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So this was test on monkeys rest on day in 1914, um, issue with, um, growing life. Um, it wasn't broadcasting from your side on. I've been slides, but is it okay if you just go back again? I'm sorry. Yeah, with the broadcasting. Sorry, guys. Again. Um, I think I should be able Teo stop now. She just thought that, um But it was a just a mission with broadcasting little thing. Everyone's whatever was listening. So you stopped again. I'm sorry. That's fine. All right. I think everyone should be seeing it now, so Okay, there we go. This thing. Oh, sorry about that. So, um, I will be discussing, um, stereotactic radiosurgery in neurosurgery. So, um, this is one of, um, numerous numerous developments in your surgery on, but, um, hopefully, um, yeah. Oh, I'll go through 30. I was interested in this topic when I was doing some research. A systematic review on D. Looking at recent your surgical developments, sir. Tactics. Really. Surgeon has been around for quite a while now, but it's Muir developments isn't your applications are still being explored, so I intend on for pissing on that. Um, yeah. So what is your tactic, radiosurgery. So, um, we have severe Texas, which is, um, which can be broken down into steroids on Texas cirrhosis. Meaning something that is three D on Texas implying an order. The arrangement on this is usually a cciw by CT, MRI, or other imaging techniques on it can be used to diagnose. So, for example, looking at tumor size location, any metastases, uh, as a treatment measure. So, um, looking at so exploring whether we can lesions certain areas, um, on do that, that kind of would be useful in things like trigeminal neuralgia in which they usually intend on lesioning part of the lesion or damaging part of the thalamus. For example, eso resections of just removing the tumor, for example, on, um, video Marcus. So these are reference points that we use in order to, um, gauge whether where we should put the electrodes where where should be target them to ensure the most accuracy is achieved? No, um, redo surgery. So really, a surgery involves photons. Gamma X rays on it involves protons, um, on there, usually targeted at a particular region on, But, um, and just to create the distinction between radio surgery and radiotherapy. Um, the intensity undulation off. Um uh, reading a surgery is different compared to radiotherapy on. That is because, um, video surgery delivers a higher dose of radiation to a much, um, smaller point, whereas radiotherapy usually involves, for example, whole brain radiation. So it's it's not a selective as this on. It's likely to damage more tissues. Um, yeah. Just to put that all together, a stereotactic radiosurgery is a very precise form off. They repeated radiation that can be used to treat abnormalities in the brain and spine, including cancer, epilepsy, trigeminal neuralgia and Avia on. I just wanted to point out that there are applications outside of neurosurgery. First, you're attracted radio surgery as well. Onda. Um, I will be referring to this as SARS throughout the presentation. So, um, the history of near surgical steel, your taxes, so it looks okay. Um, it be done in 19 oh eight records. The in clock on they developed a basically a map, a three D map off, um, to guide these electrodes and make sure that they're all pointing in the oh, same direction onda That will ensure that they can have a more precise target on day was done on the monkey brain with various skull and mark so usually fiducial markers on. But then, in 1914, the's interest The stereotactic instruments were patient ID on, then further developed for human use. Um, alongside Aubrey muscle in, um, in 1918 on. But they weren't help for human use, but they never ended up being used. So this technology was still very new at the time. Um, so there are a few issues because it was quite difficult to map the skull land marks on, but, um, in 1947 Spiegel decided to develop a stereo and separate, um, so that just means, um, a form of intracranial, um, surgery Onda. This is when it was first used in humans onda. And then this year, tactic frame was developed, which helped localized dream up green matches structures. So a stereotactic frame is a frame that goes around the head on allows. Um, it kind of allows the placement of electrodes to be right. So as I've been seeing a lot, it's really important to have the displacement. Well, um, on day before, it wasn't really It was kind of mobile. You could take off and then put it back on. But here in 1951 lexo developed a pin fixation so you can put pins and connected to this girl on. But that was, um that was on more accurate and a lot more beneficial. And then they developed certain, um, certain markers off where we should put these pins or where we should put the fiducial markers on. But they were done in the anterior posterior commissure is on down towards the later he it later part of the 20th century. Um, they went into, um so nerve brachy in Japan also developed a similar frame on Then, in the late 19 seventies, 19 eighties, CT and MRI was better developed, which meant that we could, um, which meant that we could use this again for redo redo surgery on. Currently, we're trying to improve the targets on broaden it uses. So it's not just used, um, for team raises. Now it can be used for a neuropathic pain unsold. So how does it work? Know we have multiple beams are high energy beams that will converge at certain points on Deacon Bridge. Ince's aided by various things such as a collimator. Um, but I'll go into that later on on. But, um, so, yeah, the three d computer as imaging is an important, um, an important development which helps us use it. Um, and again is you X rays, gamma rays and for protons are