Professional education
A must see talk on Endourological lasers in tissue applications
Dr. Fernando Gómez Sancha · ICUA
Dr. Fernando Gómez Sancha · YouTube
Language: English. YouTube audio metadata.
Professional education. May contain surgical footage.
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About this video
A lecture by Dr Eugenio Ventimiglia on laser physics and laser–tissue interaction for endourological tissue applications. The description introduces it as an explanation of the basic concepts relevant to clinical laser use. It does not list individual laser settings or a treatment protocol.
This is an excellent talk on laser-applied physics by an Associate Professor at the University of Uppsala in Sweden, Dr. Eugenio Ventimiglia. He is one of the brightest young minds in European Urology. He manages to explain the laser physics that matters for clinical use simply. I saw him delivering his talk at a recent meeting in Modena, and I was dying to invite him to publish it on my channel. You have to understand laser tissue interaction if you use lasers for tissue applications, and this is an excellent primer to understand the basic concepts you need!
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No clinical case details have been extracted for this video.
Original title and description on YouTubeSource checked: 2026-10-06.
Available transcript · English
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- good morning everybody and thanks to Professor gomet sancha for this very kind invitation to discuss Urological lasers and their application in prostate nucleation in the next minutes I'm going to give an overview how Urological laser work what is a laser of course how to use them and some Novelties regarding the topic starting from the definition a laser basically is light the reason why we don't see the light coming out of the laser fiber is that laser in Urological applications they emit in the infrared Spectrum meaning that it's not visible but still it is a light which is coherent Amplified and has an effect and most importantly it is a light that has a unique wavelength meaning that each
- laser is characterized by a specific wavelength and these will have specific effects which are peculiar to each Laser Source thinking of urological lasers we have to consider that they are mostly based on these two elements holmium and thulium and the lasers we know very well it's of course holmium yag but still thulium yag is also very utilized and the most recently introduced is Thum fiber laser we're going to see in a wide differences in terms of application for them few key Concepts which I think are really useful to understand in order to realize how these lasers work are basically that Urological lasers they are applied in a Aquos medium they work in the water and each specific laser is
- characterized by a specific and different absorption by water holum yag is absorbed quite decently by water but Thum yag and Thum fiber lasers they are absorbed at least two times to four times as much and thinking of laser emissions in terms of concept we see that the laser can emit either in a continuous emission which never stops this has a high thermal effect low Peak power and it's very utilized but only for tissues because the low power doesn't make these lasers appliable to lithy instead we if we have a pulsated emission the same energy can be emitted in discrete pulses there is a pose between in between different pulses which allows tissue to relax in terms of thermal dose and temperature uh they
- have a different effect we're going to see now why they can be used either for tissues and Stones another key concept which is very utilized by companies and needs to be understand by us as urologist is that different machines they have different total power values so low power lasers they are not Lous lasers they are very useful for treating Stones they are limited by maximum power which arrives up to 35 Watts they can be used for prostate nucleation but still if you want to have a proper nucleation medium to high power lasers are the most utilized and perhaps those who perform the best for this type of procedures and we Define a medium to high power lasers whenever laser has at least 60 up to 120 150
- watts let's get focused a little bit on laser functioning and specifically how laser work inside the machine so very few technical details which can be somehow annoying but at the same time I'm sure and confident they can help understanding how the laser work during the procedure very quickly holum yag laser it works whenever a flashh lamp activat a holmium yag road which emits its own energy and the CH specifically wavelength of emission which is the one of Alum yag which is Amplified and reflected within the machine and eventually emitted by the laser fiber we know that a low power laser is composed by Just One of These cavities and whenever we combine two or more of the cavities we have an higher and high
- power machine Thum y Glazer is very simple again very similar to holum yag instead of The Flash lamp we have laser diodes which allows this laser to perform a little bit differently but the key concept is very similar in terms of functioning and a little bit different different is the folium fiber laser that we see here we don't have a cavity which amplifies light but we have coil silica fiber which is doped with thum ions that's why it's called Thum fiber laser the light is emitted by laser diodes which gets Amplified within the fiber and eventually emitted by the operative laser fiber itself getting a little bit towards what's more interesting for us as urologist and though and and therefore
- getting more closer to the clinical application let's get to see what happens when the light emitted by the laser meets the tissue so we know that like we said before the lasers they work in a water environment which means that whenever the laser comes out of the laser fiber what happens is that the water under goes an EVAP vaporization process which causes this very B bubble to form to explose and to collapse so each of this laser is abor absorbed differently by water and therefore the effect that we have in terms of bubble will be again different another key concept we need to understand is that each laser can emit in pulses and each pulses can be different according to its characteristics so the same amount of
- energy that you see here it can be emitted in a very short time frame which allows the peak power to raise which means that all the energy is condensed in a very short short time and will be let's say more abrupt in terms of emission and arrival to the tissue at the same time the same amount of energy can be emitted on a longer time duration which will be delivered more gently to the tissue at the same time the peak power will be lower and this has very important effects in term uh and differences in term of the way that the light interacts with the tissue itself this is very very well explained by the two different effects a laser have in terms of emission and delivery to the tissue the first one is the
- photothermal effect which is the light hitting directly the tissue and determining an effect the second one is this the so-call photoacoustic effect the bubbles that you've seen before that forms at the tip of the laser fiber it explodes and that energy formed by the explosion and collapse of the bubble will determine a second effect on the tissue and we're going to see in a while why this can be important when treated prostate and during prostate nucleation now we have the laser fiber we have the energy coming out of the laser fiber and hitting the tissue at the end of the day after all these technical details what we want to know is the way that the light interacts with the tissue which means that we want to
