Hello everyone, thank you for joining today's Best of Qads webinar. Latest developments and novel clinical Uses for SGRT by Michael Talhammer, Chief of Radiation Physics at Advent Health in the Rocky Mountain region during QADS 14 earlier this year in Portugal. This presentation was delivered as part of the QA Endosymmetry or Treatment modalities panel, and in today's webinar, Michael will discuss his clinic's experience with SGRT and highlight the latest clinical uses. Before we begin, we do have a couple of housekeeping items that we want to cover. First and foremost, if you do have any questions during this presentation, please enter those in the left of the presentation screen and we'll address the questions at the conclusion of today's presentation. In addition, a recording this presentation will be sent out after the broadcast to all of our attendees and will be available for viewing on the Sun Nuclear website. So with that, I'd like to introduce Michael in his. Today's presentation again is the latest development of novel clinical uses for SGRT. Michael is a chief Radiation Physics for Advent Health based out of Denver, Co. His primary research interests focus on applications of SGRT to high precision treatments and understanding the various sources of uncertainty and stereotactic radiosurgery. He served as a guest lecturer for several academic institutions on a variety of topics including SGRT, stereotactic radiosurgery, and the use of statistical process control, or SPC, to improve radiation oncology quality management programs. He's a past president of the Rocky Mountain Chapter of the APM and served as a clinical consultant for TG3O2. He did his postgraduate training at the Clinic Cleveland Clinic where he specialized in therapeutic radiologic physics. He's been characterizing the capabilities SGRT systems and comparing them to other high precision delivery platforms such as Zapex, Cyberknife, Brainlab, Game, Gamma Knife, Variant Edge and other frame based stereotactic delivery systems for just over 15 years. In addition to his clinical practice, he serves as CEO and Chief Science Officer for Parkolit Consulting, helping industry leaders develop a variety of products spanning the field of medical physics, telecommunications, and satellite imaging. Before we begin today, we do have a poll question. We want to learn a little bit more about the audience and who's attending today. It's a pretty easy one, but are you currently using or do you have plans to add surface guided radiotherapy to your clinical environment? So if you could go ahead and answer the poll just by clicking on the choice of the two options there, yes or no, We'll go ahead and give it a minute so everyone has a chance to respond. And then we'll get into the meet of today's presentation. Give it another 10 seconds or so just to get a better feel for those aren't joining us online today. We'll go ahead and we'll take a look at the poll results. It looks like we've got a fairly experienced audience here, Mike, with respects to sites that are either using SGRT or planning to begin in the near future. So with that, I'll go ahead and and turn the the presentation over to you for again, the best of QADS presentation floor is yours. All right. Thank you. Thank you for that introduction. It looks like everybody already knows everything I'm going to talk about today based on that poll, so as be a quick talk, but my name is Mike Tallhammer. I am the Chief Physicist for Advent Health Rocky Mountain Region and this is a talk that we gave at QADS on the latest developments and clinical applications and uses of SGRT. Before we get into the talk, these are my disclosures and the survey of topics that I was asked to cover was the availability and accuracy of different commercially available SGRT systems. The implementation strategies to avoid mistakes when implementing a new SGRT program as well as how SGRT system data can be used in various clinical ways. So that's includes process quality improvement, training of your staff, margin determination during planning for certain types of treatments, characterization of immobilization requirements, patient compliance and new program for new programs like single ISO center, multi target SRS. Things like novel uses like masks, head, neck treatments, SGRT data, margin determinations for things in the SRS realm and what those goes into. Those martial determinations for things like multi target SRS. Some disclaimers. Not all systems are equal, they all have different features. A complete system review. So if you are looking there was a probably 8% of the audience is looking to potentially implement SGRT at their clinics. So a complete overview of the system and their feature should be used before selecting a system and not all features in this presentation will obviously be available on all of the commercial systems that are out there. That being said, TG3O2, which is the current task group compliance protocol for these types of systems lists the table of kind of specifications for each of the commercially available systems. This is a summary slide of the commercially available system. Some of these are not in three O 2 because at the time in February, some of these didn't have FDA clearance since February when when this talk was originally given. The Luna system has received SDAFDA clearance in the United States. So it is available in the states here. But Luna is is a lap product. There's a single camera system from Brain Lab, the identified product from Varian previously Humetic, the Catalyst system from C Red's been around for quite a while. And the aligner T system, which happens to be our system here at Advent Health is the system that we standardized on from Vision RT. And the Accutrac system is is kind of unique system. It's it's currently still not FDA cleared here in the States. There is some information about it and all of the vendors do quote that they do interact or at least have some sort of connectivity to the linac. This is based on vendor statement. This is not based on actuality. Some of these interfaces are still within the work. So Luna and Accutrac specifically if you have Varian Linux or response interfaces for Electro Linux may not be actually commercially available just yet. Commercial features vary by vendor. All commercial systems quote less than a millimeter of positional accuracy. So very precise systems, but they are subject to the design specifications for those systems. So things like Catalyst or Identify will have a specification that says less than a millimeter. You do need to check exact track. Same thing if that specification is based on the fact that with the exact track system, for example, that's in conjunction with the X-ray system. So medical physicists do need to kind of verify that these claims are