necessary for this on the same of the treatment is to cause radiation induced any damage. Know, um, by doing radiation in DC any damage? We're gonna, um, change the iron concentrations we intend on changing the, um, the iron concentration. Sorry, um, andi affecting the the amount of free radicals that there are on. But this would this would ultimately destroy the cells. Prevent, um um, from reproducing and so on on it also affect the vascular endothelial, which is really important for us. Um, a n'importe. No side effect to consider. Especially when we're looking at the brain. Because if you fact the vascular endothelial gonna affect the blood brain barrier. So I'm moving on to the technique, so usually you can use a special ed How specialized helmet. Or it could be from this. Um, if if you show your reference books So again, the markers. I was speaking about idea on Do usually would use MRI C two or angiogram, so a little continuation on from that. So usually the dose is the dose is is measured in Gray's. So that would be GI. Why Onda SRS gives the biological equivalent of 5 to 6 weeks of daily conventional radiation therapy. So there is a lot of radiation that's been given in a single treatment session for a SARS, a more manageable and perhaps better. In some ways, fractionated stereotactic radiotherapy is going to be used for It is a form of radiotherapy that allows us to use, um, less, less intense dosage. So, um, on go up at greater intervals, so that would allow for more tolerable, perhaps treatment. But then again, it does depend on the patient. So, uh, the benefits so is a non invasive procedure, which means you won't have the side effects of surgery especially, um, neurosurgery, which would include things like infection or blood loss on. But the fact that it does not harm surrounding tissues is also very beneficial, because that means it can, um, we have a greater accuracy for our the area that we're trying to focus on on. Um, it also has on also, um, with the whole brain. Radiotherapy, for example, which is mentioned here, is well, that is likely to damage of variety of structures in the brain. It's not just going to damage that tumor or that ABM it's going to damage the whole lot. So it's it's a lot better in that sense, and it also has a better side effect profile. So they're very similar. A shins off. Um, so tactic radiosurgery Ah, one of these in foods restricted treatment. So to be considered for tactic radiosurgery. It's very you have to meet certain criteria. One of the things you have to be is the tumor itself would have to be less than three centimeters. Um, Onda. There are other limitations that you have to have. So, for example, whole brain radiotherapy has to be treated. You already gone through and has been successful, so it's kind of used as know, really last resort. But after most of their options are, eggs are exhausted. No, his geological verification is absent. So what I mean by that is that if we were to do near a surgery on, we were to resect a tumor, we could send that tissue to a lab and confirm, Um, what type of tissue is whether it's metastases, where it's come from and so on, whereas with SRS, this is a very difficult thing to do because obviously we're not taking any tissue from anywhere. Um, we're simply lesioning it. So that level of both diagnosis and looking at the on treatment is not no longer present on does a lack of immediate effect. Because again, um, this will also tie in with the mass effect, which I will go into, Um, because if you just, um, if there's a reasonable sized tumor on, then you give it radiation. It's likely that seeing the effects would be quite delayed because the tumor is still technically there. It's just a matter of it not growing or not developing further on mass effect. So, um, this is in, um, three phrases. It just means that any effects that are not directly related to the tumor but have some sort of secondary effect on the body. So, for example, if you have a tumor of any size of the brain, that's gonna affect the intracranial pressure. If if it's the intracranial pressure that will present with symptoms, headaches, um, and so one. So this mass effect cannot be eliminated by SARS. So it's something to consider, perhaps alongside other treatments. Oh, yeah. So some of the complications are that we have. So they're cute, which for? Within six weeks. So headache, nausea, fatigue. And these are usually a consequence of cerebral edema on, as I mentioned before, SARS is going to affect the blood brain by you. And by affecting the blood brain barrier, you're introducing the chance of having an edema, more foods leaking through the capillaries, so that will lead to increased. Um, I see p on these. So sub acute. So which would be solemn? Nessen. So this is just a fancy bracing drowsiness, um, on fatigue. So, um, this is usually a consequence of diffuse demyelination, whereas the late effects after six months, I usually, um, a side effect off white matter tract damage following an injury to vascular endothelial cells, um, or alternatively, accidental demyelination or coagulation across this and so on. And that means that because there's so much damage on a cellular level, it's usually permanent on, But, um, this will lead to progressive memory loss, radiation necrosis. Um, wasting of neurological defects is well, no indications. So, um then I've mentioned this before. Reiterate smaller masses with a maximum three centimeter diameter brain and spine metastasis. Use any primary tumors. Arterial venous malformations. Patients are resistant to hold brain radiotherapy, onda trigeminal neuralgia. Um so including any conditions such as chronic neuropathic pain as well. So it's not just limited to tumors. Now, there are three types of SARS, which I