Investigation of the influence of laser irradiation on the relative concentration of oxyhemoglobin in the blood

Transcription

1 Investigation of the influence of laser irradiation on the relative concentration of oxyhemoglobin in the blood MM. Asimov, AT. Gisbrecht*, S.A. Marnilov**, Yu.S. Plaksiy** Institute ofphysics NAS ofbelarus, F. Scaryna Ave. 68, Minsk, Belarus. *Institute ofelectronics, 72 Tzarigradsko Blvd, 1784 Sofia, Bulgaria. **Institute ofapplied problems ofphysics and biophysics NAS of Ukraine, 44 Lvivska Str. Kiev, Ukraine. ABSTRAT One of the mechanisms of influence of laser radiation on the biological tissue is photodissociation of oxyhernoglobin with releasing of molecular oxygen, thus decreasing the degree of blood oxygen saturation. The experimental study of oxygen saturation of arterial blood under laser action is based on the registration of sinai! variations of the saturation value on the background of the natural saturation oscillations. While the determination of the value of oxygen saturation allows to observe respiratory processes, the value of venous saturation allows to determine the dynamics and efficiency of the oxygen absorption in tissues, as well as the condition of venous vessels. The tissue and vein oxygen saturation have not been studied sufficiently so far. The simultaneous control of arterial and tissue saturation values will give opportunity to study the oxygen supply processes. Tile alifl5 of this work are experimental study of laser induced photodissociation of oxyheinoglobin and determination of tile dependence between the saturation value and the laser parameters. This will allow to develop new methods of control, as well as to realize a feedback during laser tiierapy. Keywords : oxyhemoglobin, laser, arterial blood, oxygen saturation, biostimulation. INTRODUTION The low energy laser (LEL) therapy llas become a routine in treating a wide range of diseases. In spite of the fact tilat the biostimulating and therapeutic effect of LEL radiation has been already well established, tile Inecllanism of this phenomenon is not yet well understood. Generally, tile biostimulating effects of LEL radiation is considered to be very complex, involving for example anti-inflanunatory, analgesic and ailti-edelnatous effects On tissues. The Illost exciting ill laser therapy is tile wound healing wllere tile process of fast epitelizatioll obviously directly connected with the stimulation of cell metabolism. Nevertileless, it is Ilot clear how laser radiation can improve the efficiency of metabolism of cells. Recently, tile new concept of tile primary lllecllanislll of biostimulation aild therapeutic effect of LEL radiation colulected witil increase of local concentration of oxygen due to photodissosiation of oxyhemoglobin in cutaneous blood vessels ilas been suggested by Asimov MM. et all 2 Using a simple optical model of tile skin,tile efficiency of interaction of laser radiation witil oxyllemoglobin in tile blood vessels at different wavelengths and layers of tissue has been investigated The results obtained in these investigations clearly demonstrate tile possibility of monitoring the local concentration of oxygen due to photodissociation of oxyhemoglobin in the cutaneous blood vessels. This phenomenon provides solid scientific basis for developing new method both diagnosis and treatment ofvarious diseases. Experimental evidence of tile suggested in 2biomedical application of laser-induced photodissociation of oxyhemoglobin for local increase of tile concentration of oxygen in tissues llas been demonstrated in 6 In experiments on animals it has been shown significant increase an efficiency of tile method of photodynamic tilerapy when additionaily applying photodissociation of oxyhemoglobin with a second laser radiation. Two wavelength laser photodynamic therapy of cancer was suggested and is actively developing. mn.asimovdragon.bas-net.by 13th International School on Quantum Electronics: Laser Physics and Applications, P. A. Atanasov, S. V. Gateva, L. A. Avramov, A. A. Serafetinides, eds., Proc. of SPIE Vol (SPIE, Bellingham, WA, 2005) X/05/$15 doi: /