true based on the utilization pattern that you plan to use. And the design decisions by the vendor will dictate what your quality management program looks like to verify some of these specifications as well. When you select a system, you have to build kind of what your SGRT process or your patient process is going to look like. So for just context in this talk, this is Advent Health's process. We use the SIM RT product from Vision RT to acquire all of our 40 CT simulation traces, do our breath hold coaching and brothel CT Sims at the time of CT simulation. That process moves into planning using a new product called Map RT, which is a collision collision mapping software that uses two additional cameras in SIM to capture the entire surface of the patient from the head to toes, including all of the immobilization and Mary's that capture with a Lidar model of your treatment machine so that you can map out the collision solution space within the room based on ISO center location. This allows us to do a lot of advanced non coplanar types of treatments as well as moving into things like the work from Key Shen on the the four Pi non isocentric types of delivery for very complicated lesions really close to critical structures like the heart, brain stem, optic apparatus and things like that where you want really steep gradients. And some of these non isocentric treatments can achieve that. Traditional SGRT. What people usually think about is the SGRT implementation at the treatment machine. For that we use a line RT, which is what you would traditionally think of as SGRT. We use this on 100% of our patients census. Everything from heterotropic bone ossification all the way to trigeminal neuralgia, acoustics, AV, Ms. all kinds of different things, but it is the sole positioning technology that we use. We don't use tattoos, we don't use marks, we don't use any of that. We use a liner T on 100% of our patient census across Advent Health in the Rocky Mountain region. What we've added to this at the time of treatment is a shrink off imaging system called DOS RT. This is a way of visualizing the treatment beam during delivery and we'll talk about that towards the end of the talk as far as advanced new features. And the system is also used for biometric facial identification. So all of our patient treatments are tied to their biometric facial identification. So their biometric signature is the hard stop looking at moving up that hierarchy of effectiveness. Instead of using administrative controls like name, date of birth and what are we treating today, we're using the biometric signature to unlock that treatment for delivery at the time the patient walks in the room. We also use it for respiratory gating and a number of other more advanced features for SBRT of various sites in and around the diaphragm. What this gives us is one environment fostering innovation across that platform, improving the patient experience by giving them a uniform experience of expectations as they enter our clinics, as well as increasing the quality, safety and efficiency of our deliveries without sacrificing different things along the way. We have this one platform that we can work on. It's very analogous to our one varying platform that we use for treatment, treatment delivery as a treatment machines, but also treatment planning and the OIS. So depending on what your philosophy is, as far as if you're a single vendor type of person, which I am, Full disclosure, I like things to be integrated as well as possible so that we can continue to move through that process in a more efficient way and also give that patient a uniform experience as they go through it. So this is how we built our SGRT process. You might build it completely differently, but this is how we've done it here at Advent Health. And a lot of the things that you'll see are based on kind of this integration pattern that you see on the slide. When we talk about implementation of SGRT, one of the things I was asked to talk about is the implementation. How can we avoid making mistakes? There's the traditional commissioning aspect to SGRT plans, our SGRT programs where we're, we are doing a Commission that includes measuring the system accuracy, terming the system limitations, developing our operating procedures, developing our quality assurance schedules and all the things that we traditionally think is commissioning. But in SGRT, we also have this ongoing commissioning that we call performance validation. And this concept comes in, in the predecessor to TG3O2 and TG147 of this idea of validating the system performance under new body sites, new treatment modalities, new treatment techniques. And good examples of that are things like DIBH for breast. If you want to move into DIBH for SBRT, there's some performance validation that needs to take place, which is kind of like an ongoing commissioning of the system to make sure the system operates in a, in a proper way under. So you think about DIBH and a lot of people are doing combium CTS for DIBH breast, but you are going to do DIBHSBRT. So you are going to have a combium CT. And if you have something like a variant platform that requires some sort of count centering, that's going to change your process away from that breast and you need to make sure that the system will operate effectively underneath those new conditions. And so that's kind of an ongoing commissioning and that's largely done by the physics team, but also we roll in our therapy and just symmetry teams as well because we're using STRT across that entire process. The implementation strategy, this is largely looking at from nothing to using this in a in a kind of a full capacity from our aspect of 100% of our patients, we try to implement about 20% of our patient census at the go live. So very easy things, right Breast, whole brains, every vendor will have some sort of on site training. They do it in different schedules depending on which vendor you go with. So sometime after post on site training, we moved to about 50% of our census. We roll in more complicated treatments like the IBH bone, breast, maybe lungs and prostates to get a good smattering of different body sites and regions. And this is going through AQA process. So these icons showing the hierarchy of effectiveness, we're going through the QA process. We maybe do some additional staff training identified by the little man here. But as we go through our QA process, we're we're developing our skill sets, we're gaining confidence in the system. And then by the time we've done this and we have a good process for implementing new sites, we then move on to 80 to, you know, 100% of our our patient census. This includes some more advanced treatments when we built confidence in the system like SRSSBRTDIBHSRT and those types of things. The progressive