will discuss. So the first one is the gamma knife developed in 1967. There are about 200 or to roughly 200 sources of radiation arranged in a comical tungsten arrangement. On this cobalt 60 radioisotope will undergo radioactive decay on, but, um, it will produce beater particles on day to day. Um, a radiations of these energies. So just for just for a quick definition, M e v just means mega electron votes on one leg. Electron vote is the energy gain by an electron that accelerates through a potential difference of one fault. Um, so the effect of energy of the focus beams will be 1.25 mega electron volts. No, um, this vehicle rain, there will be a spherical array, So kind of you can see that older. These gamma rays are kind of a sphere on the patient, um, via collimator helmet. So ah, collimator. Which I mentioned before It just allows these, um, these beams to converge on by convergence. That means that they will be able to reach their target with greater precision, which is what we want. This is currently in. It's fifth generation on day one of the drawbacks of co Bob Sorry of gamma knife is the Colbert source must be replaced. It has a half life of, I think, 5.26 years. So, um, if it will need replacing eventually. No, Um, this is a linear accelerator system on do it involves. It was developed in the early 19 eighties on it uses high energy X ray. So the previous one used tamary is this one is, um, utilizing any high energy X rays on the he component. For this is a magnet run. A swell, which, um, is a source on is a source, and it kind of amplifies the micro waves are there? Um, andi, That allows, um, the movement for that loss for us to control the movement of the moving high speed electrons. Um, Andi also expired. Thermodynamic admission. So thorough neck just means that there is a filament of some sorts of a metal filament and then that is heated on upon heating. It's gonna release electrons. No, um, the voltage usually used. Sorry. The energy of the electrons is usually six, uh, mega trump boats for SARS. And again like I mentioned before, we also do the calling me to hear now when we use protons, it's slightly different because you have a sink drawn or sexual turn based device. Now, this is just a fancy way of of describing the A device that will involve the ionization of hydrogen on that is going to be how it will release it's protons. Um, Andi. There's also cool on collisions that occur here. So that's just another way of saying that there will be a nucleus that will Oh, it's basically charged particles interacting with each other on gliding, but it's usually a nucleus and an electron, and hence the protons, Um, and this uses 20 to 190 medullectomy roads of energy. On this will also involve thumb the movement of protons. Um uh, in a kind of in in a very particular way. So proton beam themselves will penetrate tissue, and when they penetrate tissue, they'll lose energy on this energy loss is inversely proportional to the square of velocity. This means that on a dose distribution curve, you would see a gradually rising, um, gradually rising dose. And then there would be a shop increase in the, um in the dosage on. Then that sharp increase is what we call Brian Peek. Um on This is a much rarer option that isn't used as much compared to the other two. So the future off SRS so f s are. So I mentioned this before. This is just fractionated. So your tactic radio surgery. No radiotherapy on do this. Basically, this method basically allows for a lower total treatment dose if we use the example of, um optic apparatus maximum dose associated with technically reasonable risk of rating, um, risk of radiation induced necrosis for the optic nerve. So this is just saying that certain areas of the brain, uh, very sensitive the optic nerve is one of them on, but it's capable of receiving 10 graze in one Fraction 20 graze in three fractions and 25 5 fractions. So this allows the targeting. I've been getting more high risk structures. Um, on there's lower radiation necrosis on radiation induced optic nerve neuropathy. So just optic nerve damage is a lot lower on. You're less likely to have tissue. Death on this can create large lesions. Onda, um, again, it can work in lesions close to high risk structures. And this is just the limited. The dose limitations for SARS, which are 25 graze religion. Listen to centimeters. 18 great solutions of 2 to 3 centimeters on 15 for tumors, which are 3 to 4. So as, uh um, as the radiation increases, the size of the tumor should be less to pre to have the most optimal results. So why don't we just use efforts are if it's seemingly better and it has selenium benefits. So four brain metastases in particular, there are a number of things that we have to consider. So, um, few of the things, um, which we have to consider is the physical properties s o the tumor size. It's margins. Um, the optimal doors. Onda biological factors include the histology of the metastases on so on. So clinical factors also include life expectancy, home or bities access to the treatment. Um, but there are also clinical trials that are looking into its efficacy. So we're likely to see more of this, um, in the upcoming future. So I thought I would just I won't be able to see the answer may be to the end, but I thought I might just add this quiz question. Um, yep. I'll let people and send the chart. And I'm like, you know the answer, because I'm not sure you can see it, So yeah. So just the center in the chart. Mm. Yeah, I'll leave another. There is seconds, maybe. And then I'll move on to the answer. You couldn't put whichever, and so you guys are thinking about that. I'm not less is a role. Yep. Yeah. Would you may be able to, um, read them out loud? Just the options. Okay. So ah, patient has a small