of 16
CONTENTS:
1 USER'S GUIDE ...................................................................................................................................................3
1.1 Mechanism of Action...................................................................................................................................... 3
1.2 Methods of Application...................................................................................................................................4
1.2.1 According to Application Area and Movement of the Emitter Head ..........................................................4
1.2.2 According to Application Area ..................................................................................................................5
1.2.3 According to Contact Between Emitter Head and Body Surface ..............................................................5
1.3 Ultrasound Frequency.................................................................................................................................... 5
1.4 Modes of Operation........................................................................................................................................5
1.5 Emitter Head Size ..........................................................................................................................................6
1.6 Application Time.............................................................................................................................................6
1.7 Intensity..........................................................................................................................................................6
1.8 Frequency of Treatments ...............................................................................................................................6
1.9 Combined Therapy.........................................................................................................................................6
1.9.1 Ultrasound + Low-frequency Currents......................................................................................................6
1.9.1.1 Mechanism of Action ..........................................................................................................................7
1.9.1.2 Intensity ..............................................................................................................................................7
1.9.2 Ultrasound + Amplitude Modulated Mid-frequency Currents (2-pole Interference)...................................7
1.9.2.1 Mechanism of Action ..........................................................................................................................7
1.9.2.2 Intensity ..............................................................................................................................................7
1.9.3 Ultrasound + TENS (Transcutaneous Electrical Nerve Stimulation).........................................................8
1.9.3.1 Mechanism of Action ..........................................................................................................................8
1.9.3.2 Intensity ..............................................................................................................................................8
1.10 Specific Contraindications for Ultrasound Therapy ........................................................................................8
1.10.1 Absolute ...................................................................................................................................................8
1.10.2 Relative ....................................................................................................................................................9
1.11 Therapy Prescription ....................................................................................................................................10
1.12 Instructions for the Patient ...........................................................................................................................10
1.13 Treatment Procedure ...................................................................................................................................10
2 SETUP OF ULTRASOUND GENERATOR....................................................................................................... 11
2.1 Setup and Control of Ultrasound Therapy....................................................................................................11
2.1.1 Ultrasound ..............................................................................................................................................11
2.1.1.1 Carrier Frequency.............................................................................................................................11
2.1.1.2 Duty Factor .......................................................................................................................................11
2.1.1.3 Intensity ............................................................................................................................................11
2.1.1.4 Time..................................................................................................................................................11
2.1.1.5 Pulse Frequency...............................................................................................................................11
2.1.1.6 With Electro yes/no...........................................................................................................................11
2.1.1.7 Course of Signal ...............................................................................................................................12
2.1.1.8 Physiological Effects.........................................................................................................................12
2.1.2 Ultrasound Sequence .............................................................................................................................12
2.2 Specific Settings...........................................................................................................................................12
2.2.1 Ultrasound Head Calibration ..................................................................................................................12
2.2.1.1 Start of Calibration ............................................................................................................................12
2.2.1.2 Finishing of Calibration .....................................................................................................................13
2.2.1.3 Saving of Calibration Values.............................................................................................................13
3 TECHNICAL PARAMETERS............................................................................................................................14
3.1 Parameters of Ultrasound Generator ........................................................................................................... 14
3.2 Step of Setting of the Adjustable Values ......................................................................................................14
3.3 Parameters of Ultrasound Heads.................................................................................................................15
4 ACCESSORIES.................................................................................................................................................16
ULTRASOUND THERAPY – USER'S GUIDE
page 3 of 16
1 USER'S GUIDE
Continuing education is a very important aspect of healthcare delivery. Many excellent resources are today available
to expand a user's knowledge about many aspects of ultrasound therapy. BTL recommends a thorough review of this
guide prior to operating the equipment and a search of educational reading material on the internet.
1.1 MECHANISM OF ACTION
Mechanical waves of a frequency higher than 20 000 Hz are called ultrasound. Application of ultrasound does not
generate any electric current in tissues, and thus it is classified as mechanotherapy. The frequency usually used in
physiotherapy is 0.8 – 3 MHz.
When the air gap between the emitter head and the body surface is eliminated, the emitter head vibrations are
transmitted into the tissue and propagate to the depth in the form of longitudinal waves. All cells in the path of
ultrasonic beam begin to oscillate. This causes micro-massage followed by transformation of gel into sol (jelly
structures become liquid), transformation of mechanic energy into thermal, and deep warming of tissues.
The amount of generated heat depends on the amount of absorbed energy. Other effects of ultrasound (degassing of
solutions, formation of cavities in liquids, and local alkalization) are negligible with ultrasound doses and intensities
used in physical therapy.
In order to avoid side effects, it is important to realize that molecular oscillation occurs not only in the path of ultrasonic
beam, but also in places that are distant from the area of application as a result of transmission by body fluids. This
may lead to restoration of former epistaxis or acceleration of menstruation.
