The action of visible light on the specialized cells of
the eye underlies sight. Nevertheless, the problem of the
possibility of action of visible light on other human and
animal cells and tissues was for a long time left unex
plored. The appearance of lasers, sources of intensive
visible and infrared radiation, gave a new impulse to this
problem (see reviews [1, 2]). Lasers became widely used
in surgery and therapy, and the question of whether vis
ible light has an effect was solved by itself. The mecha
nism of action of laser light can, nevertheless, vary in
different situations and for the most part is poorly stud
Activation of life processes under laser radiation,
often called “biostimulation”, is of most interest [3 6].
Under large doses of laser radiation, its positive action
changes, as a rule, into inhibition of vital activity process
es, which is a main hindrance to a successful application
of laser therapy and a cause of disappointment.
Nevertheless, radiation by low intensity lasers (LIL)
and light emitting diodes (LED) is widely used by physi
cal therapists and dentists (to reduce pain), dermatolo
gists (treatment of edema, eczema, and dermatitis), sur
geons (treatment of persisting ulcers, burns, “diabetic
foot”), rheumatologists (either to relieve pain or treat
chronic diseases—arthritis and arthrosis), therapeutists,
in veterinary medicine, sports medicine, and rehabilita
tion centers [1, 2, 7, 8]. According to Medline data
(search by key words laser and therapy), 1700 to 2400
papers on therapeutic application of lasers have been
published annually during the last ten years, this number
growing steadily.
Exposure to lasers as well as LED light is currently
applied in therapy. The most effective irradiation is that in
the red and near infrared range of the spectrum. The most
commonly used sources are the helium neon laser (He
Ne) (radiation at 632.8 nm), the gallium aluminum laser
(Ga Al) (630 685 nm), the helium neon arsenate laser
(He Ne As) (780 870 nm), and the gallium arsenate
laser (Ga As) (904 nm), as well as light emitting diodes
whose emission band lies in a wide region of the spectrum
(670 to 950 nm) [2]. The main reason for using the
sources radiating in the red and near infrared spectral
region is the fact that hemoglobin does not absorb in this
region and light can penetrate deep into living tissue.
Comparison of the therapeutic effects of a coherent
(LIL) and an incoherent (LED) source showed no signif
icant difference [2, 9, 10]. This is also relevant to the
action of light on the level of cells where coherent and
incoherent sources had the same effect at the same wave
lengths, intensities, and radiation times [11, 12].
What is it known about the action of laser radiation
on objects simpler than an ill human being? Consider
some well established facts.
Radiation with wavelength of 400 to 500 nm and
about 600 nm brought about accelerated cell division in
0006 2979/04/6901 0081 ©2004 MAIK “Nauka /Interperiodica”
* To whom correspondence should be addressed.
Biochemistry (Moscow), Vol. 69, No. 1, 2004, pp. 81 90. Translated from Biokhimiya, Vol. 69, No. 1, 2004, pp. 103 113.
Original Russian Text Copyright © 2004 by Vladimirov, Osipov, Klebanov.
Photobiological Principles of Therapeutic Applications
of Laser Radiation
Yu. A. Vladimirov*, A. N. Osipov, and G. I. Klebanov
Department of Biophysics, Russian State Medical University, ul. Ostrovityanova 1, Moscow 117513, Russia;
fax: (7 095) 246 4630; E mail:
Received September 30, 2003
Abstract—Laser therapy based on the stimulating and healing action of light of low intensity lasers (LIL), along with laser
surgery and photodynamic therapy, has been lately widely applied in the irradiation of human tissues in the absence of exoge
nous photosensitizers. Besides LIL, light emitting diodes are used in phototherapy (photobiostimulation) whose action, like
that of LIL, depends on the radiation wavelength, dose, and distribution of light intensity in time but, according to all avail
able data, does not depend on the coherence of radiation.
Key words: laser radiation, phagocytes, heme protein