BTL-4000
Magnetotherapy
U S E R ’ S G U I D E
110DA03/03/2008EN
CONTENTS |
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1. |
M AGNETOTHER APY ...................................................................................... |
. 4 |
2. |
MAGNETOTHERAPY – PHYSICAL BACKGROUND .............................................. |
5 |
2.1 |
Magnetic Field ....................................................................................................................................... |
5 |
2.1.1 |
Stationary Magnetic Field................................................................................................................. |
6 |
2.1.2 |
Alternating Magnetic Field................................................................................................................ |
6 |
2.1.3 |
Pulse Magnetic Field........................................................................................................................ |
6 |
2.2 |
FMF Technology.................................................................................................................................... |
7 |
2.3 |
Magnetic Field Units .............................................................................................................................. |
8 |
3. |
THERAPEUTIC EFFECTS OF MAGNETOTHERAPY ............................................ |
10 |
3.1 |
Analgesic Effect................................................................................................................................... |
10 |
3.2 |
Antiphlogistic Effect ............................................................................................................................. |
10 |
3.3 |
Trophic Effect ...................................................................................................................................... |
11 |
3.4 |
Myorelaxation and Spasmolytic Effect ................................................................................................. |
11 |
3.5 |
Vasodilatation Effect ............................................................................................................................ |
11 |
3.6 |
Antiedematous Effect........................................................................................................................... |
11 |
4. |
RECOMMENDED DOSAGE OF MAGNETOTHERAPY .......................................... |
12 |
5. |
BIBLIOGRAPHY ............................................................................................ |
13 |
6. |
SETTING AND CONTROL OF MAGNETOTHERAPY – TECHNICAL PARAMETERS . 16 |
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6.1 |
Magnetic Field Intensity ....................................................................................................................... |
16 |
6.2 |
Therapy DURATION............................................................................................................................ |
16 |
6.3 |
Physiological Effects............................................................................................................................ |
16 |
6.4 |
Selection of Therapy............................................................................................................................ |
16 |
6.4.1 |
Magnetic Pulses............................................................................................................................. |
17 |
6.4.2 |
Series of Magnetic Pulses.............................................................................................................. |
17 |
6.4.3 |
Continuous Magnetic Field............................................................................................................. |
18 |
6.5 |
Pulse Shape ........................................................................................................................................ |
19 |
6.5.1 |
Rectangular Pulses ........................................................................................................................ |
19 |
6.5.2 |
Rectangular Protracted Pulses ...................................................................................................... |
20 |
6.5.3 |
Exponential Pulses......................................................................................................................... |
21 |
6.5.4 |
Sinusoidal Pulses........................................................................................................................... |
22 |
6.5.5 |
Triangular Pulses ........................................................................................................................... |
22 |
6.6 |
Modulation ........................................................................................................................................... |
23 |
6.6.1 |
Random Frequency........................................................................................................................ |
23 |
6.6.2 |
Burst............................................................................................................................................... |
23 |
6.6.3 |
Sine Surges ................................................................................................................................... |
23 |
6.6.4 |
Trapezoid Surges........................................................................................................................... |
24 |
6.6.5 |
Symmetric Surges.......................................................................................................................... |
24 |
6.7 |
Test of Connected Applicator .............................................................................................................. |
25 |
7. |
APPLICATORS ............................................................................................. |
26 |
7.1 |
“Disc" Applicator .................................................................................................................................. |
26 |
7.1.1 |
Technical Parameters .................................................................................................................... |
27 |