The features of ultrasound beam and its distance from the emitter head determine the ultrasound field as being either
close or distant.
Close ultrasound field is characterized by low beam divergence and big intensity variations due to interferential
effects. The length of close field is directly proportional to effective radiation area (ERA – see below) of the emitter
head and inversely proportional to frequency. For example, the length of close field with 4 cm
2
ERA emitter head and
1 MHz frequency is approximately 10 cm, and for the emitter head with 1 cm
2
ERA and 1 MHz frequency it is
approximately 2 cm.
Distant ultrasonic field is characterized by increasing beam divergence, gradual decrease of intensity, and almost
no interferential effects.
Therapeutic effects take place mainly in the close field. The ultrasonic beam in the close field has significant
interferential effects (interference of applied and reflected waves) - both constructive and destructive. It results in non-
homogenous ultrasonic beam where peak levels of intensity (local increase of intensity caused by constructive
interference) may be many times higher than the pre-set value.
Beam Non-uniformity Ratio (BNR) states how many times the peaks of intensity exceed the pre-set values. This
value characterizes an ultrasound head with a given frequency. The BNR value of a good quality ultrasound head is
lower than 5. It means that if the pre-set intensity of the unit is 1 W/cm
2
, the intensity in any part of the ultrasonic beam
is not higher than 5 W/cm
2
.
The BNR of older ultrasound heads and some newer ones (some manufacturers do not mention the BNR
value) is often 20 or even more!
The Effective Radiating Area (ERA) is always smaller than the actual surface area of the emitter head (the ERA is
determined by the size of the piezoelectric crystal or ceramic table that generates ultrasound by oscillating). The
ultrasound dose (power emitted to a surface area) is, therefore, related to the ERA and not to the actual surface area
of the emitter head.
The phenomena of ultrasound refraction and reflection are caused by ultrasound wave transmission from one
tissue into another and by different transmission speed in these tissues. When applying ultrasound, it is necessary to
eliminate the air gap between the emitter head and the skin. Therefore, modern ultrasound heads have built-in optic
and/or acoustic check of insufficient contact, possibly with automatic termination of application time countdown.
ULTRASOUND THERAPY – USER'S GUIDE
page 4 of 16
Due to interference in the close ultrasound field (it reaches the highest level in the place of soft tissue/bone boundary -
up to 35%), ultrasonic beam power increases (constructive interference) or decreases (destructive interference).
In order to avoid tissue lesions at peak levels of intensity, it is necessary to move the emitter head continuously.
As a result of reflection and constructive interference, local increase in intensity and temperature may occur,
particularly in the place of periosteum/bone boundary. This increase can lead to periosteum pain during ultrasound
application. If this occurs, the intensity must be immediately lowered.
Ultrasound is primarily absorbed in deeper tissues. Since these tissues usually do not include thermoreceptors, it is
impossible to perceive local rise in temperature. The patient feels pain only if the local temperature exceeds 45
o
C and
nociceptive receptors are irritated. Most authors agree that a short-term rise in local temperature to 45
o
C is not
dangerous.
In the area of classic inflammation (edema, erythema, local rise in temperature, pain or dysfunction) additional heat
production is contraindicated, and thus only pulsed ultrasound (athermic) can be applied if necessary.
During peracute phase of post-traumatic conditions (up to 24-36 hours) the pulsed ultrasound application is
contraindicated (vibrations hinder capillary proliferation and may cause delayed bleeding).
Local rise in temperature and micro-massage have several physiological effects:
• Improvement of local circulation and thus also metabolism. Rise in temperature enhances vasodilatation
(more evident in continuous ultrasound).
• Increase in capillary permeability and increased resorption of extravasation fluid.
• Improvement of local circulation and decrease in orthosympathetic activity resulting in significant muscle
relaxation.
• Decrease in local ischaemia pain.
• Transformation of gel into sol (due to transformation of fibrinogen into fibrin, haematomas and edemas change
into gel; ultrasound dissolves this gel and speeds up resorption). As the transformation of fibrinogen into fibrin is a
basis of healing process (scar formation), it is not advisable to apply ultrasound for peracute post-traumatic
conditions.
• Improvement of tissue regeneration capabilities as a result of the above-mentioned effects.
Ultrasound has also several non-therapeutic effects that can have negative impact, such as:
• Tissue lesion - Mechanic and/or thermic tissue lesion can occur when the intensity is too high. Especially
sensitive is the nervous system (peripheral nerve) situated right on the bone (interference!) below the
surface (close field!). Impulse transmission speed in the corresponding nerve decelerates, then occurs
total (reversible) impulse transmission blockage and finally irreversible disintegration of the neuron
(myelin coats are preserved). Therefore be extremely cautious when applying ultrasound e.g. on
paravertebral muscles after laminectomy when nerve structures lose their natural bone protection.