implementation helps us build that expertise as we go through the process and that expertise builds confidence in the staff and then confidence accelerates the adoption process. The worst thing you can do with SGRT because it is very different than X-ray imaging is to drop it on a staff and say, godspeed, we hope it all works out for you. The, the, the adoption after that, that type of implementation tends to go down. And actually, I see a lot of SGRT systems that are hanging from ceilings that are never even turned on because they had a quote UN quote fat experience when they tried to implement it. So we use an onward and upward build out, build up type of approach where we identify a new application or a treatment site, we work out a process map and identify areas of concern from purely theoretical standpoint. We then move a phantom with the staff through that to make sure the physics team is understanding what the therapy team is going to do in implementation and work out any kinks there. And then after implementation on live patients, we, we put this through our quality assurance process, add that to our training material and make sure that we're addressing any adjustments may be needed as we go through this. And we do this for each treatment site as well as each treatment technique that we're adding to our SGRT program. Again, looking to build on that expertise and increase our, our confidence in the system as we move through. So our observations in implementing SGRT has been that it harnesses the information that it provides to more effectively treat all of our patients. It enables us to objectively review and then improve our current treatment process. And the SGRT has implications far beyond as you saw in our implementation, just treatment, it can be used throughout the entire treatment chain end to end SIM planning and treatment itself. And then SGRT is being used at our sites. It says it can be here, but it is being used at our sites to minimize the impact of treatment on our patients. We're, we're having much more fast and effective treatments for these patients each and every fraction so they can get back on to doing things that they love in their lives rather than focusing on treatment every day. So some of the things that we've rolled into our SGRT program is using the SGRT data for margin and body site planning techniques for margin determination. This paper here quoted came into 2014, which is going on a decade old as of this month. It was actually a very interesting paper where they looked at extremity sarcoma and PTV margins based on the SGRT output. This is SGRT data for SBRT lung looking at rotational translational uncertainties. And we can look at this over a large popular population of patients to 300 patients and say, OK, what is our immobilization strategy? How is that impacting SGRT T shifts? We're seeing information to better determine lung lung SBRT margins. Are we doing a better job at site A versus site B? Do we need to look at margin determination at a site A? Do we need to do a peer-to-peer staff training? Do we need to rotate therapist at SIM to make sure that our immobilization systems are appropriate for these body techniques? Because we can now live real time quality manage these things by looking at the data on our patients from fraction to fraction. A great example of this, you can look this up on the sgrt.org. These are free talks that you can go and look. Both of these talks came at the European Union SGRT meeting. Both of these gentlemen do yeoman's work. As far as the big data analysis of the SGRT data that comes out. There's an absolute blood of data that we can be using that kind of falls by the wayside because we think, well, they didn't move during treatment, so now we can move on to the next day. We can actually now use that data in a big data context to actually use margin determination in our planning to say these margins are appropriate not just based on our physics ability and our physics determination of accuracy of the system, but also on our therapist training their ability to fabricate immobilization. And this is what the end result is and this is what our margins should be based on those end results. So very good talks. Something I would recommend looking up and a good example of what we've done with that data is our data-driven immobilization. So by using STRT data to drive a mobilization requirements, we can transition from rigid requirements for immobilization where we're physically limiting a patient's ability to move to more of a postural correction and asking a patient to work with us to avoid some of these less than ideal rigid immobilizations that tend to lead to poor patient experience. One of those examples is head, neck. So 15 years ago, 16 years ago almost when we put in SGRT, we were using the traditional full face masks. As of 2013, roughly we went to exclusively open face masks for comfort and ability to position patients. By 2017, we were expanding the SGRT utilization by looking at our data and saying we don't really need to originally immobilize some of these patients, especially our claustrophobic patients. We can have these open cranial vaults, open shoulders and correct their posture because now with VMAT, we can actually correct that posture, which has a higher impact on the dose distribution than say minimal weight loss because we're now delivering beams from all around the patient. And now 2019 and beyond, we can offer patients what we're calling minimal mobilization or maskless head necks. And we have this these simple chin straps. These chin straps are there more or less for the therapist to make setup more efficient so they can set up a patient in less than two minutes rather than trying to fuss around with kind of the complex 6° of freedom that the head and neck region allows for. This gives you basically a good anchored starting point and then it's relatively loose. The patient doesn't feel confined in it, but then you can actually manipulate their shoulders, their head and things like that, starting from a place that's very close to ideal. And so this has led to unbelievable improvement in patient satisfaction. We don't do it on 100% of our patients. Obviously, there's patients that that still need masking. So you see the the three masks here toward the right, those are still used in regular practice in our centers, just depending on patient compliance and patient selection criteria. Once you're looking at your immobilization, you can start doing interesting things as far as looking at plan specific margins. So in this case, this is a single ISO center SRS where we took the QA phantom and actually fused it into the orientation of the patients in their immobilization. We ran a plan Pacific QA on it and then we looked at the trace for patients post QA. You can