entitled Radiation and Fluoroscopy Safety in GI Endoscopy. You will be able to submit questions and comments throughout the event via the Q&A box. The Q&A session will be held at the conclusion of Dr. Kwok's presentation. My name is Eden Essex, and I will be the moderator for this session. A recording of tonight's session will populate your GI LEAP account when it's available next week, so you can review the content anew or watch it with others. The objectives for this session are to list the three pillars of radiation safety, recognize best practices in radiation protection of patients and staff, and finally, to identify best safety practices your individual interventional endoscopy teams should deploy based on local factors at play. Now it is my pleasure to introduce our presenter, Dr. Carl Kwok. Dr. Kwok is an interventional endoscopist with Kaiser Permanente, Southern California. He is a member of the ASGE Quality Assurance and Endoscopy Committee and lead author of the ASGE guidance paper addressing radiation safety and fluoroscopy safety in GI endoscopy. I will now hand the proverbial floor over to Dr. Kwok. Thank you so much, Eden, and thank you to the entire ASGE team for putting together this hopefully very informative Thursday Night Light seminar. I'm absolutely honored to be able to talk to the group this evening about radiation and fluoroscopy safety in GI endoscopy, and I have nothing to disclose. So by way of introduction, this topic actually started a little over two years ago, if not a little bit longer than that, when during one of our quality committee meetings, a question was raised about just the standards of radiation safety training in the United States, and I personally interjected. I said, well, my training consisted of two things back in the Stone Ages. One was to wear lead. Two was to hit the five-minute alarm to silence the radiation alarm. Obviously, there's much more to radiation safety than that, and that actually sparked what ultimately culminated in our scientific review that was recently published in Gastrointestinal Endoscopy, and so we figured this was a perfect segue into tonight's talk. I was very happy to see that several course registrants tonight are actual interventional endoscopy fellows, and so I am especially honored that you are taking the time to join us tonight because, as you may know, radiation exposure is cumulative over one's lifetime, so that earlier on in your career that you are cognizant of these issues, the better you will be in the long run, and so I've broken up this talk this evening into six parts. First is a brief introduction of the issues at play. The second is, of course, the very basics of how a fluoroscopy machine works, and I think that's essential because you have to understand how the machine works on a very basic level to understand the factors that impact image quality versus safety. Next, we'll transition to radiobiology, and then followed by occupational dose standards and limits. We will spend some time as well talking about special populations such as pediatric and pregnant populations, and most importantly, last but not least, we're gonna end the talk tonight by talking about practical tips and strategies on how to protect the patient and the staff. So again, the purpose of tonight's talk is really to educate and inform our target audience. It's really not meant to scare, and the reason for this is it's important to note that radiation, believe it or not, is actually part of our natural daily living. Radiation exists in many arenas and venues and forums outside of the ERCP room, in the event that you didn't know that. So for example, cosmic radiation, next, can happen simply, for example, by living west of the Rockies. The land elevation generally is a little higher west of the Rockies than it is on the east, middle, midwest, and east coast. And similarly, flying, as this picture shows you, on average gives about a 0.1, a zero one, I should say, millisieverts of cosmic radiation per hour that you're up in the air. For other individuals that live in other parts of the United States, there is something called a radon belt, where there's naturally occurring radon that comes from the ground, and the belt typically extends from approximately the state of Utah to approximately the state of New York. And in fact, there are some areas, if you look at the EPA heat map, which may have ground radiation of four picocuries per liter or more. That's something that you can't fix. I mean, that's just, this happened over a millennia. And so, but that's just an example of radiation exposure outside of the ERCP lab. And of historical note, I mean, fortunately, fluorescent watch dials are no longer made of this material, but as a historical note, in the past, watch dials were fluorescent due to radium paint. There was a sad chapter in American history where there were watch painters that used to be paid by the piece. They were called the radium girls because what they would do is they would use camel hair toothbrush, sorry, paintbrush to paint the watch dials. And in order to keep the tip of the brush sharp, they would dip the paintbrush on their tongue. And so, one after another, after another of these workers eventually were discovered to have horrific radiation-related injury, morbidity, and mortality. Again, fortunately, we don't use radium as fluorescent material anymore. That's a historical note. Approximately three quarters of a million interventional endoscopy procedures are performed annually, many of which typically require some degree of fluoroscopy usage. But despite that, as you can see, in a survey by Dr. Amrita Sethi in 2019, a survey of nearly 160 interventional gastroenterologists across the country, the majority of which had substantial ERCP experience, over half of those individuals admitted they never received formal fluoroscopy training. And I will, as