Patent Publication Number: US-2019168024-A1

Title: Diode Laser Irradiation System for Biological Tissue Stimulation

Description:
TECHNICAL FIELD 
     The present invention relates generally to the treatment of living biological tissue by optical irradiation, and in particular to a system for stimulating living bone, nerve and soft tissue by diode laser irradiation. 
    
    
     BACKGROUND OF THE INVENTION 
     Various non-surgical means have been employed in the therapeutic treatment of living tissue. Such techniques have included the application of ultrasonic energy, electrical stimulation, high frequency stimulation by diathermy, X-rays and microwave irradiation. While these techniques have shown some therapeutic benefit, their use has been somewhat limited because they generate excessive thermal energy which can damage tissue. Consequently, the energy levels associated with therapeutic treatments involving diathermy, X-ray, microwave and electrical stimulation have been limited to such low levels that little or no benefit has been obtained. Moreover, the dosage or exposure to microwaves and X-ray radiation must be carefully controlled to avoid causing health problems related to the radiation they generate. Ultrasonic energy is non-preferentially absorbed and affects all of the tissue surrounding the area to which it is directed. 
     Optical energy generated by lasers has been used for various medical and surgical purposes because laser light, as a result of its monochromatic and coherent nature, can be selectively absorbed by living tissue. The absorption of the optical energy from laser light depends upon certain characteristics of the wavelength of the light and properties of the irradiated tissue, including reflectivity, absorption coefficient, scattering coefficient, thermal conductivity, and thermal diffusion constant. The reflectivity, absorption coefficient, and scattering coefficient are dependent upon the wavelength of the optical radiation. The absorption coefficient is known to depend upon such factors as interband transition, free electron absorption, grid absorption (photon absorption), and impurity absorption, which are also dependent upon the wavelength of the optical radiation. 
     In living tissue, water is a predominant component and has, in the infrared portion of the electromagnetic spectrum, an absorption band determined by the vibration of water molecules. In the visible portion of the spectrum, there exists absorption due to the presence of hemoglobin. Further, the scattering coefficient in living tissue is a dominant factor. 
     Thus, for a given tissue type, the laser light may propagate through the tissue substantially unattenuated, or may be almost entirely absorbed. The extent to which the tissue is heated and ultimately destroyed depends on the extent to which it absorbs the optical energy. It is generally preferred that the laser light be essentially transmissive through tissues which are not to be affected, and absorbed by tissues which are to be affected. For example, when applying laser radiation to a region of tissue permeated with water or blood, it is desired that the optical energy not be absorbed by the water or blood, thereby permitting the laser energy to be directed specifically to the tissue to be treated. Another advantage of laser treatment is that the optical energy can be delivered to the treatment tissues in a precise, well-defined location and at predetermined, limited energy levels. 
     Ruby and argon lasers are known to emit optical energy in the visible portion of the electromagnetic spectrum, and have been used successfully in the field of ophthalmology to reattach retinas to the underlying choroidea and to treat glaucoma by perforating anterior portions of the eye to relieve interoccular pressure. The ruby laser energy has a wavelength of 694 nanometers (nm) and is in the red portion of the visible spectrum. The argon laser emits energy at 488 nm and 515 nm and thus appears in the blue-green portion of the visible spectrum. The ruby and argon laser beams are minimally absorbed by water, but are intensely absorbed by blood chromogen hemoglobin. Thus, the ruby and argon laser energy is poorly absorbed by non-pigmented tissue such as the cornea, lens and vitreous humor of the eye, but is absorbed very well by the pigmented retina where it can then exert a thermal effect. 
     Another type of laser which has been adapted for surgical use is the carbon dioxide (CO 2 ) gas laser which emits an optical beam which is absorbed very well by water. The wavelength of the CO 2 laser is 10,600 nm and therefore lies in the invisible, far infrared region of the electromagnetic spectrum, and is absorbed independently of tissue color by all soft tissues having a high water content. Thus, the CO 2  laser makes an excellent surgical scalpel and vaporizer. Since it is completely absorbed, its depth of penetration is shallow and can be precisely controlled with respect to the surface of the tissue being treated. The CO 2  laser is thus well-suited for use in various surgical procedures in which it is necessary to vaporize or coagulate neutral tissue with minimal thermal damage to nearby tissues. 
