good morning everyone thank you for joining us my name is dr.

 Lawrence owner I am the clinical educator and laser safety officer for Kay laser Australia our organised workshop clinical training and evening seminars with the surgical cosmetic & therapeutic lasers of care later in this presentation we will focus on thier particular application we will review the latest knowledge of the mechanism as well as the latest laser technology involved and how it influences the clinical results for many years many had doubts about the therapeutic effect of laser therapy clinical result were too inconsistent and not always reproducible so why nowadays more and more universities Hospital and Clinics are equipped with therapeutic lasers well it's because like any area of science leather therapy technology has changed over the years first in research better tools are now available to identify and quantify the cellular and biological effect of laser therapy a better knowledge of the mechanism of photobiomodulation means the practitioner can choose better settings and dosage secondly the laser technology itself it is now much more advanced and complex than decades ago and it allows more photons absorptions even in deeper structures yet safely before 2014 there were so many contradictions between publications it was very difficult to compare these studies because there were many missing settings in the publications for example some study would mention the wavelengths used but not the power offerings use different names different laser technology all the same dosage would be used to target tissues at different depths imagine the confusion to compare and progress scientists needed to use the same vocabulary and indicate every parameters and settings used during their experiment these standardization occurred in 2014-2015 by adopting the medical terminology of photo bio modulation for tuba modulation or PBM in short refers to the cellular effect triggered by red and near-infrared light on living tissues it is not related to the thermal defect so more than just the word it is now possible to compare studies and learn from them so if you add together the knowledge of the mechanism of action the tools to assess the cellular effect the same way new pharmaceutical drugs are assessed and an advanced laser technology able to reach safely superficial and deep tissue at the correct dose then the potential is there for evidence-based medicine the first official medical guideline supporting photobiomodulation was published in 2013 by the myth the National Association of supportive care in cancer and the International Society of oral oncology for the Prevention of oral mucositis triggered by cancer therapy such as chemotherapy it was recommended with strong evidence and last months in july 2019 the recent update reinforced their position again and recommended laser therapy with the grade of strong scientific evidence it is not surprising to see the use of photo bomber nation more accepted among the medical practitioners for superficial application such as wounds diabetic ulcers burns and mucositis historically wounds and superficial tissues were the easiest tissues to find significant result because the factor of the depth of penetration does not interfere there still osteo arthritis musculoskeletal and neuro injuries in physiotherapy and rehabilitation have always been among the main applications of laser therapy in 2017 we can see the American College position granting a grade of strong recommendation in their official medical guidelines to treat chronic back pain all over the world for toba modulation is gaining more and more credibility among physiotherapists medical practitioners and specialists in pain management but also in hospital and universities doctors are promoting the use of photobiomodulation as part of their gold standards for treatment here are a few examples dr.

 Joe elfish from Toronto hospital in Canada discusses laser therapy in the treatment of burns or dr.