2 The effect of local changes of arterial blood saturation during laser irradiation has been described by Marnilov S.A. et all in. The decreases in saturation clearly prove the proposed concept of laser-induced photodissociation 2 of oxyheinoglobin and local increases in the concentration of free oxygen that enhances the metabolism of cells. In this report the result of evaluation of the experimental study of laser induced photodissociation of oxyheinoglobin is presented. Special attention is paid to investigation of the dependence between the saturation values, laser parameters and optics of human skin. MATERIALS AND METHOD The experimental study of changes in saturation of arterial blood caused by laser-induced photodissociation of oxyheinoglobin is based on registration of the variations of its value on the background of natural saturation oscillations. The specialized pulse-oxyineter monitor was used for recording high accuracy photoplethysmograrns and detailed numerical signal processing has been applied. This method was developed for registration of small changes of arterial blood saturation for one heart pulse with error not more than 0.3 % The measurements were carried out in transmitted light with the pulse oxyineter sensor, which consists of two lightemitting diodes (660 mn and 900 nm) and a photodiode set on the opposite side of the finger. The sensor was placed on the first of two phalanxes of the finger and the measuring elements were in the region of the first phalanx. In the iriajority of experiments the laser radiation was guided to the region of the third phalanx of the finger. The effect of laser radiation on the arterial blood oxygen saturation was observed at different wavelengths. We have used He-Ne laser radiation with a wavelength of 632 urn, which is inosily applied in medical practice, and a semiconductor laser with a wavelength of 653 urn. The diameter of the laser spots on the skin was about 7-8 mm. RESULTS AND DISUSSION The irradiation of the third phalanx of the finger at both wavelengths decreases the value of saturation when increasing the laser radiation power. In Fig. 1 the change in arterial blood oxygen saturation in dependence on the power of the He- Ne laser is shown. I,4 V V I,2-1,0-0,8-0, The He-Ne laser power (mw) Fig.1. hanges in arterial blood oxygen saturation on dependence of the power of He-Ne laser 410 Proc. of SPIE Vol. 5830

3 There is a dependence between the degree of decrease of the measured value of saturation and the distance between the points of irradiation. At irradiation of the second phalanx of the finger (P=14 rnw) the change of saturation is about 1,8-2% and the effect becomes weaker (1,4%) when we shift irradiation zone o the third phalanx. There are no clurnges at all when the irradiation is shifted far from the area where the finger feeding artery passed. These results clearly demonstrate that the observed effect is local and prove the effect of laser induced photodissociation of oxyheinoglobin in the blood capillary vessels. The diagram of arterial blood saturation changes during the laser irradiation is shown in Fig. 2. As it is seen from the diagram, the changes of saturation take place a few seconds after starting the illumination of the zone and the level of. saturation does not depend on the irradiation time. The effect disappeares with closing the illumination and the saturation restores up to its initial value. 9?. MIUV\/\P\ JJV\JiV [VW\AtL. I I I ' I I I ' I 1i I I I I ' I I 20 O O O 100 1O 1O 1O O Time (ec) Fig. 2. hanges of arterial blood oxygen saturation during the laser radiation The spectral dependence of the changes of arterial blood saturation at different wavelengths of laser radiation has been investigated. In Fig.3 the action spectra of oxyhemoglobin in cutaneous blood vessels in a depth of 2 mm are presented, together with the integral spectra calculated for light penetration to layers of skin in the range of integration from 0.1 mm to 5 mm. These spectra qualitatively demonstrate the probable efficiency of changes in blood oxygen saturation one could expect at illumination with different wavelengths of laser radiation. It should be noted that the optical properties of real skin vary and the quantitative data will be different too. Proc. of SPIE Vol