7.1.2 |
Shape of the Magnetic Field of the Applicator................................................................................ |
27 |
7.2 |
“Double Disc" Applicator ...................................................................................................................... |
28 |
7.2.1 |
Technical Parameters .................................................................................................................... |
28 |
7.2.2 |
Shape of the Magnetic Field of the Applicator................................................................................ |
29 |
PAGE 2 OF 35
7.3 |
“Multi Disc" Applicator.......................................................................................................................... |
30 |
7.3.1 |
Technical Parameters .................................................................................................................... |
30 |
7.3.2 |
Shape of the Magnetic Field of the Applicator................................................................................ |
31 |
7.4 |
“Solenoid 30” Applicator ...................................................................................................................... |
32 |
7.4.1 |
Technical Parameters .................................................................................................................... |
32 |
7.4.2 |
Shape of the Magnetic Field of the Applicator................................................................................ |
32 |
7.5 |
“Solenoid 60” Applicator ...................................................................................................................... |
33 |
7.5.1 |
Technical Parameters .................................................................................................................... |
33 |
7.5.2 |
Shape of the Magnetic Field of the Applicator................................................................................ |
33 |
7.6 |
“Linear" Applicator ............................................................................................................................... |
34 |
7.6.1 |
Technical Parameters .................................................................................................................... |
34 |
7.6.2 |
Shape of the Magnetic Field of the Applicator................................................................................ |
34 |
7.7 |
“Solenoid 70” Applicator ...................................................................................................................... |
35 |
7.7.1 |
Technical Parameters .................................................................................................................... |
35 |
7.7.2 |
Shape of the Magnetic Field of the Applicator................................................................................ |
35 |
PAGE 3 OF 35
1. MAGNETOTHERAPY
Magnetotherapy is one of the basic physiotherapy procedures. Its basic form - application of a static magnetic field, i.e. a permanent magnet - has been used since time immemorial as one of the natural healing sources. However, only the coming of electronics and powerful switching elements enabled the rapid development of lowfrequency pulse magnet therapy, the effects of which are several times greater than those of the static magnetic field. Recently performed studies imply that therapy performed by means of pulse electromagnetic field is up to 100 times more effective than the application of a stationary magnetic field. That is why pulse magnetotherapy is becoming one of the most widespread physiotherapy methods nowadays. In some conditions (e.g. chronic pains in degenerative articular diseases) this method has proven successful as therapy withlong-lasting therapeutic effect even when other therapy methods failed.
Pulse magnetotherapy can be very effective in case of correct indication and application. It can also be recommended for use in combination with other therapy methods, such as pharmacotherapy, the effects of which are usually supported by magnetotherapy. That is why magnetotherapy should neither be left out in case of a comprehensive approach to treatment, nor given preference as monotherapy.
The latest findings about the physiological response of the body to the electromagnetic field imply the following effects of magnetotherapy:
•analgesic effect,
•antiedematous effect,
•antiphlogistic effect,
•trophic effect (acceleration of healing and growth),
•myorelaxation and spasmolytic effect,
•vasodilatation effect.
The following chapters contain a brief explanation of the physical background of magnetotherapy and the physiological mechanisms of its effect with the emphasis on application in individual fields of medicine.
The Encyclopaedia, which is a separate attachment to this User’s Guide, contains a list of recommended parameters of magnetotherapy in selected diagnoses.
The design of this device utilizes the experience acquired during the development, manufacturing and long-standing clinical operation of the BTL-09 device and state-of-the-art devices in the BTL-4000 and BTL-5000 series. During the design of new magnetic applicators for this device, there was developed a brand new technology – so-called “FMF” (“Focused Magnetic Field”) technology. Thus we managed to increase the electromagnetic field intensity on the patient’s side and significantly reduce the electromagnetic field intensity on the applicator’s side, turned away from the patient. Colloquially put, the magnetic field was moved from the improper side to the side where it is desired.
Thanks to these construction elements and thanks to state-of-the-art sources based on the principle of electronic switching elements, we have managed to reduce the power consumption significantly while preserving the same electromagnetic field intensities.
Note
The authors of this User’s Guide are aware that such a small space is not sufficient for a detailed description of the entire magnetotherapy issue. They therefore had to make some generalizations and simplifications resulting from the limited scope of this text. More details can be found in the available literature (see the chapter
Bibliography).