see that they look very similar. And if we do a feature based registration of these things in time and beam geometry, we can see that they overlay almost ideally this entire vertical axis is 1mm. So everything was within SRS tolerance, but you can see the last two beams are delivered and they're closer to the 1mm tolerance. This was a way that we were able to identify some camera characteristics, some intrinsics of the camera that needed to be better calibrated. Once we were able to calibrate at these beam angles and take out some of those intrinsics, these things drop down to more of a less than half a millimeter type of tolerance, which is what we like to see for our Sr. S S. But this is ways we can look at if, if this is unavoidable. You obviously don't want to correct for this if it's a false positive, but if it is a true positive, you want to be able to correct for this, but you also want to account for the uncertainties. So you may want to add a little bit of margin to your patient in this specific plan orientation. In this case, this was a complicated ISO center placement that resulted in part of the the patient's ROI being off the sensor completely because of the orientation of ISO relative to the targets we were treating in the cranial vault. A way to build the confidence that we talk about of gaining expertise is to do follow up imaging on your patients. This is a very simple 4th ventricular MET in the in the high vermice next to the brain stem. We do regular follow up on some of these patients who have ongoing Mets. This is a breast patient who's been in for seven different SRS fractions I believe at this point since February. I think we also treated her, but this is her plan MRI, this is her three month follow up MRI here where you can see, you can see the results of the radiation and the and the diffusion imaging, but you don't see any significant scarring. This patient was actually repositioned using STRT during delivery without extra additional imaging. So we were interested to see how well is the system actually doing as far as the precision that we quote to our physicians. So we have a nine month follow up and then I believe, I think a 15 month follow up MRI showing some radiographic scarring, but no radionecrosis and no radiographic scarring on the brain stem at all, which is a nice thing to see since we're trying to build our confidence in the precision of these systems. Another area that we treat very routinely is trigeminal neuralgia. We call them Trigem Thursdays here. We do probably 2 to 3 trigems a week. This is a very well known Gamma Knife paper talking about the increase of signal from the trigeminal nerve after Gamma knife treatment of that nerve. So we decided to look at this on follow up with our patients. This is one of our left trigeminal nerve patients that we treated with a 4mm cone SGRT for positioning, fine tuning with cone beam CT and any realignment using SGRT. And we see again that that additional signal in the trigeminal nerve post treatment indicating the targeting was within the the 1mm width of that target. And so again, these things allow us to build confidence in what these systems are achieving. And so we can move into these more complex beam arrangements and planning techniques like single ISO center multi target. For single ISO center multi target, we know that very small rotational offsets can cause big translational offsets at the target locations far from ISO Center for small tumors. This is a very real issue and systems like a system checks like wins and lots at ISO center don't really translate to those locations like we would like them to and so the SGRT system can be used to evaluate this shameless self promotion. We did publish a paper on this last year for an off axis wins and Luts using any commercially available or self designed 3D printed, made by hand type of phantom. And this allows you to isolate mechanical verification and patient verification. So the mechanical checking for isolating those mechanical errors versus the patient errors is very important for these types of treatments. I won't go into the mechanical stuff. There's simulations that we run to look at mechanical errors. There's also tools that are out there like the ISO point tool and things like that where you can actually physically measure these things. Now using optics similar to the FDRT systems, They're actually incredibly interesting. So I encourage you to look those up where you can actually physically measure these and compare them to your simulation. But in this case, we rerun a phantom to a known geometry. We apply those mechanical uncertainties and generate off axis wins and less images that are virtual images. So we can evaluate what our machines should be achieving at these off axis locations. We can also do that though using the STRT data, the topic of this talk for the patient specific errors. So when we're implementing tolerances for our STRT systems, we're implementing them at 1 millimeter, 1° at ISO center. But what does that mean for a target that's 8 centimeters off axis? And so we have this simulator where we can actually put in the target size, the margin that we plan on using, the location of the target relative to ISO center where it is within 3 dimensional space, whether it's an absolute position or a relative octave within the coordinate frame. And then we can put in some simulation parameters for accuracy, resolution and those types of things and run a simulation. One of the nice things that we can do now is take our STRT data and enter the tolerances that we want to treat at at the time of planning. So if we're going to use the, the kind of what I would call the vanilla standard 1 millimeter 1°, which is what everyone to use, we can set 1 millimeter 1° in the in the simulator, we can set some resolution. So in this case, we're using a 10th of a millimeter, a 10th of degree of a sampling resolution. And we can run a simulation on what does our margin need to be for this target if that's what we're going to use at the time of treatment. The nice thing that we can do, though, is we can put in these probability distributions, and the probability distribution essentially just says anything from -1 millimeter to 1mm is equally probable for lateral motion, for vertical motion, for longitudinal motion, for rotation, whatever it is. If we want to say all of those are equally probable, that's totally fine. We might not have any data to run on. But if we do have a history of using SDRT, as we do here at Advent Health, we can actually take the last 100 patients and say, I can look at the probability distributions. What is the probability that a patient's going to have a 1° rotation during treatment? It's very, very low. And so I can import those probabilities from a population of patients for my real