I mentioned, readily admit, I am one of those individuals that never received formal fluoroscopy training even during advanced fellowship. Lest you think that this is an American problem, it absolutely is not because in the UK, a similar type of study was conducted with essentially similar results. A quarter of the survey respondents admitted to not wearing thyroid shields on a regular basis, and less than half of respondents admitted that they did not routinely wear leaded glasses or eye shields during ERCP. And so part of the problem, at least here in the United States, is that there is no uniform licensure requirements. Every single state is allowed to put forth their own licensure requirements for the use of fluoroscopy. In my home state, for example, we do have a very rigorous non-radiologist physician fluoroscopy license requirement, Thompson Chrometric Exam Center is the whole nine yards. Conversely, these states have no licensure requirements at all for any x-ray equipment operators. And so you can see what the problem is when there is no uniform curriculum, depending on the time and the venue of, for example, advanced endoscopy training, one may not be exposed to the key concepts of radiation safety at all. Another problem that we noticed when thinking about the issue is that there is no federally mandated standardized controls. And so unlike, for example, an automobile where the brake is always to the left of the gas, for example, every manufacturer is allowed to create their own set of controls. And here is a representative image in our review of four separate machines in four separate locations. And every single one, as you can see, has its own sort of icon graphics, button positions, things like that. And this is especially important, for example, for those of us who may need to travel to different venues without throughout the hospital camps, for example, depending on where OR is available and seizures available. And depending on the age of the equipment, you may have widely disparate controls. And so that makes radiation safety challenging, a challenging task. But again, to tie everything together, I just wanna put this into perspective for the audience members. X-ray is part of the electromagnetic spectrum. As you can see, it spans widely from low energy waves, such as AM band to medium energy, such as, for example, microwaves and even the visible spectrum to super high energy, such as medical radiation and even nuclear power plant type of radiation. And so again, just to sort of, not to reiterate too much, but electromagnetic spectrum, sorry, radiation is part of daily living because it is part of our electromagnetic spectrum. So I figured this cartoon would be hopefully instrumental in helping the audience understand how a basic, for example, C-arm works in a typical fluoroscopy unit. And this is an example of an analog fluoroscopy unit. Next. So typically electricity comes from the power lines and it's in the form of alternating current. And when it comes into the radiation, sorry, the fluoroscopy unit, it gets upregulated to anywhere between 25 to 150 kilovolt peak. Next. This energy is subsequently delivered to the X-ray tube. Next. Where it actually sets off a stream of electrons targeted at a, for example, tungsten target. Next. The tungsten subsequently stops the electrons and it results in, next, X-ray release. Next. The energy is directed to the body part of interest. And as you can imagine, different body parts have varying degrees of absorption of X-rays. And therefore that generates contrast. And subsequently that is what produces an image. And eventually the X-ray is captured by the image intensifier, which helps brighten the image. And then eventually it gets transmitted to a camera where it is saved for archival purposes. Now, conversely, the anatomy of a digital fluoroscopy unit drum roll, please. Next. The image intensifier is switched out for a flat panel detector. That's it. I know, should have had a V8 moment, but, and this is very important because people intuitively may think that digital fluoroscopy is inherently safer than analog fluoroscopy. And I would challenge that it's not necessarily so. Because if an operator is not aware of how radiation is generated and delivered and scattered throughout the room, it can easily, you can easily imagine a situation where one may be tempted to take multiple images. And in many fluoroscopy setups, for example, that prompts the machine to send out a little bit burst of fluoroscopy in order for you to capture the image. Similarly, a natural phenomenon of X-ray imagery is that by overexposing an object, the image quality tends to get better. And so that's the opposite of what we want, except, again, if nobody ever told you, how would anyone expect you to know that? And that's the purpose of this slide is really just to demystify what a digital fluoroscopy unit is, but also to drive home the point that it's not automatically inherently safer. Another part of the challenge in terms of discussion of radiation safety is the fact that different individuals of interest are measured through different metrics. And as if that weren't confusing enough, there are different units of measurement when we're talking about, for example, in the United States versus the rest of the world where there's a metrics, the metric system. So for example, for the patient, as far as the patient is concerned, I mean, it makes perfect sense, but the source of radiation is from the X-ray beam. And there are different outcomes of interest and measurement metrics, but, and this may be intuitively makes sense for a lot of the audience members, but it may not, the primary source of radiation for the physicians, nurses, and techs in the room is actually from the patient through scatter. And as a result, there are different outcomes of interest. Again, the concept of radiation