MAGNETOTHERAPY | PAGE 4 OF 35
2. MAGNETOTHERAPY – PHYSICAL BACKGROUND
2.1MAGNETIC FIELD
The magnetic field is an integral part of the electromagnetic field, which consists of electrical and magnetic components. Both components of the electromagnetic field are mutually closely connected and cannot exist without each other, except in the following two special cases:
•electrostatic field, in which the magnetic component of the field is zero, and
•stationary magnetic field, in which the electrical component is zero.
Owing to the used frequencies up to 150 Hz and owing to the design of the BTL applicators, the magnetic component of the field predominates over the electrical. In short we will hereinafter call the field by the commonly used term “magnetic field”.
The presence of a magnetic field is sensed primarily through its force effects, by which it affects magnetically conductive things, moving charges and conductors with electric current flowing through them. The force effects are not very important for our theory, because biological objects are diamagnetic. However, it is necessary to take these force effects into account in case of metal implants, especially those which are fixed in soft tissues and are not made of antimagnetic materials.
Another interaction between the magnetic field and matter occurs at the moment when matter is exposed to the magnetic field. At that moment, individual free molecules are orientated in such a way as to minimize the energy inside the field. In case of biological objects, these forces act against the bonds between atoms, molecules and ions in the tissues, which consequently also influence the cellular processes.
The effects important for physiotherapy are based on electrodynamic induction, discovered by the physicist M. Faraday in the 19th century. In practice, if you move an electric conductor in a magnetic field, voltage appears on it. If you make a closed loop of the moving conductor, electric current will flow through it. As Faraday discovered, this phenomenon also works the other way around – if the magnetic field moves or changes in the course of time (instead of the conductor), a similar effect occurs. These discoveries were only a short remove from the application of alternating magnetic fields in therapy.
In case of living organisms, the moving charges (the conductor moving in the magnetic field) are represented by the circulating body fluids (blood, lymph). In case of exposure to an alternating magnetic field, it refers to its individual more electrically conductive parts - the vascular bed (including circulating fluids), peripheral nerves, CNS neural paths and, last but not least, also individual ions and charges on cellular membranes.
MAGNETOTHERAPY – PHYSICAL BACKGROUND | PAGE 5 OF 35
2.1.1STATIONARY MAGNETIC FIELD
A stationary magnetic field arises around permanent magnets but also around moving electric charges which move at a constant speed (direct current).
Electric charge may be carried e.g. by ions (electric current flowing in liquids) and electrons (electric current flowing in conductors). In the latter case, a magnetic field similar to that around a permanent magnet arises around the electric conductor with constant direct electric current flowing through it.
2.1.2ALTERNATING MAGNETIC FIELD
The time behaviour of this field is usually derived from the sinusoidal mains voltage. In common practice, devices most often generate fields of a frequency of 50 Hz and the sinusoidal waveform. The magnetic fields of these devices change their polarity in the course of time.
These fields, even though with much lower intensity, exist in the surroundings of each electrical conductor, transformer and motor supplied from the AC mains.
2.1.3PULSE MAGNETIC FIELD
This field is characterized by fast changes of field; individual pulses are close to rectangular pulses, their edges are very steep. That is why in a pulse magnetic field the electrical component is higher and is permanently present beside the magnetic component. Some studies, which deal with the comparison of individual magnetic field types, point out the very high efficiency of the pulse magnetic field in comparison with the stationary magnetic field. Therefore, the question arises whether the positive results of the pulse magnetic field are not caused by the more intensive electrical component of the field.
Of all the possible pulse types, the BTL – 4000 Topline device has been equipped with the following ones. These pulses cover the entire spectrum of required applications, from acute to chronic states.
•Device Options
The device can be set to generate the following pulse types:
• rectangular pulses,
•rectangular protracted pulses,
•exponential pulses,
•sinusoidal pulses,
•triangular pulses and
•continuous magnetic field.
All the above listed magnetic field waveforms can be further modulated and the following surges of basic pulses can be created: 
• trapezoid surges,
•sine surges,
•symmetrical surges.