clinical situations. This incorporates my staff's ability to deliver the treatment, their ability to fabricate the proper immobilization, our ability to do the proper QA on the couch, and everything else, because the STRT system is measuring this over a huge population of patients. And so we can import those probabilities and run the simulation for our site specifically and see what that does for our patient errors and what that means for margins. And what that does is we run a simulation. You can see here in the top row up here, you can see the dimensional offset. So this is the distance offset graph, what we call this the overlap percentage or the coverage graph. You can see that the coverage falls to 0, the dark blue very rapidly compared to the distance. And then if you add a margin, you increase that hot center, which means you have some wobble around that target. By increasing the margin, you can increase the 100% coverage over time. And then you can look at the three-dimensional distribution of what this looks like. And this is where the SGRT data gives us interesting results. So what you see on the left is 1/2 centimeter target, 8 centimeters off of isocenter. The solution space is not what we would expect. It's not a sphere, it's not a spheroid, it's not an... It's, it's essentially this, this very complex 3 dimensional shape that says, OK, if I have a 1mm, if I'm going to allow one millimeter, 1° at ISO center, this is the distribution of positions of my target 8 centimeters away from ISO center. In this case from this SRS plan, if I wanted to cover 100% of these positions, I would need a 4mm margin. That's a lot of margin for an SRS, especially if you're trying to keep your, your V 10s and your V twelves down. And So what we've done is on the right, we've imported the probability distributions from a hundred of our SRS patients and said, OK, what is our site able to achieve given 100 patients now treated with SGRT? And you can notice that the solution space in 3D looks very different than the total solution space. Ours looks more like a cube. And what that says is we have very low rotational uncertainties at our center and that allows us, if we want to cover all of the possibilities of our center, we only need a 2mm margin. So we've cut our margin in half for multi met targets by just simply looking at our SRT data and saying what can we achieve with our masking system, with our staff training level at this institution. If we're going to roll out multi met SRS to another institution, we now have a baseline of what to shoot for. And if we see a difference in the distribution or we see a difference in these 3D solution spaces, that may be a training requirement that may actually be some sort of commissioning requirement. And we can investigate that in a finer detail at that institution before rolling that program out. This slide, because of the resampling for this platform for this webinar, is a little hard to read, but essentially this is just showing that the coverage with a 2mm margin on a target at one institution can be 100%. To the lower end of this is about 50%, meaning that about 50% of the target is missed with a 2mm margin. Whereas at a different institution applying their probability distributions with a 2mm margin, you have 100% and the low end is around 80%. So a 2mm margin might not be enough, but it might be enough to get you most of the the probable positions that you're going to see during treatment. And what does that mean from an SRS standpoint? And that's a whole nother discussion that we can talk about from a statistical standpoint. But you can see that two different institutions can have two different covered statistics with the exact same 2mm margin. So it's by far not A1 size fits all type of solution that you really do need to be looking at this data on a on a planning by planning perspective at your institutions. So SGRT data has a lot of different things that it can offer you if you're willing to use it at various stages of planning. And so for the last 5-10 minutes or so, I just want to cover some advanced uses of SGRT. Talking about shrank off imaging, this is something that we've implemented in our centers since about October of last year. And for those of you who aren't familiar with shrank off imaging, shrank off radiation Tankoff who discovered this effect. And by a charged particle traveling faster than the speed of light in the same medium. So light, say in water, because of index of fraction that creates a polarization and that polarization when it relaxes releases a photon in this green, blue spectrum. So what you see in the background here is the IAEA website view of a nuclear reactor. This is a very common image that we see when anytime there's a disaster like the Fukushima disaster, you see this eerie blue-green glow. That glow is the tranq off radiation actually taking place. And we can actually utilize this effect on our patients. And So what we've added at our institution is this DOS RT product, which is a series of tranq off imaging cameras, which is a camera that has an image intensifier between the lens in the chipset to allow us to intensify this very low contrast signal. So the signal to noise is very, very sensitive that we're we're trying to work with here. You're dealing with light contamination and a number of other things. But once you get this dialed, then you can actually visualize the beam on the patient during delivery because of the trink off effect being emitted from our patients. And so this allows us to do a lot of entering quality assurance and different things moving into the future that this this new imaging opens up possibilities of. So what this looks like at our center here at Parker is we have our standard SGRT cameras, our horizon cameras from Vision RT. We then have our Trank off imaging cameras looking at ISO center and then we have the Varian NDI or RGSC camera that comes with a variant true beam. So we are camera rich here. We have lots of cameras hanging from our ceiling, but they're all performing slightly different tasks. And So what we've got the system back in October of last year, we wanted to Commission the system and there's not a lot of guidance on that. So what we wanted to see is can we look at low levels of stray radiation. So what you see in the right here in the video is a deliverer of a picket fence under Turing cough imaging. If you look at that in a film in the upper left of the portal imager in the bottom left, you can see this additional dose. That dose is actually under the wide jaws. The wide jaws are closed down to where you see the MLC leaves. But this scatter dose is a result of the geometry of the variant head and this is a known effect. We actually documented this effect for variant and wrote an STB. They now have a new product