safety, particularly for the nurses and staff is that it absolutely is a cumulative lifetime exposure. And so this, if you remember nothing else, this is one of the most important slides in terms of how to protect yourself and your staff in the ERCP lab. And so why is this important? Obviously this is important, but it bears repeating why it's so important because, next, we're talking about the potential of adverse DNA effects as a result of radiation exposure. And so there are two basic principles through which radiation can cause potential DNA damage. And the first, it's kind of backwards here, but to match the cartoon, the first is the concept of indirect action, where, and this is a phenomenon where when X-ray is absorbed and electrons are released, that targets, for example, intracellular water, which may induce a hydroxy radical formation, which then in turn can hit the DNA in question. A real world example of this would be, for example, a ricochet car accident where a car and car accident and the affected car receives so much energy that it ricochets and hits another car, an innocent bystander. Contrast that with direct action, where basically it's a situation where X-ray absorption results in electron release, which the electron itself directly targets the DNA. And that's, of course, just a car and car accident in the real world. Now, depending on many factors, if there is sufficient radiation exposure to a particular cell or DNA, that may potentially induce apoptosis and pre-programmed cell death. However, the concern is not actually in those situations, but rather in the sublethal radiation doses, because if ionizing radiation can induce DNA breaks, two simultaneous breaks, the DNA tries to repair itself by rejoining the sticky ends. But as you can see in this cartoon graphic, there can absolutely be a fragment, a segment of DNA that is lost forever because there is no more replication possible because there's no centromere at the lost segment of DNA. And the concern always is, well, what if that segment just so happens to be very unlucky and it happened to be a tumor suppressor gene? And so this herein is the cartoon representation of why it is so important to stick to the principles of Lara, which is as low as reasonably achievable. Similarly, it's important to briefly just discuss the radiosensitivity of various tissues. As you can see here, the weighting factor of certain tissues are much, much higher, for example, breast, colon, lung, stomach. The weighting factor is 0.12 as compared to, for example, skin surface and bone. And this matters because in the real world application, it's important to note that it's crucial for, for example, interventional endoscopists to get form-fitted lead and not have excessively large arm holes because in those situations, you will have zero protection where the arm hole is. And if you spend a lot of time performing, for example, supine ERCPs, guess what? You are no longer facing the source. You are actually parallel to the source and you have very little protection on that side. Next slide. This was an interesting study. This was actually conducted in the UK of 83 interventional, sorry, sorry. They selected a cohort of 10 interventional radiologists in the UK and there was an average dose of approximately 83 procedures. And what's interesting to note is that at least, even though we drive on opposite sides of the road, apparently for interventional radiology, we perform them the exact same way. And so in the UK, the left side of the body happens to be the closest to the source, the patient, I should say, followed by the thyroid, followed by the head, followed by the right side of the body. Now, this may be very nuanced and subtle. You'll see this in a few slides, but this assumes that the source of radiation to the patient is under the table, which is known as an under couch system. Again, this is gonna be very important in a few slides. And so there are two concepts of a radiation, potential radiation injury, and those can be broken down into something called deterministic versus stochastic effects. So deterministic effects, as I mentioned briefly, is when there's a certain threshold of radiation exposure to that particular cell, above which that is much more likely to result in a cell death. So for example, a sunburn is a perfect example of cosmic radiation, actually, resulting in a deterministic effect. A stochastic effect, meanwhile, is due to the so-called sublethal radiation exposure. And as you can see, there is no so-called safe threshold below which the effects cannot happen. And so a real world example of this would be, for example, when one plays a slot machine. The likelihood of, well, I guess you wouldn't be winning, you'd be losing, but just bear with me. The likelihood of getting something from the slot machine may increase if you continuously play, but theoretically, you can absolutely get something, so to speak, from the slot machine, even with one pull. Yet again, it highlights the importance of ALARA, or as low as reasonably achievable. And again, this is a summary of the latest recommendations in terms of annual occupational dose limits. And it's important to note that there was a recent update to the NCRP, National Council of Radiation Protection, to align it with international standards. And so as you can see, for those that have been in practice for a bit, the recommendations now for lens of eye has actually been decreased to 50 millisieverts per year. And I mentioned this a few slides ago. This is also another critical slide for you to remember. So the source of the highest side of scatter is always next on the side of the X-ray source. And many of us may take this for granted. For example, in my local practice, the machine is an so-called under couch system. And so there's sufficient shielding in the underneath the table. However, there are some practices which