MODERN RADIATION SOURCES AND APPARATUS FOR
The firm "Technica", Moscow, Russia
From time immemorial, the Sun has been perceived as a source of light, warmth
and life. The use of natural light in therapeutical purposes is, probably, as
old as mankind itself. The sun light and water have always been maximum close
and available medical means. The first known mentioning of the practical use of
sun rays in prevention and therapeutical purposes dates back to the time of
Pharaoh Amenhotep's reign in Egypt (presumably from 1375 to 1358 B.C.). Medical
characteristics of the Sun are described in the works of Herodotus, Hippocrates,
A.C.Celsius, C.Galen, Abu Ali ibn Cena and others. One can say, that the Sun is
the first radiation source in phototherapy, which has a wide spectrum range,
unstable power density and unstable polarisation degree.
At the end of the last century, artificial light sources appeared, which had
a narrower spectrum range and stable radiation power, thus giving rise to an
intense development of light therapy at this period, as they showed a
considerably more prominent and lasting medical effect, than sun therapy.
Moreover, with the appearance of better controllable means of an action, it
became possible to carry out investigations of photobioactivation phenomena.
First of all, the success of light therapy is connected with the name of the
Danish physiotherapist Nilse Ruberg Finsen (1860-1904), who offered to
concentrate sun rays, simultaneously excluding visible and infra-red parts of
the spectrum, for the treatment of tuberculosis cutis (lupus), and he also
offered to treat skin pox by red light. In 1903 he was awarded the Nobel prize
in medicine for the elaboration of a new method of treatment [ 10].
The second part of the XX century was marked by the appearance of lasers -
light sources with new characteristics, such as: monochromatism, coherence,
polarisation, directivity. This fact didn't go unnoticed, and in the middle of
the 60-s the study of photobioeffects, caused by low-level intensity radiation
began. One of the first questions was the question of comparability of the
monochrome radiation of He-Ne laser and red-lamp light. V.M.Inyushin [6, 7] and
other scientists convincingly proved the laser radiation advantages, which
greatly influenced further development of low-level laser therapy.
Below is shown the classification of lasers, according to different
parameters [4,8, 12, 13, 15, 16].
1. Physical (aggregation) state of the laser working substance
- gas (helium-neon, helium-cadmium, carbon-dioxide and others);
- excimer lasers (argon-fluorine, krypton-fluorine and others);
- solid state (ruby, alumo-yttrium garnet and others, alloyed by various
- liquid (organic dyes);
- diode (arsenide-gallium, arsenide-phosphide-gallium, selenide-lead and
2. The method of working substance pumping
- electronic excitation
- injection of charge carriers
- chemical reaction
3. The wavelength of laser radiation
If the radiation spectrum is concentrated in a very narrow interval of
wavelength (less 3 nm), the radiation is considered to be monochromatic, and its
technical description includes the concrete wavelength, corresponding to the
maximum of the spectral line. The wavelength is determined by the working
substance material, but may vary slightly, depending, for example, on the
temperature. Equal wavelength can be generated by
lasers of different types, for example, the following lasers work with about
λ=633 nm: He-Ne, dye, gold vapour, diode (AIGalnP) lasers.
4. According to the character of the emitting energy, continuous and pulse
lasers are differentiated. One shouldn't mix the notions "pulse laser" and
"modulating continuous radiation" lasers, as in the second case we deal,
practically, with pulse radiation of various frequency and form, but with the
maximum power not exceeding (or exceeding insignificantly) its value in the
continuous mode. Pulse lasers have high power in the impulse, which reaches
107 W and more for some types, but the pulse duration is extremely
small, so the period average power is not high.
5. The characteristic of laser average power is very important.
- more than 103 W-high power laser
- less than 10-1 W-low power lasers.
Intermediate values aren't interesting from the point of view of this topic.