     Another laser in widespread use is the neodymium doped yttrium-aluminum-garnet (Nd:YAG) laser. The Nd:YAG laser has a predominant mode of operation at a wavelength of 1064 nm in the near infrared region of the electromagnetic spectrum. The Nd:YAG optical emission is absorbed to a greater extent by blood than by water making it useful for coagulating large, bleeding vessels. The Nd:YAG laser has been transmitted through endoscopes for treatment of a variety of gastrointestinal bleeding lesions, such as esophageal varices, peptic ulcers, and arteriovenous anomalies. 
     The foregoing applications of laser energy are thus well-suited for use as a surgical scalpel and in situations where high energy thermal effects are desired, such as tissue vaporization, tissue cauterization, and coagulation. 
     Although the foregoing laser systems perform well, they commonly generate large quantities of heat and require a number of lenses and mirrors to properly direct the laser light and, accordingly, are relatively large, unwieldy, and expensive. These problems are somewhat alleviated in some systems by locating a source of laser light distal from a region of tissue to be treated and providing fiber optic cable for carrying light generated from the source to the tissue region, thereby obviating the need for a laser light source proximal to the tissue region. Such systems, however, are still relatively large and unwieldy and, furthermore, are much more expensive to manufacture than a system which does not utilize fiber optic cable. Moreover, the foregoing systems generate thermal effects which can damage living tissue, rather then provide therapeutic treatment to the tissue. 
     Therefore, what is needed is a system and method for economically stimulating soft, living tissue with laser energy without damaging the tissue from the thermal effects of the laser energy. 
     SUMMARY OF THE INVENTION 
     The present invention, accordingly, provides a system and a method that retains all of the advantages of the foregoing systems while reducing the size and cost of the system. To this end, a system for treating biological tissue without exposing the tissue to damaging thermal effects, comprises a wand which houses an Indium Gallium Arsenide (In:GaAs) diode laser configured for generating coherent optical energy radiation having a wavelength in the range of the near infrared region of the electromagnetic spectrum at a power output in the range of from about 100 milliwatts (mw) to about 1000 mw. The coherent optical energy radiation is focused on the treatment area to achieve a rate of absorption and conversion to heat in the irradiated tissue in the range between a minimum rate sufficient to elevate the average temperature of the irradiated tissue to a level above the basal body temperature of the living subject, and a maximum rate which is less than the rate at which the irradiated tissue is converted into a collagenous substance. 
     The invention provides a wand that includes three diode lasers at one end in a triangular arrangement. The lasers generate laser light having a wavelength in the range of 1064 nm-10,000 nm at a power output level of less than 1000 mw. The preferred embodiments the diode lasers generate laser light at 1350 nm, 1550 nm, or 3150 nm. A first set of metallic cooling fins surrounds the lasers at the end of the wand for transferring heat to the surrounding air. A second set of cooling fins is connected to the conductive bar at the opposite end. 
     In one embodiment, the system also provides electrostimulation therapy concurrently with laser irradiation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  shows a schematic diagram of a diode laser irradiation system of the present invention; 
         FIG. 2  shows a cross-section view of a wand used in the system of  FIG. 1 ; 
         FIG. 3A  shows an enlarged, elevational view of a laser resonator used in the wand of  FIG. 2 ; 
         FIG. 3B  shows an enlarged, end view of the laser resonator used in the wand of  FIG. 3A ; 
         FIG. 4A  shows a side, cross-section view of an alternate laser wand in accordance with the present invention; 
         FIG. 4B  shows a front end view of the alternate laser wand shown in  FIG. 4A ; and 
         FIG. 5  is a process flow showing the operation of the biostimulation system in accordance with an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Referring to  FIG. 1 , the reference numeral  10  refers generally to the diode laser irradiation system of the present invention which includes a biostimulation control unit  12  for controlling the operation of a hand-operated probe, i.e., a laser treatment wand  14 , electrically connected to the control unit via a coaxial cable  16 . As will be described in detail below, the wand  14  houses a diode laser capable of emitting low level reactive laser light for use in tissue irradiation therapy. 
     The control unit  12  receives power through a power supply line  18  adapted for connection to a conventional 120-volt power outlet. A ground piece  19  is connected to the control unit  12  and is held by a patient receiving the tissue irradiation therapy to provide an electrical ground for safety purposes. An on/off switch  20  is connected in series with the line  18  for controlling the flow of power through the line. A foot pedal  22  is connected to the control unit  12  and is depressible for activating the generation and emission of laser light from the wand  14 . Activation may alternatively, or additionally, be provided using a switch on the wand  14 . 