 Hugh Jones in the UK he is a Rheumatologist offering care laser treatment in private hospital or even public hospital like ease and cinemas NHS hospital in London NHS is the equivalent to Medicare in the UK they offer calendar therapy as well now let's look at the mechanism of photobiomodulation what we know and its limits red and near-infrared photons are absorbed in the body by chroma force there are many of them for example surgical laser targets water as the chromophore to heat water to a point of vaporization and destroy the tissue or cosmetic laser targeting melanin pigments on the skin to destroy cells with excessive melanin therapeutic lasers target mainly the cytochrome C oxidase so we will focus on it for a while cytochrome C oxidase is an enzyme in mitochondria that triggers many cellular and biological effects on photobiomodulation vasodilation analgesic effect and inflammatory effect increase cellular metabolisms through ATP production cell proliferation and tissue regeneration so what are the vascular effect triggered by photobiomodulation and how does it work for Toba modulation increases and your Genesis past and blood vessel maturation and trigger vasodilation please be aware that each time if you are looking for reference articles and publications it will be visible on the top right corner of the screen now looking at this drawing and image we can see that laser therapy through the cytochrome C oxidase triggers the increase of nitrous oxide ATP and carbon dioxide all three molecules are known for their pathway leading to local resolution local vacillation means better blood supply better tissue oxygen a excision to improve tissue repair but also a better drainage better drainage of a day my condition for surgery or after acute injury drainage of waste product such as lactic acid the key element for athletes to recover faster post exercise when practicing high-performance sports drainage of pro-inflammatory cytokine and other inflammatory mediators this is one of the main processes where photobiomodulation decreases inflammation this is an example that explains how vasodilation is assessed on a human being it is called venous occlusion plethysmography it is a gold standard methodology to assess the efficacy of new vasoactive drugs and omens before they hit the market as you can see in this publication see the top right corner this method is also used to assess the vasodilation effect or photobiomodulation this specific study with the khalasar compared three different dosage to find optimal settings power influence that triggers the best vasodilation effect for specific condition in this in the bicep the acceleration of wound healing and all the tissue involved the local Vizag elation and better tissue oxygenation but also cell proliferation with the increase in production of many growth factors this publication is one of the many examples that demonstrates an early wound closure with laser therapy many other publication described in details how photobiomodulation reduces the healing time with a series of cellular activity such as increase of macrophage and leukocytes activity increase fibroblast proliferation increase of collagen and increase in tensile strength many people wonder how it is possible to measure such small cellular activities well here is a technology called near-infrared spread spectroscopy analysis it can detect very small normal or abnormal cellular components and other small scale cellular function on a living organism as an example this technology is used for new devices such as a scanner of skin molds which give a percentage for the molt of PE cancers the same technology has been recently used for food analysis to detect their normal and abnormal composition the freshness of the product the presence of additives and other chemicals so when exploring the mechanism of photo by methylation it then becomes possible to measure very small components ATP level for example or the cytochrome C oxidase level of activity now quickly let's talk about the mechanism of action for the reduction of inflammation and the energetic effect triggered by ppm there are many good publication available that detail their pathway if you look at the top right corner you will find some reference on this slide in the next one there is room well both effects this slide resume most of the pathway resulting in reducing information the stimulation of vasodilation and an increase of angiogenesis that we talked about earlier and washed away Pro inflammatory mediators the increase of several molecules that are involved in inflammation and the suppression of inflammation such as leukocyte prostaglandin leukocytes the decrease of all the molecules that are pro inflammation such are the reactive proteins new clearing levels and interleukin-1 beta you can read the others as well the stabilization of cellular membrane enhancements of ATP production and many others similarly this side sum up the PBM pathway resulting in analgesia we can group the ones that influence neuroreceptor such as the increase of acetylcholine serotonin release increase of beta endorphins decrease of bradykinin levels and the one that influenced nerve cells itself increase their action potentials nerve cell regeneration ion channel normalization and blocking the depolarization of c fiber afferent nerve to assess the analgesic effect I would like to give you another example the earth domain it was studied in the late 90s to understand the energetic pathway of the paracetamol it is now used as a marker to evaluate the analgesic effect of new drug before they become available on the market PBM is able to activate the earth domain as well it means that photobomb iteration is able to produce an analgesic effect the same way as Pharma so pharmacological treatments for the curious I have listed a few recent applications about other mechanism not yet understood and opening new grounds like promoting cell survival modulating the immune system or transcranial applications for anxiety and depression many people ask do you have scientific proof that laser therapy works the answer is yes there are no doubts that photobiomodulation works the challenge now is to establish which settings are optimal which wavelengths are power how many joules which delivery mode continuous wave dosing superbowls which frequency of dosing what type of light source the difficulty is that optimal settings should be investigated at different depths and for each type of tissue chronic acute neuron control plus fiber glass etc for now there is no official consensus about which wavelengths power modality produce the best result only trends it means that the ideal laser technology will not