Lasers for medicine should be viewed from the position of their influence on a
biological object. In some cases "low power" - 100 W, may turn out to be quite
high. The works on laser therapy  offer to divide low-level laser radiation
into the conventional groups: "soft" -up to 4 mW/cm2; middle - from 4
to 30 mW/cm2 and "hard" - more than 30 mW/cm2. In the
therapeutical process soft radiation is used for reflexotherapy on the points of
classical acupuncture, middle-for the action on superficial pathological foci or
on projection mnes of certain organs. Hard low-level radiation, of a helium-neon
laser in particular, is recommended for the use in stomatologу, in the treatment of some dental and mouth
cavity diseases [II].
Yet, still open is the question, concerning the energy classification of
therapeutical pulse lasers, which should be viewed in complex, with regard to
the biological effect of laser radiation, taking into account not only average
outlet power, but the level of impulse power, impulse duration and laser
radiation action duration.
6. According to the degree of danger of the generated radiation for the
service staff, lasers are divided into 4 classes:
- Class 1. Laser devices are safe in the supposed conditions of
- Class 2. Laser devices, generating visual radiation in the wavelength range
from 400 to 700 nm. The eye protection is achieved by natural reactions,
including wink reflex.
-Class ЗА. Laser devices, safe for the
observation with unprotected eyes. For laser devices, generating radiation in
the wavelength range from 400 to 700 nm, the protection is achieved by natural
reactions, including wink reflex. For other wavelengths the danger for an
unprotected eye is no more, than for class 1.
The direct observation of the beam, issued by laser devices of class ЗА with the help of optic tools (binocular,
telescope, microscope, for example) may be dangerous.
- Class 3В. The direct observation of
such laser devices is always dangerous. Visible radiation scattering is usually
Note - The conditions of safe observation of the diffuse reflection for laser
devices of class 3В in the visible area:
minimal distance between an eye and a screen - 13 cm, maximum observation time -
- Class 4. Laser devices, producing dangerous scattered radiation. They may
cause skin injury, and also fire danger. One should be highly careful in using
This gradation is defined by AUSS R 50723-94 Laser Safety. General safety
requirement for the elaboration and maintenance of laser devices .
7. For the therapeutical process such laser characteristic as beam angular
divergence is very important. It is measured in degrees, minutes of arc (1/60 of
a degree), seconds of arc (1/60 of a minute) or radian (1° = π/180 ≈ 0.0175 rad.) Gas lasers have the least
divergence-about 30 seconds (≈ 0.15 mrad.) The beam divergence of solid-state
- about 30 minutes of arc (≈10 mrad.). Diode lasers have: in the plane
parallel to p-n junction - from 10 to 20 degrees (depending on the laser type);
in the plane perpendicular to p-n junction - about 40 degrees.
8. Laser efficiency.
Theoretically there is possible (quantum output) and real (full) efficiency.
The last is determined by the relation of laser radiation power to the power of
a dye source. Gas lasers have full efficiency 1-20% (helium-neon- up to 1%,
- 10-20%), solid-state - 1-6%, diode - 10-50%, in some constructions up to
95%). So it becomes clear, why only diode lasers can be used in autonomous and
portable medical equipment.
Gas lasers vary much according to the substance type: He-Ne, CO,
C02, N, Ar and others. It determines a very wide wavelength range, on
which generation is obtained. Dyeing is realised through producing a subnormal
discharge in the pipe, which is possible only with high power supply. From all
laser types, they have the minimal width of the spectral line - up to
Excimer lasers are modifications of gas lasers, they work on the
compounds, which can exist only in the excited state - halogens and inert gases.
Emit in ultra-violet part of the spectrum.
Solid-state lasers - are, mostly, alumo-yttrium garnet (YAG), alloyed by
the ions of rare-earth metals (Nd, Er, Go and others). These ions themselves
present the radiation source, while the garmet is only a matrix for their
correct position in the space. Solid-state lasers may be both - pulse and
continuous, and work on an average power level.
Dye lasers (using a liquid solution of special dyes as their working
substance) are characterised by the ability to tune to the wavelength in a wide
Diode lasers (DL) occupy a special place due to their constructive
peculiarities and physical working principles. Small sizes of the lasers are
determined by high efficiency and the necessity to provide a high density
current pumping to achieve the inverse population. The diode lasers pumping is
realised by a weak current (tens of mA) with the power about 2-3 V, whereas
other laser types require thousands of Volt. It should be noted, that we mean
exceptionally injection diode lasers, pumped by the direct current, going
through the diode structure. The drawback of DL is their high radiation
divergence, which limits its application in other, than laser therapy, spheres.