     The control unit  12  includes laser setting controls  24  and corresponding setting displays  26 . The setting controls  24  are utilized to select operational parameters of the control unit  12  to effect the rate of absorption and conversion to heat of tissue irradiated by the wand  14 , according to desired treatment protocols. Generally, the treatment protocols provide for a rate of absorption and conversion to heat in the irradiated tissue in a range between a minimum rate sufficient to elevate the average temperature of the irradiated tissue to a level above the basal body temperature of the subject and a maximum rate which is less than the rate at which the irradiated tissue is converted to a collagenous substance. The treatment protocols vary time, power, and pulse/continuous mode parameters in order to achieve the desired therapeutic effects. 
     The setting controls  24  include a treatment time control  28 , a power control  30 , and a pulse/continuous mode control  32 . Adjustments in treatment time, power and pulse/continuous mode operation of the wand  14  utilizing the controls  28 - 32  make possible improved therapeutic effects based upon the aforementioned treatment protocols involving one or more of these parameters. Also, an impedance control  34  is provided adjusting an impedance measurment of the tissue to a baseline value, according to skin resistance, as discussed further below, whereby improvements in tissue condition may be monitored. It is understood that, according to the specific embodiment of the control unit  12 , the setting controls  24  may include any combination of one or more of the controls  28 - 34 . 
     The setting displays  26  include a time display  36 , a power display  38 , a pulse display  40  and an impedance display  42 . In one embodiment, each of the displays  26  are light emitting diode (LED) displays such that the corresponding setting controls  24  can be operated to increment or decrement the settings, which are then indicated on the displays. The setting displays  26  may be in the form of a selectable touch screen. A programmed settings control  44  is used to save setting selections and then automatically recall them for convenience, using one or more buttons  44   a - 44   c,  for example. 
     The time control  28  adjusts the time that laser light is emitted from the wand  14  from 0.01 to 9.99 minutes in 0.01 minute intervals, as indicated on the time display  36 . The time display  36  includes a countdown display  36   a  and an accumulated display  36   b . Once the time control  28  is set, the countdown display  36   a  indicates the setting so that as the wand  14  is operated the time is decremented to zero. The accumulated time display  36   b  increments from zero (or any other reset value) as the wand  14  is operated so that the total treatment time is displayed. The time display  36  takes into account the pulsed or continuous mode operation of the system  10 . 
     The power control  30  adjusts the power dissipation level of the laser light from the wand  14  in a range from zero to 1000 mw, with typical operation ranging from about 500 mw to 1000 mw. The pulse/continuous mode control  32  sets the system  10  to generate laser light energy from the wand  14  either continuously or as a series of pulses. The control  32  may include, for example, a pulse duration rheostat (not shown) for adjusting the pulse-on or pulse-off time of the wand  14 . In one implementation, the pulses-per-second (PPS) is set in a range from zero to 9995, adjustable in 5 step increments. The PPS setting is displayed on a PPS display  40   a.  The pulse duration may alternatively, or additionally, be displayed indicating the duty cycle of pulses ranging from 5 to 99 (e.g., 5 meaning that the laser is “on” 5% of the time). A continuous mode display  40   b  is activated when the system  10  is being operated in the continuous wattage (CW) mode of operation. 
     An audio volume control  46  is provided for generating an audible warning tone from a speaker  48  when laser light is being generated. Thus, for example, the tone may be pulsed when the system is operating in the pulse mode of operation. 
     The impedance control  34  is a sensitivity setting that is calibrated and set, according to the tissue skin resistance, to a baseline value which is then indicated on the impedance display  42 . As therapy progresses the impedance readout on the display  42  changes (i.e. it decreases) thereby indicating progress of treatment. 
     A calibration port  49  is utilized to verify laser performance by placing the wand  14  in front of the port and operating the system  10 . The port  49  determines whether the system  10  is operating within calibration specifications and automatically adjusts the system parameters. 
     In addition to the laser control elements, the system  10  also includes controls and displays for providing electronic stimulation concurrently with laser irradiation. The electronic stimulation setting controls  224  include a treatment time control  228 , a current control  230 , and a frequency control  232 . It is understood that, according to the specific embodiment of the control unit  12 , the electrostimulation controls  224  may include any combination of one or more of the controls  228 - 232 . 