number for it came out 2013 many years ago. It's actually an official release now for customer release that you can download. But this effect can be seen even though you can't see it in the video, when you look at the composite image, you can actually see this effect underneath the Y jaws. The reason why that's important is your planning system cannot account for this dose when doing the dose calculation because it's a head geometry issue. And so one of the applications of this that we see is in recurrent head neck, so retreatment of head and neck modulated fields and those can result in a high modulation factor that then will allow for the scatter dose underneath the wide jaws to impact the quality of treatment to run that field on a plate that allows for drink off imaging. We can then look in the regions underneath the wide jaws and make sure that we don't have this low level of dose that we are concerned about. And if it's OK, we can move on to more of a standard QA and an R check, a map check, you, you name the check that is is good for you and what device you're using. But you can do that standard check and then you can also validate on the patient during delivery. So in this case, if we don't want to see entrance and exit through the shoulders, we can check the shoulders. If we don't want to see entrance or exit through the parotid gland, we can do that. If we don't want to see entrance and exit through maybe the contralateral side of the head or through the oral cavity because all of those were taken to 70 Gray with their current course of treatment. But we can actually validate that live on the treatment to make sure that the planning parameters used in the avoidance sectors are appropriate for this patient. We can see that there's even though we're not entering editing through the mouth. You can see some Trank off signal there and we'll talk about that here in a moment. The other thing that we know is from the Frank and Tam equations. Frank and Tam got the Nobel Prize with Trank off in 1958 for proving that the shrink of yield of light emitted from a material is proportional to the dose delivered to the same material at that location. And so we wanted to check the validity of this assumption. And we created these calibration files, one with ML CS on the left, one with standard jaws on the right. We wrote some software or some code that would pull the drink off, signal off the images, graph that in 3D and also look at it the linearity and you can see the linearity of these measurements are extremely linear, which is exciting for those of us who would like to potentially use this as a dosimeter in the future. So this is encouraging result from a commissioning standpoint that the system is operating in a way that we would expect. You can use this for potential quality quantitative applications. This is from a paper in 2020 out of Dartmouth where this was the most downloaded paper of the year from the Red Journal showing this dose on an SRS. And if you have these calibration files, can you linearize the dose coming off of a patient and potentially use the patient as their own dosimeter? There is a PhD student who just was awarded their PhD just here back in the spring, who actually linearized this dose on patients using 3 channel color cameras to correct for the melanin content in the skin. So this, this, this is an active area of research and actually very interesting what's going on in this field. There's potential quantitative applications using non biological materials. We know the light piping effect of acrylic. We can see the same light piping effect on bolus. We can see the light piping effect. That's what we just saw in that head and neck. In this case, the bite block is an acrylic bite block under the oral tongue, keeping it away from the floor of mouth, which is where this gentleman recurred. And you can actually see the light photons being piped up the acrylic block out of the mouth leading to ability to maybe remote sensitive symmetry using that signal at the PTV, which is not visible to the camera. And another paper that I think this is out of view pen. But the use of these scintillating dots as a higher yield shrink off signal to then do remote dosimetry sensing on breast, a total skin electron and a number of other applications. So a lot of exciting things we wanted to try to Commission this effect. So what we did is we actually purchased a 20 centimeter acrylic rod. We covered it with a black cloth. We're actually a radiating 20 centimeters from what you're seeing here in the video. And that photons are then being light piped down this acrylic rod. And we're going to try to use that signal and see if the linear dose can be achieved 20 centimeters from the actual irradiated volume. If we do this, we can look at the composite image and this is going from 25 centigrade to 30 or 300 centigrade. And if we look at the linearity of the signal, this as well looks extremely linear even though we're 20 centimeters from ISO center. So if we look at another treatment some days later, some higher dose treatment some days later, we can see that not only is the signal linear, but it's also very reproducible. So this lends itself to possibly some machine UA applications in the future of checking daily dose output. We have all of this. What is this utility on patients? Oh, before we do patients, just some cool stuff, non biological materials. You can introduce defects. You can think about adding a glass fear to a defect. This is a very clear piece of acrylic with an electron tree in it. We irradiate this. You can see both the light piping effect, this little hat on top up here, But you can also show that the defect reflecting the optical properties. You can actually use the defect as a pseudo dosimeter. So just just a cool aside there on patients though, this is where we're finding the utility. Even since February when I gave this talk originally, we probably had 15 to 20 additional cases of different ways of using this for our whole care experience is what we call it. So we can look at a plan from Eclipse, look at the entrance and exit shapes and we would expect to see dose. We can then have our therapist visualize that dose live on the patient during delivery and then we can also inspect the composite dose on the patient at the end. An astute therapist brought this to our attention that if you were very close and looking at the very first frames of the video, you see this frame where there's a flash of dose across both breasts. This is a 36 year old female going D IBH for left breast treatment. We're trying to block her heart and all of a sudden we see this flash of dose across the contralateral breast. What this ended up being was a errant port film technique added to this patient. Instead of using the breast technique, they accidentally