DLs work in the wavelength range from 0.63 to 15
μm. The most widespread lasers are lasers in the nearest IR area (λ=0.78-0.93 μm), based on the
crystal Ga1-x AIxAs. Diode
lasers, based on AIGalnP (λ=0.633-0.64 μm) are becoming more popular,
replacing traditional He-Ne lasers. Lasers with the wavelength 0.67 μm and average power up to 10W are used for photodynamic therapy (PDT) with the same success. There
is information about the beginning production of green (λ=0.53 μm) and blue (λ=0.42 μm) diodes Zn1-x
Cdx Se, with the power of several milliwatts and work failure time up
to 1000 hours . The table shows general types of diodes, applied in LLLT,
and their characteristics.
Mode of work
0,633 - 0,64
SDL (USA), Sanyo (Japan)|
0,633 - 0,64
SDL (USA), Sanyo (Japan)|
0,633 - 0,64
SEMCO LASER TECHNOLOGY (USA)|
0,67 - 0,69
НПО "ПОЛЮС" (Russia)|
0,67 - 0,69
0,78 - 0,8
НПО "ПОЛЮС" (Russia)|
0,815 - 0,84
НПО "ПОЛЮС" (Russia)|
0,83 - 0,87
НПО "ПОЛЮС" (Russia)|
0,88 - 0,91
НПО "ПОЛЮС", АО "ВОСХОД", (Russia)|
0,88 - 0,91
НПО "ПОЛЮС", АО "ВОСХОД", (Russia)|
0,96 - 0,99
НПО "ПОЛЮС", АО "ВОСХОД", (Russia)|
17.7 - 1 33
НПО "ПОЛЮС." АО"ВОСХОД"
The equipment, used in medicine, besides lasers themselves, also includes: a
device for radiation power modulation for continuous lasers, or master
oscillator for pulse lasers; a timer, setting the time of work; radiation power
indicator or meter (photometer); a device for bringing radiation to the object
(light guides), etc.
The most perspective in LLLT are diode lasers. Small overall dimensions, low
power supply, a wide range of radiation wavelength and power, possibilities of
direct radiation modulation, comparatively low price - all this allows to say,
that diode lasers are above competition in this branch of medicine.
Nowadays, a lot of laser therapy devices (LTD) are produced: stationary and
portable, multidiscipline and specialised; using different laser types and their
combinations, and so on. During the years of laser therapy development the
requirements to laser devices (in the general form comparatively recently) have
been formulated [14, 19]. With the increase of laser medicine level the
requirements to the modern LTD have grown as well, the next stage of laser
therapeutical equipment, as a branch of medical engineering, has come, which aim
is to formulate a unified purposeful policy in the elaboration and production,
based on the maximum close collaboration of scientists of different
specialities, general practitioners and producers.
Universality is one of the basic principles of the doctor's or
researcher's modern "instrument". The main aim of universality is to fulfil,
with minimal expenditures, numerous, contradictory sometimes, doctors'
requirements to the equipment. The block principle of an equipment construct ion
[14,19] allows to combine incompatible. The equipment, worked out on this
principle, is divided into 3 parts: a base block, radiation heads and
extensions. The principle of universality is realised in full measure in the LTD
The base block, the basis of each set, is, in fact, a supply and control
block. Its main functions -to set a mode of radiation: frequency, time, power.
Most models allow to control several parameters of radiation, the basic being
the power (average and impulse). Base blocks differ in their functional
abilities and they may be divided into two conventional types: with the fixed
set of parameters and arbitrarily prescribed. When working in certain conditions
(a medical nurse, providing the procedure, and a large number of patients), the
LTD with the "fixed frequencies" principle is more preferable. On the front
panel of a such base block there is a row of buttons with frequency indications
on each, the frequency will be automatically set after a button is pressed. The
necessary attribute in this case will be a light indication of the switch, which
confirms the correctness of the set mode. In the same way the work time is set
(timer). Such principles are realised in the LTD models "Mustang "-016,017,
A small number of fixed parameters, set by these devices, cause the limited
possibilities, which, to some extent, are eliminated with the help of the base
blocks, allowing a doctor to set necessary parameters himself (LDT "Mustang"
-models 024, and 026). The visual representation of the chosen parameters is
provided by digital indicators of different types. The devices of all types must
have radiation power indicators or meters (photometers).