- know if a laser is good in inzing the tissue at the same time time we need some coagulation and we want to know whether the laser is good or not at coagulating the tissue so we want some we want to estimate what is the incision depth for each specific laser and at the same time we want to know whether the coagulation era is good or not and keep in mind that high power laser which emit very big and explosive bubble they will be really good at in sizing the tissue but at the same time we will have due to the less gentle delivery of energy a less important Co regulative effect whenever you have a low Peak power it means that you will have a less disruptive bubble but at the same time you will have more eat diffusion and
- better calulation just to be clear this is a tissue treated with the laser you see that decisions depth is measurable very well from this point of view at the same time the coagulative area it informs it gives some information in terms of coagulation properties of the laser itself just to give some numbers you see here that the holum yag laser is able to in size up to 4 mm according to the specific parameters you're going to use and it has some decent coagulative profile but still we have differences in terms of laser like we've seen before they can be absorbed more or less by the water but at the same time the pulse that is generated by different lasers will determine different effects on the
- tissue you see here that we we have big a big very tall pulse a very tall pulse means that it has a very high peak power a short parse dation it means that the energy coming from this laser which isum yag with a short pulse will be delivered very abruptly to the tissue in a very explosive way as you can see here the bubble of volium is very big and very explosive at the same time volium yag can be stretch in term of PSE have a lower Peck power but if we are looking for very low Peck powers we need to move to folium yag and also to folium fiber laser you see here that the bubble coming from folium fiber laser it's it is much smaller in diameter and very less explosive than alium yag itself at the same time we know that the
- pulse coming from holum yag can be split can be stretched and when it's split this time you see a double pulse coming from the first pulse causing the first bubble and the second pulse going through the first bubble in a way that it allows the energy to be better delivered to the tissue and in a certain way the PE power is lower so you can imagine that with this laser pulse more energy will arrive to the tissue having a better thermal and coagulative effect so do we have some way to evaluate these differences in terms of laser properties of course we know that when we use them in the clinic that the effect will be different on the tissue but at the same same time we know that in the lab we can estimate all those
- parameters and you see here the difference so H mum yag you see a very deep incision but at the same time the tissue is very well dismembered by the bubble and the explosion of the bubble itself you see on the other end that the cut with thulium lasers it is less profound less deep at the same time it is a more precise incision because the bubble doesn't explode the same way that it does with holmium but an important difference is that the coagulation with thum yag laser is very very high and much higher than holum yag and you can estimate these numbers and you're going to see that incision depth is higher with alium but at the same time the de coagulative area is twice as much with folium and just to have a little bit a
- little a quick recap of these two lasers in terms of property you're going to see here that holum yag it has a very high Peck power compared to thulium yag and also thulium fiber laser it is a pulse laser Thum yag can work and Thum fiber laser they can work in both continuous and pulsated wayag is a more explosive deliver of energy which means an explosive bubble which means deeper incision a dismember tissue but at the same time less coagulation as compared to folium yag and folium fiber laser so we've seen before the laser PS can be stretch and we can have short PS and long pulse for holmium at the same time the pulse can be modulated pulse modulation was mainly created for stone procedures but at the
- same time it turned out to be very useful also for tissue procedures you see that when you have a short pulse with alum the bubble is very explosive when you have a long pulse the bubble is longer and a little bit less explosive we also know that the laser PS can be split which means like we've seen before that the Pak power will be lower and the and the delivery of the energy will be a little bit longer and more gentle as compared to whole mum yag and leave with this as a quick recap of the laser characteristics uh it's a lot of numbers and you find here the publication if you want to look at them uh a little bit more relaxed but still different wavelength different absorptions by the water lasers can work
- imp pulsated way some of them only pulsated some of them can work also as continuous laser we have different ranges of pulse of energies but what I want you to focus on is that different lasers they have different Peak power values we've seen before again and I want to stress this concept that higher Peak power will imply more explosive delivery of energy to the tissue less culation and more uh better decision depth and better section of the tissue and you know if you like olp very much and if you follow this channel I'm pretty sure that you do you see that in order to have this very dective effect of the prostate from the considering the denoma from the capsule you will need this type of thissection
- that you're going to have very well with olium and a little bit little bit less with other lasers another thing is that olium is a very modulable laser and of all the lasers that you have on the market now is the one that allows you to perform your procedure with a very very very wide range of pick power values and we're going to see that a new innovation coming to the market will allow to lower the lowest range of peak power for holmium up until 500 matching closely Thum fiber laser So eventually a quick recap of these three different technology if you want to think of them in terms of tissue appc ation is that holum yag works very well with a photoacoustic mechanisms which implies a wider incision depth and
- dissection horum can be pulse modulated meaning that it will have an enhanced photothermal effect and again a better coagulation we have Thum yag which can work in a continuous way it will be mostly for thermal so a wonderful coagulative effect but still some carbonization and in terms of dissection it will not be its best characteristics Thum fiber laser it works imp pulsated way it does have a photothermal effect with a minimal photo acoustic which is due to smaller cavitation bubbles coming from this laser and eventually Thum yag it also works in a pated way meaning that it could be a compromised or let's say uh it meets halfway the characteristics of holmium yag and folium fiber laser and
- with this final recap I really want to thank again Professor git sancha for this opportunity and you all for your attention thank you very much