only display one but all of these options this way the practitioner is able to adapt the settings as the latest research brings updates let's look at each of them and their influence on dosage and clinical results their wavelengths profuse generations later used to emit only one wavelengths and you would have to change the tip of the probe to change wavelengths now most professional laser will emit at least two or more at the same times from the same handpiece how is it progress is it better to emit one or four wavelengths in alternative well wavelengths influence the depth of penetration they have different affinities for different chromophores and the timing to obtain a cellular response also varies according to different wavelengths this graph represents the coefficient of absorption of each chromophore depending on the wavelength mo globin and melanin are highly absorbed in short wavelength but much less with longer wavelengths it is the opposite for the water chroma for the water chromophore is the main component in the body and when it is absorbed by water then the photon have a more difficulty to reach the other chromophores in between is the therapeutic window therapeutic wave lines varies from 600 nanometers in red light to 1100 nanometers approximatively in the in near-infrared so let's look at the coefficient of absorption of the cytochrome C oxidase the black line on the graph the maximum absorption is mainly in the eight hundreds nanometers but almost no in the 700 and it drops rapidly after 900 nanometers as well you can notice as well another peak of absorption in the 600 nanometers so this curve explains how for years before the mechanism was understood lasers has traditionally always been using wavelengths in the red light in 600 nanometers and in between 800 and a thousand nanometers by experience wavelengths in the 700 did not seems to perform well and now we understand why the red light in the 600 is almost always present in a laser device as it is the color of the red beam without it the practitioner could not visually see the pin the melanin pigments with the wavelengths of the red light 660 600 nanometers many photons will get absorbed in the surface which is great when a tissue targeted a skin a mathema and wound because would keep the focus on superficial lesions however melanin becomes an obstacle when the tissue targets it is deeper such as muscle and joints the question rises about wavelengths above the 950 nanometers what chromophore is activated as the coefficient of absorption or the cytochrome C is quite low the main theory is that these wavelengths are absorbed by water but not massively because the coefficient of absorption is still quite low just rising it would create a local gradient of temperature which would trigger a local vegetation and increase blood flow in the tissue also remember there are erythrocytes they do not contain any mitochondria so there's no cytochrome C present in those cells on these cells one of the chromophore is a mcglue P pigment it seems to trigger an increase in gas exchange and increase tissue oxygenation that way more chromophore may be found in the future with different mechanism of action so it seems logical to think that emitting several wavelengths at the same times would bring complementary effect wavelength also influences depth of penetration longer wavelengths penetrate deeper so among the wavelengths that targets the cytochrome C the 800 nanometers penetrate deeper than the 600 nanometers the 970 nanometers and above would penetrate deeper and target water chromophore mainly so again it seems logical to think that emitting several wavelengths at the same times would bring a complementary effect at various steps of tissue in this graph they measure the activity level of the cytochrome C oxidase a long time after exposure at various wavelengths this is just an example to show that each wavelength has a different timing in this example the 640 nanometers red light rise the activity level at 2 hours then drop to increase again at 24 hours post exposure the 830 nanometers follow the similar pattern with the first peak at 10 minutes then at 24 hours first exposure and the 905 increases at 2 hours so again it seems logical to think that emitting several wavelengths at the same times would bring complementary effects now the power previous-generation laser used only less than 500 milliwatts which is by definition the classification of 3 B lasers now most professional lasers will have a power that runs from low to high intensity power the average power above 0.

5 watts is by definition a class 4 laser it means that 1 watt power 20 watt power both are classified as a class 4 laser even though one is 20 times more powerful than the other so power depends on the light source it influences dosage at different depths in watt per square centimeter is in zone 2 square centimeters higher power means faster speed of treatments which allows you to treat larger area so do you get better result when you treat larger area the importance of the light source a quick reminder on laser physics laser lights are coherent and collimated it means photons emitted are going straight and in the same direction from inside the device it delivers an emergence beam and almost 100% of photon which the surface it allows the partitioner to treat in contact with the skin or from a distance without losing accuracy in the dosage for example wounds and Gurney's are painful and contact should be avoided similarly treating intro all intraoral e in dentistry or treating non-cooperative wildlife animals also requires the possibility to treat from a distance LED lights are not coherent and not collimating photon emitted are going in all direction it means that only a small proportion of the emission which the surface if not every photons reach the surface then it's less accurate for dosage and 10200 those particularly after a few minima ters distance when there is an even higher loss of photon that do not reach a surface in addition they are very small a few millimetres diameters they are grouped in cluster to compensate the beam is not a modulus so what do you think has a potential to bring the best clinical results omo genius laser light or non-homogeneous cluster of diodes or LED this is for surface water glass deeper structures what proportions of photons reaches them the proportion of photons which means deeper structures varies a lot from one individual to another from one type of tissue to another and depending on the wavelengths to keep in mind that many interactions occur as soon as the photons are in contact with the surface and only a small proportion which is a few centimeter if only 0.