4 o 012 I 0, ,010 0,002 0, JVcrvelerigth [nin] Fig.3 Absorption spectra of oxyheinoglobin cutaneous blood vessels in the depth of 2 mm curve 1 Integral spectra calculated for whole depth curve 2 Experimental study of the dependence of the saturation on tile wavelength of radiation was carried out, using different lasers. Thus, in tile yellow and green regions of the action spectra of oxyhernoglobin we have used the radiation of the u-vapor laser at two wavelengths:?= mu and nm. The decrease in saturation recorded at a power of radiation about 25 rnw is %. Tile changes of saturation in the case of illumination in the JR spectral region with a pulsed laser at 2= 950 nm (peak power 10 W, pulse duration 100 ns) with repetition rate from 50 to 2500 Hz were very small. There are 110 changes in saturation for illuiriination in the blue range of the spectrum with radiation of Ne-d laser at 2= 446 mm and power of 10 rnw. It is due to tile screening effect of tile skin, whicil limits the spectral range oflight penetration deep into tissue. Experimental investigation of tile cilanges in blood oxygen saturation were carried out with white (noncoherent) ligilt too. As expected ( from general physical consideration) photodissociation of oxyhernogiobin takes place and at light power 20 mw the cllanges of saturation reach 0.8 %. Thus, tile induced pilotodissociation of oxyhernoglobin in vivo takes place with illuillillation of tile arterial blood with laser radiatioll, as well as with white light. ONLUSION Tile obtained results give an experimental confirmation of our consideration of tile primary Inecilamsin of biostirnulation tilat tile therapeutic effect of low energy laser radiation is based on local increasing of tile concentration of oxygen due to the induced photodissociation of oxyhernoglobin in the cutaneous blood vessels of ilurnan skin. This phenomenon allows us to develop an objective method to control the efficiency of treatment by laser phototherapy. Tilis make possible in ciinicai application to tune tile parameters of the laser radiation to optimal wavelength, power and exposition time in dependence Ofl tile optical cilaracteristics of tile patient skin. The obtained results also SilOw us the way of increasmg tile efficiency of biostimulation and the therapeutic effect of low energy laser radiation based on its combination with the method of oxygen ilyperventilatlon therapy. 412 Proc. of SPIE Vol. 5830

5 Another important conclusion can also be drawn from the obtained results. In the interpretation of the biostimulating and healing effect of laser radiation the phenomenon of induced photodissociation of blood oxyhernoglobin should be taken into account. REFERENES 1.Takas S., Stojanovich S. Diagnostic and biostirnulating lasers. Med. Pregl. Vol. 5 1.N 5-6. P Asirnov MM., Asiinov R.M., Rubinov AN. Investigation of the efficiency of laser action on hemoglobin and oxyhernoglobin in the skin blood vessels. SPIE Proceedings. Laser -Tissue Interaction lx. 1. San Jose USA. Vol Pp Anderson R.R., Perrisli J.A. The optics ofliuman skin. J. Invest. Derinatol. Vol. 77. N 1. P Asirnov MM., Asirnov R.M., Rubinov AN. Action spectra of laser radiation on hemoglobin of skin blood vessels. Journal ofapplied Spectroscopy. V.65. N 6. P Asimov M., Asirnov R., Mirshahi M., Gisbrecht A. Effect of laser induced photodissosiation of oxyhemoglobin on biomedical processes. 1 ith International School on Quantum Electronics: Laser physics and Applications, Proceedings of SPIE Vol P Dzhagarov B.M., Zhavrid E.A., Istornin Yu.P., halov V.N. Two color laser photodynarnic therapy of cancer. Journal ofapplied Spectroscopy. V.68. N 2. P Virko Yu. B., Kravchenko VI., Marnilov S.A., Plaksiy Y.S. Effect of low intensity laser radiation on arterial blood oxygen saturation. Proc. ofiv International onfon Laser Physics and Spectroscopy. Grodno. Belarus P Bakaj Ed. A., Kravchenko VI., Marnilov S.A., Minov O.N., Plaksiy Yu. S., Rikberg A.B. "Multichannel optical measurements for in vivo determination tissue indices". Optical & Biological Engineering & omputing. Vol.3 5. Supplement Pan 1. P V.I. Kravcheiiko, S.A. Mamilov, ON. Minov, Yu. S. Plaksiy. "Investigations of correlation of optical signals during measuring an arterial blood oxygen saturation", The Ukrainian J. of Medical Technique and Tecimolog. V. ip.59-6l 1999 Proc. of SPIE Vol