One, two or even more emitting heads may bejoined up, two-channel devices
being more popular. As a rule, a modern doctor's arsenal includes several head
types, which provides a full realisation of laser therapy possibilities.
In this case, the use of different types of commutators, distributors,
splitters, etc. is very convenient, as there is no need to change a head with
each procedure, and there is a possibility to control their power independently.
One can quickly connect any of the heads, two and more heads may be used
simultaneously and in any combination, for example, red and infra-red lasers.
The interchangeability of the emitting heads and extensions allows each doctor,
according to a concrete task, to set up his own, optimal complex of equipment,
or organize multifunctional, efficient medical rooms.
The control simplicity is necessary in any equipment, including medical.
The criterion for the control simplicity estimation is time for thinking over
actions, concerning the tuning of parameters, and a number of mistakes made. The
simplicity of LTD control is closely connected with its ergonomics. The work of
a medical staff should be organised in such a way, that all their attention be
concentrated on a patient, on achieving the main task - a qualitative treatment,
and not on the equipment maintenance.
The parameter control of laser radiation is extremely important for the
validity of the applied methods of treatment and right dosage, which provides
the most qualitative and effective treatment, and also for the safety of both -
a doctor and a patient. Proceeding from these tasks, it seems necessary to
control the following parameters:
1) The radiation wavelength.
This parameter is determined by the laser type and is stated in the
documentation by a plant-producer. No additional indication is necessary.
2) The frequency of impulse radiation or of modulation.
It is set by a switch of any of the stated above types on the panel of the
base block (control block). The information about the frequency exact value is
presented either by a digital indicator in concrete figures, or by fixing of a
discrete switch in the necessary position. One should note, that in the second
case each discrete mark must provide information about a concrete parameter
value and dimension, for example, 80, 150, 300, ...Hz. It is forbidden to use
abstract figures type of: 1,2,3... with the recommendation of the producer to
look for real parameter values in the passport or maintenance manual. It is
inconvenient and, what is more important, the possibility of a mistake in
parameter setting still grows.
3) The work time (timer).
In addition to the requirements to the frequency indication, a sound
indication of the beginning and ending of the work should be provided.
4) Radiation power.
Due to the fact, that LTD action has a dose-dependable character, and the
radiation power can change through various reasons - the temperature of the
environment, energy supply and others - the compulsory control of the radiation
power is necessary for the precise action dose. If one can notice the power
decrease in lasers of the visual range, the problem of infra-red lasers power
control and safety is still acute.
The wide power range, recommended for various diseases and methods,
determines the presence of a power level regulator, and in this case the control
of these changes is quite necessary.
Emitting heads are joined up to the base block directly or through a
splitter. They consist of one or several diode lasers (more rarely of light
guides) and an electronic control circuit, which sets laser pumping current and
provides the head adaptation to the unified block supply. Sometimes, the
electronic circuit provides the realisation of other functions as well. One
should note, that it was a diode laser, which allowed to create a system of
removable emitting heads and to realise in full measure the principle of block
construction of modern equipment for low-level laser therapy.
Matrix radiators present a peculiar class of heads and autonomous
devices. Only special magnetic extensions (MM-2, MM-3) are used here. The matrix
radiator heads and autonomous devices, containing 10 pulse infra-red lasers, are
most often used in medical practice [2, 17].
Weight-dimension characteristics of the devices are not always important.
The prior characteristics remain to be those, which help to obtain the best
therapeutical effect: universality, the possibility to change and control the
radiation parameter maintenance simplicity and others. The problem of the device
dimension and weight is acute only in cases, when it is systematically moved.