1 to 10% reached the target then it means that with a 0.

5 of what Laser 3b laser on the 5 to 15 minutes will reach the target and just 0.

1 to 1 watt with a 10 watt power device typical high-intensity laser so when calculating the dosage in Joule per square centimeter it should take into account the depths of the target for example we could imagine wounds would require 2 Joule per square centimeters as 100% of the emission reached the surface whereas wood joints would require higher emissions like 4 or tendril per square centimeters just because a much smaller proportion would reach the targets as an example let's treat an elbow joint with osteoarthritis in the treatment area we include the joint all around the orbit and because a painful joint also involve compensation mechanism with the surrounding structures we also include in the treatment area the ligament intended insertion around the joints let's say 250 square centimeter the dosage is 6 true per square centimeters which is equal to a thousand Joe if we compare the low average and high average power device we can see a big difference in treatment time at 0.

5 watt it would take more than 30 minutes but just 2 minutes for 8 watt power the laser with a high intensity laser you were able to treat the larger area faster and less likely to under those with Lowell power laser in order to avoid long treatment time the doze is then calculated on a small portion of the injury less square centimeters area to treat means less quantity of jewel to deliver and shorter treatment time the probe is placed on a fixed point until it finishes to deliver deters then if necessary it can be repeated several times to cover a larger area high average power lasers that deliver photons much faster it means the dose is calculated to include the injured site and the surrounding tissue more square centimeters are covered in a scanning motion not on a fixed point so what do you think has the potential to bring the best clinical result treating a small portion of the injured site or the wall site and surrounding tissue you can see on the top right corner some of the mini publication comparing low and high power clinical results power density is if necessary some practitioners says that it is only a matter of time the result would be the same with the low power device as long as you stay long enough to reach the same amount of joules it is true for the number of Joule but not for the power density low power device remains limited in power density for deep tissues at the health practitioner you are likely to be familiar with x-ray technology if the x-ray machine is not powerful enough the radiography is not a good quality you can compensate to a certain extent by increasing time m eighth then the picture will be too blurry you need power to run good quality x-ray or even simpler let's look at an oven will you have the same result cooking your chicken at 200 degrees for 30 minutes or 100 degree for two hours it is the same logic with laser technology what per square centimeters power density does matter particularly for deeper structure now what about safety from a power such as 6 watts and above high average power generates some heat this level of power is used to target deep structure and a large area which means the laser is in constant motion to cover all the area like a scanner so the patient only feels the nice warm feeling heat is not part of the photobiomodulation effect it is a side effect a good one when treating joint in muscle anyway as heating the tissue helps with muscle relaxation and stretching it is not recommended recommended for wounds and in burns for example but again for such application the software would use a low power density because the tissue targeted is so superficial and at low power density there is no heat so it is safe used outside the way it should be high power laser could be dangerous the same way a kitchen knife or hot water bottle is dangerous it can damage the eyes and this is a reason why some states require a class 4 laser license and helps professional are eligible for it home user are not allowed to possess or use one it is for health professional only risk a laser when you receive your device we always include safety technical and clinical training this heat is one of the limits of continuous-wave lasers there is one this is one of the reason pulsing and super-close laser have been developed and we will explain this modality in a minute again I have included a couple of references that show the safety of a high-power laser there is one from the public london hospital cinemas they released an indication pan flag for patient and it's precise well Callister therapy do not burn the second is a study over 120 horses done by two european university together horses are much louder than human being and they use quite a high power density for treatments among the conclusion they stated that high-power laser can be safely used so now you can answer yourself the question what do you think would give the best result when treating dipped structures low level or high power lasers the last parameter to understand is the delivery mode at first there are particular sirs used to emit photons only in continuous wave today professional laser can emit in continuous wave pulsing and superpose it is difficult to say which one is best for which condition