still utilize the over couch system. And so I'm sorry to say for any of those in the audience that have an over couch system, this image is reversed. So two to three X dose is coming directly at your face. And this is very important because again, depending on your local practice, if you end up utilizing other service line equipment, for example, some urology C arms are intentionally over couched because when they do lithotripsy, that is absolutely essential information to be aware of because that absolutely impacts the amount of scatter that you get exposed to. So now we transition to special populations. Next. Pediatric patients. We'll start with that. Pediatric patients are in general, three to five times more radio sensitive than adults. And that's essential because again, radiation exposure is cumulative over a lifetime. And so what population studies have observed is, for example, there may be even some gender differences as well. For females, young girls, for example, there may be one excess radiation induced cancer per approximately 300, 390 CT scans. For boys, we believe that the risk is about one in every 600 to 760 CT scans. But as you can see on the table on the right, the risk continues to decline based on advancing age. And so this again speaks to the concept of as low as reasonably achievable, because again, yet again, radiation exposure is cumulative over one's lifetime. And so for every 100 millisieverts of exposure, for example, there is an estimated approximately 1% risk of increased risk of excess risk of cancer and a half a percent increased risk of fatal cancer is the latest scientific estimates. Pregnant patients. Many of us who do this line of work for a living has certainly encountered this population. And it's important because new gallstones are diagnosed in approximately seven, anywhere between seven to 8% of pregnancies and about 1%, give or take, pregnant patients with gallstones may develop symptomatic biliary disease. And so you absolutely can encounter this special patient population in your practice. And so the reason why I bring this up is again, the concept of deterministic versus stochastic risks, for example, not only to the mom, but really to the fetus, developing fetus. But again, I will say very clearly yet again, that the goal of tonight's talk is really to educate. It is not to terrify. So we'll definitely go over that in the next one to two slides. Now, on the one hand, as you can see this table from the CDC estimates that if an individual is exposed to certain varying degrees of acute radiation exposure, there is a potential increase of harm to the fetus, depending on the week of gestation. Now, having said all of that, I will make it very clear, real world translation, an average ERCP at most, typically for the reasons why we would even remotely consider ERCP in the pregnant patient population under most circumstances, is anywhere between two to six millisieverts. And so therefore in plain English, what this table is representing is, you need to perform eight to 25 ERCPs on a pregnant patient before you potentially are at risk of increasing risk of observable adverse fetal outcomes. And so that's important because again, the purpose of tonight's talk is to educate and inform. So yes, there's a risk, you know, absolutely there's a risk, but it's always important to put things into context. I mean, nobody in their right mind is going to offer up to 25 ERCP procedures on a pregnant patient. And so that hopefully will be a take-home point for the audience members to understand. Yes, there's a risk, but you know, let's put it into perspective. The risk is probably not that high. And so as a result, in fact, next slide, in 2001, the UN Scientific Commission on Effects of Atomic Radiation actually came out and said to their credit, radiation exposure, particularly medical radiation, I should say, has never been demonstrated convincingly to cause hereditary effects in human populations. I mean, we're not talking about natural disaster events, you know, like Hiroshima or Chernobyl or anything like that. We're talking about, you know, the target audience, you know, the medical professional community. And so that's also important to note as well to put everything into context. Obese patients is another patient population that you may encounter in your ERCP practice. You know, as we may all collectively know, there's increasing numbers of individuals in the United States and even worldwide with increasing rates of obesity. Two out of three Americans are either overweight or obese. And the reason why this is important specifically as it pertains to radiation safety is that with increasing BMI, there is increasing scatter from the patient because the machine, every single ferocity machine out there has this feature called automatic brightness control. And so when there is attenuation of the radiation beam, the machine does not know what the cause is per se, it just knows that it's receiving less photons and therefore it increases the milliampereage or the kilovolt peak to compensate, which of course naturally increases scatter. And so I wanted to give this study, sorry, this bar graph for your attention. This was actually a study in the cardiac cath literature. It was a study of over a thousand patients where interestingly 83 of the cohort was either overweight or obese. And what they found on multivariate logistic regression analysis was that with every unit of BMI increase, the physician dose increased by about 5%. And so as you can see, again, two people are affected when there is excess radiation utilization in these procedures. So not only the patient themselves, but also the physician from scatter. And now we come full circle. Really the whole crux of this talk is to give you practical tips on how to protect yourself, the staff, as well as the patient. And so the three pillars of radiation