It is also possible to create groups of magnetic pulses - so called bursts.
The option of random sweep of the basic selected frequency is available, too.
All these parameters can be set in the well-arranged manual mode. Preset programs and recommended diagnoses are available, too.
MAGNETOTHERAPY – PHYSICAL BACKGROUND | PAGE 6 OF 35
2.2 FMF TECHNOLOGY
FMF = Focused Magnetic Field
In dependence on their spatial distribution, magnetic fields are divided into uniform and non-uniform. The uniform field has the same intensity and the same direction in all points of space.
The applicators were designed using state-of the-art ferromagnetic and magnetic materials which enable highly effective magnetic concentration systems to be assembled. These elements focus the electromagnetic field onto the desired space towards the treated body part. Therefore, the magnetic field of the BTL applicator is intentionally non-uniform and focused.
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Standard Magnetic Applicator |
FMF Technology Applicator of DISC Type |
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The sides of the applicator are identified as the patient side, from which the magnetic field is emitted to a higher extent, and the operator side, where the field intensities are several times lower.
blue indicator light
Patient / Application |
Side turned away from the patient |
Side of the Applicator |
(operator side) |
The side is marked with a pictograph of a “patient in the magnetic field”. The intensities on this side of the applicator are much higher than those on the operator’s side. During operation of the device, the operator should not touch this side of the applicator.
The side marked with the BTL logo. It is also equipped with a blue indicator lamp which indicates operation of the applicator (continuous light, fast blinking) and its readiness for operation (slow blinking).
MAGNETOTHERAPY – PHYSICAL BACKGROUND | PAGE 7 OF 35
Example of possible use of the magnetic applicator with FMF technology:
The magnetic field of the solenoid type applicators is focused inward:
Standard applicator |
and its |
FMF technology applicator |
- magnetic field |
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- focused magnetic field |
2.3MAGNETIC FIELD UNITS
The BTL-4000, BTL-4000 Topline and BTL-5000 devices use for magnetic field induction (B) the unit according to the SI international unit system – Tesla (T) or its one thousandth - millitesla (mT).
Owing to the fact that the formerly used unit Gauss (G) has the following relation to millitesla:
1mT = 10 G, the display shows the converted value in mT/10.
Then, 1mT/10 = 1G.
Other magnetic field units:
Then the unit of magnetic field intensity is ampere per meter (A/m).
An older unit of intensity is Oersted (Oe).
The relation between these two units is: 1 Oe = 79.577 A/m.
The relation between magnetic induction and magnetic intensity is the following:
B = µr . µo . H
MAGNETOTHERAPY – PHYSICAL BACKGROUND | PAGE 8 OF 35
where: B is the magnetic induction
H is the magnetic intensity
µo is the permeability of a vacuum, which equals 1.2566 . 10-6
µr is the relative permeability of the environment, which expresses the magnetic properties of the environment
•for a vacuum it equals 1
•for magnetically conductive materials, the values are much higher than 1 (e.g. for steel, the values range from 100 to 5800)
•for air, the value is similar as for a vacuum, i.e. approximately 1 (1.00000038 to be accurate)
•biological tissues from this view can be compared to water, for which the value equals 0.999991
It can be calculated that for biological tissues a magnetic field induction of 1mT corresponds to a magnetic field intensity of 795.8 A/m.
MAGNETOTHERAPY – PHYSICAL BACKGROUND | PAGE 9 OF 35
3. THERAPEUTIC EFFECTS OF MAGNETOTHERAPY
Magnetotherapy is one of the most commonly used physiotherapy procedures. This method has proved successful in some diseases as therapy with long-lasting therapeutic effect (e.g. in chronic pains of vertebrogenous aetiology or in degenerative joint diseases) even when other therapy methods have failed. However, it is necessary to consider that, like every therapeutic procedure, magnetotherapy also has a certain failure rate.