or type of tissue however each modality has advantages and drawbacks so it would make sense to have a laser design to give access to all the modalities and use the advantages of each mode continuous wave means that the power of the laser is on all the time of the treatment the peak power is the same as the average power in contrast those things means that the laser alternate time on and time off for example 50% on and 50% off this pulsing can be very fast or very slow the speed of the pulsing is defined by a pulsing frequency which varies from 1 to 20 Southerners the original is 1/2 the peak power because in this case the laser is 50% of the time off finally the super poles it is a form of pulsing but with a very high power so the device appears very powerful but the time on is very short just a nanosecond tee-off is almost hundred percent and the time on is really tiny so in fact the average power the true power capacity of the device is really low knowing that for each of these modalities the power density of death will be different to use the in click all result are the same when the same dose is delivered in continuous while imposing unsuitables clinically what does it means continuous waste laser because the laser is on all the time this modality delivers a large number of rule faster than any others the treatment time is shorter for superficial application low power is required so there is no specific issue however for deep tissue application high power density and what per square centimeters is required and continuous-wave laser are limited to the do to the the heat developed at the skin level this is why pulsing and super pulse laser technology were developed tossing lasers it increases the treatment time because 50% of the time the laser is off but it is safer for darker skin where melanin tend to retain more photons in the surface the other advantage is that pulsing laser allow the practitioner to choose one frequency from one to twenty seven Hertz according to the type of tissue targeted we'll talk about it in the next slide super pulsed lasers it was the next step in laser technology it allows high power density in deep structure in watt per square centimeters the high power density that otherwise would cut and burn the skin but because it is pulse on such a short period of time in nanoseconds the tissue in the surface do not have time to burn and it is very safe now class 4 and class 3b can both be a super pulsed laser we cannot say that super pulse penetrates deeper than class 4 or class 3b the drawback of this super pulse is that because a super pulsed laser is on for such a tiny period of time in nanoseconds its capacity to deliver quantity of jaw is really low and the treatment times is really long so we are back to the same limit as low-power laser to 3 B the dosage is calculated for a small portion on a fixed point and to have a more convenient treatment time the good news is that Kay laser has developed the ISP intense stripper poles we take advantage of the safety and high power density in deep tissue of the super tools and of the capacity to deliver a large quantity of jewel-like the continuous wave now just a quick word about tossing frequencies do you think click or resort are the same when the same dose is delivered at one earths person or the southern edge pulsing of 20,000 earth pulsing well as if it was not complex enough publication now reveal that each tissue tends to respond better to some specific frequency and a bit lest from others so there is no perfect modality each of them has benefits and limits what about having a laser able to use all of them to use all the advantages this has been developed by Kerr laser as the multi phase most lasers are mono phase it delivers photons the same way during the laser session the practitioner can choose a specific settings at the beginning the posting frequency or constant continuous way and the whole treatment will be delivered the same way the multi phase means that the treatment session combines several phases with various delivery mode see the example in this table twelve phases phase one is continuous wave phase two is pulsing at hundred Hertz then phase three is posting with another specific frequency and so on twelve phases with different modality and each phase has a specific power time and delivery mode this way all the advantage are covered it is safer for deeper structure in dark skin high power density even in deeper structures high average power to deliver a large quantity of jewell and cover large area with short treatment time it used many different pulsing frequency to target as many different type of tissue as possible as you can see calculating a dosage with the multiphase can become quite complex luckily the software has many presets program to calculate the correct dose for many common application from acupuncture points to neck pain diabetic ulcers osteoarthritis for surgical procedures and many others ideally in the future we could imagine a technology which could read the cellular content and the coefficient of absorption specific for each person then an artificial intelligence who would deliver the exact dose required for this injury on this patient laser technology is complex so well done to everyone who listened to the end and thank you please leave your questions and comments below and I will reply