Similarly, bone projections located just under the skin (ankles, epicondyles, spondyle spines, etc.) are
also sensitive.
• Leukocyte mobility impairment – this can be minimized by sufficient movement of the emitter head.
• Other effects (mainly caused by overdosage) are: decrease in glycaemia, increased fatigue, nervousness,
changes in appetite, constipation, increased tendency to catch colds.
1.2 METHODS OF APPLICATION
1.2.1 According to Application Area and Movement of the
Emitter Head
Static application - The head is fixed to the treated area by a special holder and it is not moved. Due to the
above-mentioned adverse effects it is the least suitable form of application.
Semistatic application - is used when the application area corresponds to the ERA of the emitter head. The
therapist continuously moves the emitter head, in spiral along the perimeter of an imaginary circle.
Dynamic application - the application area is bigger than the ERA of the emitter head. The therapist moves
the emitter head in spirals in the treatment area. The application time is prolonged proportionally according to
how many times is the application area bigger than the ERA of the head.
ULTRASOUND THERAPY – USER'S GUIDE
page 5 of 16
1.2.2 According to Application Area
Local application - Ultrasound is applied to the affected area. It is the most common way of application,
particularly suitable for local muscle spasms, chronic post-traumatic edemas, etc.
Segmental application - Ultrasound is applied to the outflows of nerve radices of the affected area (e.g.
Sudeck syndrome, Morbus Reynauld, etc. The application is paravertebral and homolateral; in the area of C
5
- Th
1
for pathologies of upper limbs and in the L
3
- S
1
area for lower limbs.
Neural application - is based on the effect of decrease in impulse transmission speed in the peripheral
nerve where ultrasound is applied. As the dividing line between the lowering of conductivity and irreversible
nerve damage (asymptomatic) is very small, this method of application is considered dangerous, and it is
used only exceptionally (e.g., phantom pain).
Radicular application - Ultrasound is applied subsequently to the corresponding spinal root and manifested
Head zone. For application above the spinal root, the same risks and limitations apply as for neural
application.
1.2.3 According to Contact Between Emitter Head and Body
Surface
Direct contact - is provided by a contact medium (ultrasound gel). This is a common way of ultrasound
application, and it is not necessary to mention it in ultrasound therapy prescription. For combined therapy
(ultrasound + electrotherapy) it is recommended to write "conductive gel" in the prescription because some
gels do not conduct electricity. The BTL ultrasound gel is conductive; if this gel is not available you can use
ECG gel or another water-based gel instead. However, never use paraffin oil, because it is non-conductive
and could damage the head.
Subaqual application. This method has a range of advantages: It uses mainly the distant ultrasound field
where interference does not occur. Furthermore, there is no need to press the emitter head against the skin
in order to maintain sufficient contact (this pressure is unpleasant or even painful for post-traumatic
conditions). In addition, this application is not limited by uneven surfaces, and ultrasound can be easily
applied to these surfaces, such as to interphalangeal joints.
Disadvantages of subaqual application include difficult handling of a special porcelain bath, limitation of
ultrasound application to acral body parts, and the risk of the therapist's hand lesions if the hand is put in
water. (It is strictly prohibited due to reflection and interference of ultrasonic waves against walls of the
porcelain bath!) Some emitter heads (even newer) are claimed to be water resistant, but if they do not have a
holder, they do not provide safe subaqual ultrasound application.
Ultrasound can be also applied via a thin-walled rubber bag (surgical gloves, condom) filled with boiled water.
However, when using this method, it is necessary to eliminate the air gap between the bag and skin (use gel)
and between the emitter head and the bag. This method is often perceived as very time-consuming.
1.3 ULTRASOUND FREQUENCY
Older ultrasound units employ a fixed frequency, usually 0.8 – 1 MHz. Newer ones are multifrequency units, the
selected frequency is determined by the target tissue; 1 MHz frequency is used for deep tissues and 3 MHz frequency
for superficial tissues.
1.4 MODES OF OPERATION
a) continuous - It is characterized by heat generated deeply in tissues. It is contraindicated in inflamed areas
and everywhere else where local warming is undesirable.
b) pulsed - together with shortening of pulse length there occurs decrease in so called Duty factor. As a result,
thermic effect is suppressed and when Duty factor is below 12.5% (1:8), athermic effect can be expected.
Duty factor (DF) can be set in pulsed mode of operation. Its value states for how many percent of the period duration
the ultrasound signal is being generated. When setting therapy parameters of BTL units, the ratio of ultrasound signal
duration to the period length is stated in brackets. This ratio is used in parameters of recommended ultrasound
therapies of BTL units. In case of continuous setting of the parameter, only the percentage expression is used.
Example:
Duty factor 25% (1:4) means that 25% (1/4) of the period is ultrasound and the rest of the period is pause.
Loading...