cell. Sorry. Patient has small cell lung with a carcinoma with brain and spine metastases. He presents with blindness, which has progressively gotten worse. CT reveals a large mass within the brain with the diamond or five centimeters. That's option A patient being present with hearing loss tonight. This vertigo on did. The MRI reveals a brain mass with the diameter of two centimeters. Patient C has been newly diagnosed with a brain tumor on has recently started whole brain radiotherapy on highly patient D experiences. Headache, gait, disturbances, mental changes on dizziness. CT reveals a mouse with the diameter off three centimeters. Okay, so far, I have 1234 B's and one C. Um, I will just move on then, um, on the onset is indeed be, eh? So I'll just go through where the other ones would be wrong. So patient A has worsening blindness. So this is, um, suggestive of an optic chiasm use in on, but so a potential compression as a result of the tumor and so on. So that would be quite dangerous as we mentioned that a sensitive structure on the tumor size is also too big. Patient be presents with hearing loss, united vertical. So that's kind of, um, leading to a acoustic neuroma of a similar sure normal, which was one of the indications off a off SARS on. But, um, it also meets the size report. The diamond to requirement on patient C has recently started whole brain There be. So this was kind of, um it was kind of a bit of a trick question because, um, when we don't have enough information about the tumor size on another reason, why is because we don't know how the what the outcome was after whole brain radiotherapy, because, if they have recently started, were unlikely to know whether it's, um, whether it's suitable for the patient. So um yeah, that's why she was a bit wrong. Andi d um, it's indicating a cerebellar mass on. But, um, the cerebellum is also another relatively sensitive area for Essar's on we. As far as we know, we don't do it there. So I was as well as that. The diameter was three centimeters, which was kind of borderline. Um, so I briefly went through What is SARS? The history, benefits and imitations? How it works. Complications and indications types on D f s are. So thank you for listening. Amazing. Thank you so much. Honey. Eso I will leave that shot open for any questions. Now I'll give you until 22 7 so about 34 minutes for any questions, just writing down the truck. If anything shows up, I'll let you know. And I'll you can. Now, um, if you just stop sharing, it's great and you want to just come back to the shot and you can have a look at the questions. Um, and yes, they have any questions. Please leave them now. What I'll do now is I'll share the feedback form with you all. It'll be sure to be email, but it should also come up automatically at the end of the event on most everyone. Not so, uh, be in the meantime, If there are any questions, please leave the hand the chopped if no oh, close your about it in a few minutes. Thank you so much again, honey. It was a very good lecture, and I'm sure everyone liked it is. Well, there's a lot of diffuse back eso. There's a question. You said this technique is used for relatively small tumors. What do you see? Any future for this to be used in conjunction with regular neurosurgery for larger tumors? I would definitely, um I would definitely see this, that going forward, it would be good to use along side, greater team. So if there was a large tumor and they didn't your surgeon that tumor to resect it, um, I think that the remaining they would be able to resect less of the tumor on deal with the rest using SRS. And I think that would be a much more beneficial way of dealing with any sort of bring teamwork. So, yeah, I would definitely say, but that would be a good future application. Um, I think I think it's being recorded. Yes. Old events are reported nil, and they go straight. Teo are metal age, so they can be reviewed after my anyone hasn't come to you. But so you can come. You can see the lecture itself, the reporting after the event of stopped. Yeah, um, in any other questions? A I applications. That is an interesting question. I don't think I have considered that, um the, uh aspect, But perhaps, But would take What do you mean by a appreciations in terms of, like, training surgeons how to use it, Or I don't know too much about, uh I see. Okay, Yeah, because this procedure within itself can Could potentially be automated. A lot of neurosurgery is going towards that direction, Um, on. But I think that yeah, definitely. Because again, at the end of the day, um, we only need someone to kind of tell these really big machines. Like we saw the gamma knife on. We saw the the little accident. We just need something to tell Teo. Precisely. Focus it. And then from then on, you can kind of get a night idea of where the tumors usually are, how we can deal with them on so on. I I do think that it won't be completely automated in terms of, um um a I wishing many I don't I think they're still will be a need for in your ascension under expertise for this procedure. I don't think that it could be completely, Um, at least for now. At least for now. I don't think it would be, um, feasible. Yeah. Yeah, I haven't I haven't read too much about near a navigation myself. Um, but he had this really interesting. Okay, Yeah. Um, thank you for listening. Thank you guys. Okay. Okay. And if there are no other questions, um, if you want to leave any and protect details for everyone. You know, I I will finish this session sent, and I hope everyone enjoyed it. This is our last SLT for this. You ever been to He keep an eye on our social media for the next ones or even in our metal pitch goes away. The events are shared on our male page. Have a lovely day and I'll see you soon.