     Electrostimulation is provided through one or more contact pads  250  that are placed in contact with the patient&#39;s skin. These may be self-adhesive pads or help in place by straps. In the embodiment shown in  FIG. 1 , the electrostimuation pad(s) are connected to the control system  12  by the same coaxial cable  16  as the laser wand  14 . In an alternate embodiment (not shown), the electrostimulation pad(s) are connected to the control unit  12  separately from the wand  14 . In a preferred embodiment, electrode wires for up to four pads are connected to control unit  12 . 
     The electrostimulation setting displays  226  include a time display  236 , a current display  238 , and a frequency display  240 . In one embodiment, each of the displays  226  are light emitting diode (LED) displays such that the corresponding setting controls  224  can be operated to increment or decrement the settings, which are then indicated on the displays. As with the laser setting displays  26 , electrostimulation displays  226  may be in the form of a selectable touch screen. In a preferred embodiment, the laser setting displays  26  and electrostimuation setting displays  226  share a common selectable touch screen for user input. 
     The time control  228  adjusts the time that current is provided through the contact pad  250  in minutes and seconds, as indicated on the time display  236 . The time display  236  can be a countdown display or an accumulated display. 
     The current control  230  adjusts the level of current passing through the contact pad  250  in a range of 25-500 microamperes (μA), which is displayed on current display  238 . The frequency control  232  adjusts the pulse frequency of the current passing through the contact pad  250  in a range of 4001-4150 Hz, which is displayed on frequency display  240 . 
     While not shown, the control unit  12  includes digital and analog electronic circuitry for implementing the foregoing features. The details of the electronic circuitry necessary to implement these features will be readily understood by one of ordinary skill in the art in conjunction with the present disclosure and therefore will not be described in further detail. 
     Referring to  FIG. 2 , the wand  14 , sized to be easily manipulated by the user, includes a heat-conductive, metal bar  50 . The bar  50  is hollow along its central axis and is threaded on its interior at a first end for receiving a laser resonator  52 , described further below with reference to  FIGS. 3A and 3B . Wiring  51  extends from the resonator  52  through the hollow axis of the bar  50  for connection to the coaxial cable  16  ( FIG. 1 ). In an embodiment the bar  50  is copper or steel and thus conducts electricity for providing a ground connection for the resonator  52  to the cable  16 . 
     A glass noryl sleeve  54  is placed over the bar  50  for purposes of electrical and thermal insulation. A screw  55  extending through the sleeve  54  anchors the sleeve to the bar  50 . As shown, the resonator  52  is recessed slightly within the sleeve  54 . An impedance oring  56 , formed of a conductive metal, is press-fitted into the end of the sleeve  54  so that when the wand  14  makes contact with tissue, the ring  56  touches the tissue. The ring  56  is electrically connected through the wand  14  to the unit  12 . The ring  56  measures impedance by measuring angular DC resistance with an insulator ohmmeter, for example, of the tissue being irradiated by the wand  14  which is then displayed as impedance on the display  42 . Any other suitable impedance measurement circuit may be utilized, as will be apparent to one skilled in the art. Measurements of impedance are useful in therapy to determine whether healing has occurred. For example, a baseline measurement of impedance provides an objective value of comparison wherein as the tissue heals, a lower impedance approaching the baseline is observed. The impedance value read can also be used to determine the amount of milliwattage and time of treatment appropriate for the patient. 
     A feedback sensor  57  is located in the end of the sleeve  54  for measuring the output of the resonator  52 . While not shown, the sensor  57  is connected electronically to the control unit  12  and to a feedback circuit within the control unit. A small percentage of the diode laser light from the resonator  52  is thus detected by the sensor  57  and channeled into the feedback circuit of the control unit  12  to measure and control performance of the resonator. Out-of-specification temperature, power, pulse frequency or duration is thus corrected or the system  10  is automatically turned off. 
     Multiple metallic fins  58  are placed over the end of the bar  50  and are separated and held in place by spacers  60  press-fitted over the bar  50 . The fins  58  act as a heat sink to absorb heat from the laser through the bar  50  and dissipate it into the surrounding air. The spacers  60  placed between each fin  58  enable air to flow between the fins, thereby providing for increased heat transfer from the wand  14 . 