selected the pelvis technique, which means this is a 40 by 22 field with a single monitor unit. So we can see one monitor unit being delivered through that open port. That's obviously less than ideal for a young lady. And so this was corrected after the very first fraction and she did not get any additional dose to her Contra lateral breast or her heart or her lungs because the drink off imaging system was able to catch something that we would have never seen in any other fashion during delivery. If you have astute therapist, this is a delivery on a 99 year old woman of fungating mass on in her breast tissue, partial bolus placement at the time of SIM just over the mass. But we also had to do IMRT delivery because she has a frozen shoulder and a frozen elbow. So what that means is we're trying to avoid a radiation of the IPS lateral arm while also delivering the dose that we need to the treatment area. If we look at the composite dose image at the end, we can see the bolus placement. We've written some software that can actually do some edge detection and make sure that this partial bolusing is taking place in the right portion of the field. Because this is an IMRT. We're optimizing based on where this bolus is placed. And so if there's an improper bolus placement, we can flag that treatment and make sure that we adjust that with the therapist or address it via an alert saying, hey, make sure the bolus placement is in the correct location each day and per the SIM photos or whatever we're using for that bolus placement. So another interesting application and we've had application after application on our patients. Here is another application. Just one more before the end of the talk here. This patient actually, unfortunately, we only caught her last three fractions. And what was going on with this patient is we had multiple peer reviews. Her poor films look fantastic. She's a double mastectomy, double reconstruction patient, but she's getting this very acute reaction. You can see in her armpit and axilla area. And we were unable to determine why this was the case. Plan looked fantastic. SGRT tolerances look fantastic. We analyzed all of her SGRT fractions. She was well within all of our tolerances. And so for her last three fractions, we happen to have the trank off system commissioned at that point. So we turned it on to see what we saw. And this one on the left is her third to last fraction. We imaged her with trank off imaging and everything looked as expected. So we were just absolutely befuddled. Why are we seeing this reaction for second to last fraction however it look like this and so on the right here what you see is the flashing of the superclab dose and the PAB dose through the axilla overlapping with the tangent fields and what this was a result of was a .3° roll of this patient. Our SGRT tolerances are statistically derived and we we basically allow for a two degree roll and that being statistics is good for about 98 to 99% of our patients. She happens to be in that other 1% and so a small .3° roll showed a non robustness of our plan to that roll which allowed flashing along this steep acute slope under her arm. And we went back to review this because it was at this point too late to correct this plan. But looking at it from approach or a retrospective way, all we had to do was move 3 MLC leaves into this field. And had we seen this on our first few fractions, we could have moved those 3 MLC leaves into this field and she would have been robust to about a 1.5° roll. And so she would have probably not had this reaction. And so we use this as a jumping off point. This was presented in February. We have now made active plan adjustments to patients based on the trank off imaging of just minor robustness changes that need to be made to make these plans more robust to patient compliance and patient body morphology. Just various different things that we can see now with the shrank off imaging and the service guidance system knowing yes, they're in the right position using SGRT, but also the shrank off imaging is telling us that they are actually getting the proper delivery of the radiation at each and every fraction. And so in summary, there are a number of commercially available SGRT systems out there. That's up to the physics team and the clinical staff to see which one best suits your desires. The desired functionality, accuracy and level of integration should be evaluated. Good implementation strategies will build confidence, and that confidence will build expertise, and that expertise will aid in your adoption of these technologies in your clinic. Both commissioning and ongoing performance validation is a critical component of any SGRT program. And then observer based natures of SGRT systems provide data that can be used for a variety of processes, process quality improvement, training of staff, margin determination during planning and characterization of your mobilization, staff competency and patient compliance. New innovations with SGRT technologies are open to new are opening new ways for us to view our quality management programs and increase the quality and safety of our treatments each and every day to our patients. And then new SGRT technologies are showing significant promise far beyond simple patient monitoring and patient setup. Things like identification of procedural and delivery errors like that port film that was added inappropriately. Collision mapping at the time of planning to allow us to do more complex but more safe treatments by allowing us to do virtual dry runs before the patient is present. Dose monitoring for both qualitative and quantitative applications on our patients during every fractions. And then in the future, potentially machine performance checking using these non biological materials and shrink off imaging in the future. And so with that, I'll say thank you. And then I guess we're going to open this up to questions from the audience. Thanks, Mike. Appreciate the presentation was well received at QADS and I think it's been well received again today. We didn't have quite, quite the audience. If you do have questions, please go ahead and type those in the left hand side of your screen. You should see a questions box where you can enter in any questions you might have and we will take a couple of minutes and, and get to those. I want to remind everybody as well that we do have some upcoming best at QADS series webinars coming up in the month of October. You can find those on sunnuclear.com underneath our webinars tab. So please join us for additional presentations from the meeting in Portugal earlier this year. There is a question like obviously some of the stuff you presented at the end there in the shrink of imaging is, is quite unique and and very interesting. There's you were wondering