Such situations most often occur in the following cases:
1) The working conditions of a doctor: on board a ship, plane, in mobile
clinics, in isolated associations (duty points, search departments,
expeditions), in camping-field conditions, etc. Country-side and private doctors
have this problem too.
2) When, with a periodical doctor control, patients perform the procedure
themselves. It is especially urgent in the treatment of heavy chronic patients,
whose movement is hampered, and also patients, who locate far from medical
institutions which allows not to break the treatment during week-ends and
In these situations, portable devices have all the advantage, as they have
minimal weight and dimensions, and can work from both - mains (through an
adapter) and a battery. In the first case, the compensation for minimal
dimensions and weight is the loss of universality and, as a result, limited
possibilities of laser therapy; in the second case, the simplicity of such
devices is even more expedient, as it allows not to worry about their wrong
application by a patient. At the same time, the abilities of portable devices
can be enough even for a general practitioner.
Autonomous portable devices of laser therapy use both - matrix radiators (LTD
"Muravei") and single, which have the advantage of being able to work with
different extensions (magnetic and optic) . They are indispensable in the
work wilt intracavitary instruments (otolaryngologic, stomatologic, etc.), but
especially well they showed themselves in reflexotherapy. For example, special
LTD "Motyilek-reflex" (with a special extension A3) was elaborated for laser acupuncture. The specialised direction of their
application determines the use of lasers with most effective for acupuncture
radiation wavelength - 0.63 and 1.3 μm.
Optic extensions for intracavitory laser therapy. Historically,
helium-neon lasers (λ=0.63 μm) were the first in
LLLT. The radiation with this wavelength penetrates into not deep tissues, so to
act on inner organs was possible only with the help of a corresponding light
guide instrument. Nowadays, with the appearance of pulse infra-red diode
lasers, and especially matrix radiators on their basis, the extensions are
refused in favour of non-invasive radiation on the projection of a sore
Significant increase of the frequency range, without upsetting the harmony of
inner rhythms, can be achieved by temporary synchronisation of the influence on
a biosystem. Basically, to achieve the synchronised LLLT action on all levels is
possible through the co-ordination of the time characteristic of the radiation
and the periods of all endogenic biorhythms, but, due to principle difficulties,
the realisation of such mode is limited by the apriori calculation of no less
than 3 inner rhythm frequencies for each patient, as it is realised in the
"Mustang-BIO" (Russia). The use of diode lasers provides small dimensions and
user's convenience .
The specialisation of some devices requires, first of all, other, than
universality, which is not always absolutely necessary, principles. To some
extent, it was already shown on the example of autonomous devices. In 1982-1989
it was informed about the effectiveness of intravenous blood irradiation (IVBI)
for the treatment of patients with stenocardia and acute myocardial infarction.
The method was also applied in other medicine branches. It required a special
equipment. For a long time, the device
АЛОК had been used, with He-Ne laser with
λ=0.63 μm and the power 2.5 mW. Now it is being replaces by devices, which use
DL with the similar wavelength. The LTD "Mulat", which has been elaborated by
the firm "Technica" and underwent technical and clinic tests, is
designated, mostly, for IVBI (maximum radiation power 4.5 mW).
The analysis of literature data allows to make the following conclusions
about the perspective development of LLLT technology:
1. The production of universal devices, built according to the block
principle (base block - emitting head - extension), and allowing to rediscipline
them for the treatment of various diseases with minimal waste.
2. The production of specialised complexes, combining, as a rule, several
methods of influence on a human organism. Such complexes, supplied with detailed
methodological equipment, allow to realise the possibilities of physical
medicine i” the treatment of 1-2 diseases with maximum effectiveness. The
devices for intravenous blood radiation, specialised according to the method of
action, can serve as an example of this direction of instrument engineering.
3. The production of small-sized, autonomous, exceptionally simple in
maintenance and maximally safe devices, meant for independent use by patients,
prescribed and controlled by doctors. Such LTD can sometimes be useful for
doctors as well.