     A casing  62  fits over the sleeve  54  and serves as a hand grip and structure to support a switch  64  and light  66 . The switch  64  is used to actuate the wand  14  by the operator wherein the switch must be depressed for the wand to operate. The switch  64  is wired in a suitable manner to the control unit  12  and is used either alone or in conjunction with the foot pedal  22 . The light  66  is illuminated when the wand  14  is in operation. 
     As shown in  FIG. 3A , the laser resonator  52  includes a housing  68  having threads  68   a  configured for matingly engaging the threaded portion of the bar  50  in its first end. An Indium-doped Gallium Arsenide (In:GaAs) semiconductor diode  70  is centrally positioned in the housing  68  facing in a direction outwardly from the housing  68 , and is electrically connected for receiving electric current through the threads  68   a  and an electrode  72  connected to the wiring  51  that extends longitudinally through the hollow interior of the tube  50  ( FIG. 2 ). The amount of Indium with which the Gallium Arsenide is doped in the diode  70  is an amount appropriate so that the diode  70 , when electrically activated, generates, in the direction outwardly from the housing  68 , low level reactive laser light having a fundamental wavelength ranging from, depending upon the implementation, about 1064 +/−20 nm to 10,000 +/−20 nm in the infrared region of the electromagnetic spectrum. Other types of diode semiconductor lasers may also be used to produce the foregoing wavelengths, e.g., Helium Neon, GaAs or the like. 
     The operating characteristics of the diode  70  are an output power level of 100-1000 mw, a center fundamental wavelength of 1064 +/−20 nm to 10,000 +/−20 nm, with a spectral width of about 5 nm, a forward current of about 1500 milliamps, and a forward voltage of about 5 volts at the maximum current. Recent research has revealed that within the wavelength range listed above there are in fact optimal “pockets” in which specific wavelengths are particularly well absorbed by biological tissue, achieving maximum benefit. In preferred embodiments of the invention, the diode  70  generates laser light at a fundamental wavelength of 1350 nm, 1550 nm, or 315 nm, depending on the specific implementation. In an embodiment of the invention intended for human application, the preferred laser power level is 500 mw. For veterinary applications, the preferred laser power is 155 mw. 
     As shown in  FIGS. 3A and 3B , a lens  74  is positioned at one end of the housing  68  in the path of the generated laser light for focusing the light onto tissue treatment areas of, for example, 0.5 mm 2  to 2 mm 2 , and to produce in the treatment areas an energy density in the range of from about 0.01 to about 0.15 joules/mm 2 . The lens  74  may be adjusted to determine depth and area of absorption. 
       FIG. 4A  shows a side, cross-section view of an alternate in wand in accordance with the present invention.  FIG. 4B  shows a front-end view of the alternate laser wand. This embodiment includes three resonators  152   a,    152   b,  and  152   c,  arranged in a triangular configuration and each containing a laser diode  170   a,    170   b,  and  170   c,  respectively. Diodes  170   a - 170   c  may be In:GaAs, Ga:As, or any of the diode types described above. 
     The triangular three-diode configuration of wand  140  allows additional treatment options not possible with the single-diode wand  14 . The single-diode wand  14  is best suited for pinpoint application of laser light to areas such as nerve points, joints, and the spine. The three-diode wand  140  allows simultaneous laser irradiation of a broader area of tissue. The spacing of the resonators  152   a - 152   c  also allows the diodes to work around certain body structures. For example, whereas wand  14  would be used for laser irradiation of the spine, wand  140  would be used to irradiate the paraspinal muscles that flank the spine. 
     Wand  140  includes an additional set of metallic cooling fins  175  surrounding the resonators diodes at the terminal end of the wand. The additional cooling fins are used due to the increased heat produced by the three diodes  170   a - 170   c.  This increased heat is not only due to the increased number of diodes and resonators in wand  140  versus wand  14  but also the density of heat generated within a given volume. Whereas the laser resonator  52  in wand  14  is surrounded by the exterior walls of the wand, the resonators  152   a - 152   c  in wand  140  partially transfer heat toward the interior of the end unit. This creates local heat that cannot be adequately dissipated by thermal conduction through rod  150  to the metallic fins  158  at the far end of the wand. The additional metallic fins  175  surrounding the resonators  152   a - 152   c  provide adequate local heat dissipation to prevent thermal damage to the tissue that cannot be achieved by relying solely on the fins  158  at the far end of the wand. A plastic cover plate  180  provides additional thermal protection of the tissue. 