It has been proved that for the treatment of patients in acute stages it is better to use a static magnetic field at the beginning; in chronic diseases it is better to use pulse magnetotherapy. Application of magnetotherapy must always be based on a thorough medical history and detailed examination of the patient.
It is suitable to take into account that the natural magnetic field of the Earth equals approximately 0.04 – 0.05 mT (0.4 – 0.5 Gauss). The BTL-4000, BTL-4000 Topline and BTL-5000 devices work with magnetic fields, the intensity of which may be up to 1000 times higher. Therefore, the application requires particular caution, also with respect to the fact that man has no specific receptors for a magnetic field and therefore does not perceive it directly – unlike e.g. an electric current.
The latest findings about the physiological response of the body to the electromagnetic field imply the following effects of magnetotherapy:
•analgesic effect,
•antiphlogistic effect,
•trophic effect (acceleration of healing and growth),
•myorelaxation and spasmolytic effect,
•vasodilatation effect,
•antiedematous effect.
3.1ANALGESIC EFFECT
The analgesic effect of magnetotherapy applies in most algesic states of muscular as well as articular aetiology. A detailed description of this effect is quite complicated; its physiological effects have been specified in recent years. According to these findings, the analgesic effect of magnetotherapy is accounted for by the increased secretion of endogenous opioids caused by the myorelaxation, antiphlogistic and antiedematous effect and maybe also the impact on presinaptic inhibition of nociceptive signals at the level of the medullary dorsal horns.
The treatment should be combined with aimed pharmacotherapy, manual treatment and relaxation therapy, at least in the initial stage.
3.2ANTIPHLOGISTIC EFFECT
This effect has not been convincingly explained so far, but recent studies agree on the following principle:
The antiphlogistic effect is induced by increased phagocytosis of neutrophils and the increased production of hyperoxide. This is followed by the induction of hyperoxide dismutase bound to endothelium, which all probably leads to a higher concentration of hydrogen peroxide in the exposed area. Owing to the fast that hyperoxide inhibits the activity of catalase, the hydrogen peroxide is not degraded and thus is able to destroy leucotriens, some of the strongest activators of phagocytosis.
THERAPEUTIC EFFECTS OF MAGNETOTHERAPY | PAGE 10 OF 35
This mechanism also explains the initial controversial action of the magnetic field in sterile inflammations as well as in microbially induced inflammations. This effect also accounts for temporary impairment of rheumatic conditions during the first two or three exposures, when the inflammatory symptoms are intensified by increasingly produced hyperoxide.
Simultaneous medication and physical therapy is necessary; the patient must be monitored during the therapy and in case of longer negative reaction, the therapy must be stopped.
3.3TROPHIC EFFECT
The magnetic field accelerates healing of the skeleton and soft tissues. It is caused by better blood circulation in the exposed area and by the irritation of cytoplasmatic membranes. This activates the metabolic chain, the key point of which is a change in the cAMP/cGMP ratio.
The acceleration of healing, especially of the skeleton, is described in detail in the literature (Chvojka, 1993, 2000).
3.4MYORELAXATION AND SPASMOLYTIC EFFECT
Increased blood circulation in the area improves the washing away of acidic metabolites which cause painful irritation. In the muscles exposed to the magnetic field there also proceeds increased activity of LDH (lactate dehydrogenase) and efflux of the Ca2+ ion from muscle cells.
3.5VASODILATATION EFFECT
This effect is caused by the efflux of Ca2+ ions, which causes relaxation of the tonus of the vascular musculature and precapillary sphincters. Probably the n. vagus is also directly influenced and the increased metabolic activity of cells in the exposed area results in the creation of EDRF and prostacyclins.
3.6ANTIEDEMATOUS EFFECT
This effect results from the two above-described effects - the antiphlogistic effect of the magnet and acceleration of healing and improved blood circulation.
THERAPEUTIC EFFECTS OF MAGNETOTHERAPY | PAGE 11 OF 35
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