kind of the idea of how do you actively adapt those plans and what's the process that you step through in your clinic to to adapt those plans when you see something you'd want to address? Yeah. So a good example was that 4 field breast, the last option we saw Or even the lady with the frozen shoulder and the frozen elbow, those plans with challenging body habitus is, is one of the things that we see a lot of with shrank off imaging. And So what we'll we'll find is we've had compliance issues where we have heavier set patients who are non compliant. So we have a patient who just underwent a plan adaptation. She's getting high tangents for for breast in this case and she's tucking her chin and she is showing a radiation that's hitting her chin. And so we actually use that in both a plan adaptation. So making the plan more robust to her non compliance while still covering the target, but also using that to then be part of her weekly assessment with the physician and explaining to her visually, this is the the consequence of you not raising your chin on a daily basis. This is this is imaging of the the radiation actually clipping your chin. Now it's not detrimental for one fraction, but we can use that in both patient education to augment how the plant is being delivered through compliance. But we also go back and we can roll that back to dose symmetry and we can move the jaw maybe down a little bit. In the case of that four field breast, because of that steep slope, we just moved 3 MLC leaves into the field and that makes the plant more robust to small patient variations. The case of the patient that had the partial bolusing, if we're doing an IMRT based on the optimization being where the bolus is and the bolus isn't in the right place, we're actually adjusting that dose to the patient by not placing the bolus correctly. So if we need to open up that bolus, change the bolus from what was SIM, we've actually augmented boluses for we have these very complicated post surgical reconstruction head next where we're seeing that we're just having issues with this. Another big thing now in the days of VMAT, we use a lot of avoidance sectors and these no entrance, no exit types of planning optimizations. And that's very dependent on the patient's anatomy being correct at the time of treatment because that avoidance sector is only accurate for the geometry that you see T For example, if you have a thigh sarcoma and the thighs are too close together, your avoidance sector will actually result in clipping of that contralateral thigh. And if you're going to 60 grade, you can get a lot of dose to that contralateral leg. And if we see that we can actually make adjustments to some of those avoidance sectors to make them more robust to contralateral leg position and things like that. And so we're making those plan adjustments now based on what we're seeing actively in the first few fractions of drink off imaging. Thanks, Mike And QADS in Portugal, there's quite a few questions about when using the STRT in the modeling you've established looking at the prediction of margins, you know, determining it based on the site or tumor volume or ISO center, How you go about doing that and identifying how you want to adjust any of those margins. I know you hit it on the talk, but is there any additional learnings that you had since February? Yeah, we're, we're always learning something. We get a lot of neurosurgeon, new neurosurgeons. We have a big neurosurgery group and so that, you know, neurosurgeons are very fond of 0 margin. And so we, we, we do what we call a dosimetric margin when we don't put a margin, I, but we make the dose a little bit more broad, But so there's a lot of different things that we can do. But I, I think the neurosurgeons and especially the radoms, when they see, OK, the STRT system is giving us a live quality assurance feedback of what the patient's doing during delivery. And So what they see is, oh, I see a static image and what I'm doing surgery, I can see you can actually see that the patient is maybe moving it's sub millimeter. But we can see them moving underneath these cameras and what we have a hundred of those patients showing that this is a very consistent phenomena that these patients aren't perfectly still, they are moving a little bit. And when you treat something 8 centimeters away from ISO center or five centimeters away from ISO center, when we can show them the consequences of those very small movements are not totally inconsequential. They're much more apt to say, OK, do you run this through and just tell me what margin you would predict based on this center's capability and the immobilization that I should be using? And then sometimes I'll be like, I agree with that, I disagree with that. I want to change this. And what it does is it makes a very rapid procedure. Instead of having to have that conversation every single time, we can now use the STRT data and say, this is a historical perspective of what we are able to achieve using our skill sets and our live data. And this is what your margins need to be based on that data. Now you're the, you're the doctor, you can do anything you'd like. And they sometimes make adjustments, but they find more and more that is we add more data to that data set and then that patient falls right into that statistical range. Like, man, this is pretty cool. This can tell me exactly what I need to do before I need to do it. And so they're, they're much more warm to the idea of adding that margin because they they not only think it's a theoretical margin for setup, they're now seeing that that is a real margin to cover a real phenomena that we are measuring in real time on every one of our patients. And every time we measure a patient, it goes into that data set. And we're refining that big data set each day to give us better and better margins. And so that's what we're doing since of February that just keeps we're adding to those data sets. We're adding to their confidence in us that we're not just, you know, picking these numbers out of the error based on some equation that we developed from our commissioning data. A lot of times, you know, physicists are seen as though you cranked out some numbers of commissioning and that's just applies to everything. And it's that my patients are unique and we're all delicate geniuses. So now we have a way of looking at every patient and saying this is this is reality, this is what we're doing. And so I think it's a little bit more well received because it's real data on real patients. Wonderful. Well, thank you again Mike for the presentation and and joining us at both the QADS and again today and reprising this again, I do want to thank everyone for attending today's webinar and I wish you the best of the rest of your week all. Right. Thank you. _1734781469528