     It should be noted that  FIGS. 2, 4A and 4B  are for illustrative purposes and not drawn to scale. 
     In operation, the switch  20  is closed (i.e., turned on) to power up the control unit  12 , at which time the displays becomes illuminated, thereby indicating that the control unit is receiving power. The time control  28  is set for specifying a desired duration of time for laser treatment, which time is displayed on the countdown display  36   a.  The mode control  34  is set for specifying whether the laser light is to be generated in the continuous or the pulsed mode. If the pulsed mode is selected, then the duration of the pulse on-time/off-time is specified and the pulses-per-second (and the pulse duty cycle if appropriate) is displayed on the PPS display  40   a.  If the continuous mode instead is chosen, the continuous mode display  40   b  is illuminated. It can be appreciated that the mode and the pulse time-on and time-off settings affect the intensity of the treatment provided. The amount of power is further set by the power control  30 , and displayed on the power display  38 . It can be appreciated that the power, duration and pulse intensity of treatment is thus selectable by the unit  12  and is to be determined by treatment protocols relating to the character of the tissue to be treated, the depth of penetration desired, the acuteness of the injury, and the condition of the patient. The audio volume control  46  can be adjusted to control the volume of the tone generated from the speaker  48 . The tissue impedance display  42  indicates an impedance value for tissue in contact with it and can be calibrated to a baseline set for the patient by applying the wand  14  to surrounding non-damaged tissue and then when the wand  14  is applied to the damaged tissue, an impedance value (much higher than the baseline) will be indicated and hopefully reduced over time, through treatment, to the baseline value. 
     After the time, power, and mode (continuous wattage or pulsed at a selected intensity) selections are made, the wand  14  may be directed into the calibration port  49  to verify the accuracy of the system. The wand  14  may then be applied to patient tissue for therapy, The foot pedal  22  and/or the switch  64  may be depressed to cause therapeutic laser light energy to be generated from the wand  14 . As an indication of that laser light energy is being generated, an audible tone is generated from the speaker  32 . 
     The generated laser optical energy is applied to regions of the body where decreased muscle spasms, increased circulation, decreased pain, or enhanced tissue healing is desired. The surface of the tissue in the region to be treated is demarcated to define an array of grid treatment points, each of which points identifies the location of an aforementioned small treatment area. Each small treatment area is irradiated with the laser beam light to produce the desired therapeutic effect. Because laser light is coherent, a variable energy density of the light of from about 0.01 to 0.15 joules/mm 2  is obtained as the light passes through the lens  74  and converges onto each of the small treatment areas. The energy of the optical radiation is controlled by the power control  30  and applied (for durations such as 1 minute to 3 minutes, continuous wattage or pulsed, for example) as determined by treatment protocols, to cause the amount of optical energy absorbed and converted to heat to be within a range bounded by a minimum absorption rate sufficient to elevate the average temperature of the irradiated tissue to a level which is above the basal body temperature, but which is less than the absorption rate at which tissue is converted into a collagenous substance. The laser beam wavelength, spot or beam size, power dissipation level, and time exposure are thus carefully controlled to produce in the irradiated tissue a noticeable warming effect, which is also limited to avoid damaging the tissue from thermal effects. 
     The present invention has several advantages. For example, by using an In:GaAs diode laser to generate the laser beam energy, the laser source can be made sufficiently small to fit within the hand-held wands  14  and  140 , thereby obviating the need for a larger, more expensive laser source and the fiber optic cable necessary to carry the laser energy to the treatment tissue. The In:GaAs diode laser can also produce greater laser energy at a higher power dissipation level than lasers of comparable size. Furthermore, construction of the wands  14  and  140  including the fins  58 ,  158  and  175  provides for the dissipation from the wand of the heat generated by the laser source. 