4. The elaboration and general introduction of LLLT methods, based on the
influence of several wavelengths of the monochromic radiation (blue, green, red,
infra-red). Diode lasers with corresponding radiation wavelengths make it
realisable in a compact and universal device. There appears a possibility to
influence by all wavelengths simultaneously, or in any other combination, by
5. The replacement of continuous lasers by those, generating nanosecond
impulses with the peak power 1-10 W and having an average power 2-3 times less,
than continuous lasers, used today. Again, the only possible sources of
radiation in this case can be diode injection pulse lasers with different
6. The realisation of the multifrequent modulation mode of laser radiation by
all the hierarchy of endogenic rhythms of a concrete patient (or its maximally
possible set), ranging from ontogenesis (10-10 Hz) to the frequencies
of the optic range of electro-magnetic waves (1014 Hz), which realise
the influence. In other words, in order to get a maximum effect, one should take
into account the age of a patient and vary the radiation wavelengths. Between
these extreme points of the frequency hierarchy of life organisation, there is a
number of peculiar ranges, which are being studied today, and which should be
considered in the multifrequent mode of LLLT influence.
- Байбеков И.М., Касымов А.Х., Козлов В.И. и др. Морфологические основы
низкоинтенсивной лазеротерапии. - Ташкент:
Изд-во им. Ибн Сины, 1991. - 223с.
- Буйлин В.А. Низкоинтенсивная лазерная терапия с применением матричных
импульсных лазеров. - М., ТОО "Фирма "Техника", 1996. -
- ГОСТ Р 50723-94 Лазерная безопасность.
Общие требования безопасности при разработке и эксплуатации лазерных изделий. -
М.: Издательство стандартов, 1995. - 34с.
- Грибковский В.П. Полупроводниковые лазеры: - Мн.: Университетское, 1988.- 304с.
- Гримблатов В.М. Современная аппаратура и проблемы низкоинтенсивной
лазерной терапии // Применение лазеров в биологии и медицине (Сборник).
- Киев, 1996,
- Инюшин В.М. Лазерный свет и живой организм. - Алма-Ата, 1970. -
- Инюшин В.М., Чекуров П.Р, Биостимуляция лучом лазера и биоплазма.
- Алма-Ата, "Казахстан", 1975. - 120с.
- Кейси X., Паниш М. Лазеры на
гетероструктурах. - М., т.2., 1981.
- Москвин С.В., Радаев А.А., Ручкин М.М. и др. Новые возможности портативных
лазерных терапевтических аппаратов
"Мотылёк" // VII Межд. науч.-практ. конф.
"Применение лазеров в медицине и биологии". - Ялта, Украина, 1996.-C.I 11-113.
- Москвин С.В. Лазерная терапия, как современный этап развития гелиотерапии
(исторический аспект) // Лазерная медицина. - 1997. T.I. вып. 1. - С.45-49.
- Прохончуков А.А., Жижина Н.А. Лазеры в стоматологии / Лазеры в клинической медицине. Руководство для врачей // Под
ред. С.Д.Плетнёва. - М.: Медицина,
1996. - С.283-303.
- Справочник по лазерам / Под ред.
А.М.Прохорова, пер. с англ. - т.
1-2, М., 1978.
- Справочник по лазерной технике: Пер. с нем. - М.: Энергоатомиздат, 1991. - 544с.
- Титов М.Н., Москвин С.В. Фирма "Техника"- разработчик лазерной медицинской
аппаратуры // Лазер-маркет, (3-4)
- Электроника: Энциклопедический словарь. - М.: Сов. энциклопедия, 1991. - 688с.
- Федоров Б.Ф. Лазеры. Основы устройства и применение. - М.: ДОСААФ, 1988. - 190с.
- McKibbin L., Downie R. Treatment of Post Herpetic Neuralgia using a 904nm
(infrared) Low Incident Energy
- Laser: a Clinical Study // LLLT for Postherpetic Neuralgia, 1991. -
- OE Reports, №155 / November, 1996.
- Titov M.N., Moskvin S.V. and Priezzhev A.V. - Opimisation of the
parameters of biostimulator "Mustang" in respect to the light scattering
properties of the tissues // Paper # 2086-22 presented at SPIE's Symposium
"Biomedical Optics Europe'93", Budapest, Hungary, 1993