     A further advantage is that therapeutic treatment by the foregoing low level reactive laser system has been shown to reduce pain in soft tissue, reduce inflammation, and enhance healing of damaged tissue by the stimulation of microcirculation, without subjecting the living tissue to damaging thermal effects. This phenomenon is due to certain physiological mechanisms in the tissue and at the cellular level that occur when the above process is used. In the evaluation of the microcirculatory system, for example, it has been demonstrated that the blood vessel walls possess photosensitivity. When the blood vessel walls are exposed to laser irradiation as set forth above, the tonus is inhibited in smooth myocytes, thus increasing the blood flow in the capillaries. Other effects which have been observed are: peripheral capillaries neovascularization, reduction of blood platelet aggregation, reduction of O 2  from the triplet to the singlet form which allows for greater oxygenation of the tissue, reduction of buffer substance concentration in the blood, stabilization of the indices of erythrocyte deformation, reduction of products of perioxidized lipid oxygenation of the blood. Other effects which have been observed are increased index of antithrombin activity, stimulation of the enzymes of the antioxidant system such as superoxide dismutase and catalase. An increase in the venous and lymph and outflow from the irradiated region has been observed. The tissue permeability in the area is substantially enhanced. This assists in the immediate reduction of edema and hematoma concentrations in the tissue. At the cellular level, the mitochondria have also been noted to produce increased amounts of ADP with subsequent increase in ATP. There also appears to be an increased stimulation of the calcium and sodium pumps at the tissue membrane at the cellular level. 
     At the neuronal level, the following effects have been observed as a result of the foregoing therapeutic treatment. First, there is an increased action potential of crushed and intact nerves. The blood supply and the number of axons is increased in the irradiated area. Inhibition of scar tissue is noticed when tissue is lazed. There is an immediate increase in the membrane permeability of the nerve. Long term changes in the permeability of calcium and potassium ions through the nerve for at least 120 days have been observed. The RNA and subsequent DNA production is enhanced. Singlet O 2  is produced which is an important factor in cell regeneration. Pathological degeneration with nerve injury is changed to regeneration. Both astrocytes and oligodedrocytes are stimulated which causes an increased production of peripheral nerve axons and myelin. 
     Phagocytosis of the blood cells is increased, thereby substantially reducing infection. There also appears to be a significant anti-inflammatory phenomena which provides a decrease in the inflammation of tendons, nerves, bursae in the joints, while at the same time yielding a strengthening of collagen. There is also an effect on the significant increase of granulation tissue in the closure of open wounds under limited circulation conditions. 
     Analgesia of the tissue has been observed in connection with a complex series of actions at the tissue level. At the local level, there is a reduction of inflammation, causing a reabsorption of exudates. Enkephalins and endorphins are recruited to modulate the pain production both at the spinal cord level and in the brain. The serotnogenic pathway is also recruited. While it is not completely understood, it is believed that the irradiation of the tissue causes the return of an energy balance at the cellular level which is the reason for the reduction of pain. 
     It is understood that several variations may be made in the foregoing without departing from the scope of the invention. For example, any number of fins  58  may be utilized as long they dissipate sufficient heat from the wand  14  so that the user may manipulate the wand without getting burned. The setting controls  24  may be used individually or in combination and the information displayed on the displays  26  may vary. Other diode laser structures may be utilized to produce the desired effects. 
       FIG. 5  is a process flow showing the operation of the biostimulation system in accordance with an embodiment of the invention. The process begins by selecting laser or electrotherapy (step  501 ). If laser therapy is selected the operating parameters are then selected, beginning by setting the laser treatment time (step  502 ). Next, laser power level is set (step  503 ). It should be noted that the steps of setting the treatment time and power level do not have to occur in the sequence shown in  FIG. 5 . After the treatment time and power level are set, the laser is calibrated (step  504 ). The user also has the option to select simultaneous electronic stimulation therapy to be applied at the same time as the laser irradiation (step  505 ). 
     If electrotherapy is selected at either step  501  or step  505 , the treatment time for the electrotherapy is (step  506 ). Next the current frequency is selected (step  507 ) and then the current strength (step  508 ). It should be noted that the steps of setting the treatment time, frequency, and current level do not have to occur in the sequence shown in  FIG. 5 . 
     After the parameters for the laser treatment and/or electrotherapy are set the treatment begins (step  509 ). The timing circuitry checks the time remaining at regular intervals (step  510 ) and continues the irradiation and/or electrostimulation until the programmed time of treatment has elapsed. 
     The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. It will be understood by one of ordinary skill in the art that numerous variations will be possible to the disclosed embodiments without going outside the scope of the invention as disclosed in the claims.