safety are the concepts of distance, time and shielding. Again, you may have come across this concept before, but it's important to explicitly give you practical examples of how to lower your exposure through effective distance, lower your fluoroscopy time and using proper shielding. There is a phenomenon in radiation physics known as the inverse square law, which states that radiation scatter actually drops as the inverse of the distance. And so for example, when you, as the physician, if possible, wherever possible, stand three times the distance away from the source, which in this case, in any RCP procedure would be the patient, that resulted up to a nine time reduction in scatter. And that is huge because like I said, you want to do whatever it takes to be cognizant of the amount of radiation that you deliver because indirectly it protects you and the staff in the long run. Now, interestingly enough, the same phenomenon is also observed for the patients themselves. When you move the patient away from the source and towards the image intensifier or the flat panel detector, you effectively achieve the same natural phenomenon. Time is of course, one of the most important factors for radiation exposure, not only to the patient, but also to the staff, physicians and staff. I should say better in the room. And a practical real world tip is, I would like to challenge many members of the audience to reach for the stars. It absolutely is possible for you to perform standard colodocal lithiasis cases in under one minute of fluorotype. In fact, consistently, the fellows that work with me, they know that I am, I always race for as close to net zero as possible. So we consistently are able to achieve for standard colodocal lithiasis cases as little as 0.1 minutes of fluorotype. There are of course, other pro tips that will be in the slide deck that will be distributed after this talk, but these are some of them here. And these are from the recent review that we just released in GIE. Interestingly enough, studies have shown that simply by documenting your fluoroscopy exposure, fluoroscopy usage in procedure reports, that may encourage the end user and the operator to hopefully figure out ways to lower their radiation fluoroscopy usage. And this is again, a natural phenomenon called the Hawthorne effect, in which individuals who are aware that they're being sort of observed and monitored tend to alter their performance accordingly. Similarly, along those lines, as far as time is concerned during an ERCP procedure itself, a practical tip is there is no need for continuous fluoroscopy. It is absolutely best practice to use pulse fluoroscopy where the machine is essentially, instead of 30 frames per second, it's going at 7.5 or 10 frames per second. And trust me, you can achieve your objectives effectively as a interventional endoscopist with low frame rate pulse fluoroscopy. And how low can you go? You can reduce your unnecessary exposure by up to 90% when you use low frame rate pulse fluoroscopy as compared to continuous fluoro. And so keeping track of exposure time, again, is important. Again, it's important to sort of not assume because for example, dosimeter usage may not be uniform nor consistent. And so dosimeters, typically most practitioners, physicians, for example, when they perform ERCPs wear one dosimeter at the collar level outside of the lead apron near the neck. And that is meant to sort of give you a sense of just the total aggregate scatter that you're exposed to in a given reading period. Now, in certain specific situations, you may actually want to wear two dosimeters. And if that is, for example, if the physician is pregnant at time of ERCP procedures, you may want to wear the second dosimeter inside the apron at the waist level. And that gives you a sense of how much penetrating radiation you are experiencing. Suffice it to say, it goes without saying, but I'll say it anyways. It just sounds redundant, but do not mix the two dosimeters up. You know, otherwise you will get a very frantic call from the radiation safety officer of your hospital saying, oh my goodness, doctor, so-and-so, you've been massively exposed. So it's crucial to have systems in place if you're gonna use two dosimeters, making it very clear that this is the collar dosimeter, this is the inside dosimeter under the apron. Shielding. Shielding is also critical to long-term safety, particularly to the physicians and nurses that are in the room. As I mentioned earlier, it is important to wear the appropriate type of shield. And the reason for that is in some practice settings, there may be, you know, off the shelf, off-rack type of lead aprons, I should say. And if the arm hole is excessively large, then there is little to no protection for that part of the body, for example, breast tissue. So it's important wherever possible to get custom fitted lead. Now, I put lead in quotes because lead, although it is the most effective agent, it is also the heaviest. And so now with advancing science, there are a lot of lead equivalents which help reduce the weight of the product. And so, for example, there are now lead aprons, with a half a millimeter lead equivalent, which blocks 93% or more radiation scatter. Similarly, if individuals potentially have low back pain issues, it may be advisable to consider a two-piece apron because in those situations, 50% of the weight is transferred to the hip, and that may help improve your biomechanics and body health in the long run. Structural shielding includes examples such as wall-mounted shields, mobile lead shields on wheels, for example, if an observer needs to be in the room, lead curtain around the image intensifier or flat panel detector. Now, interestingly, I put this here, the concept of collimation is also important. And this is why I'm glad that all of you are here tonight, because there is a feature on most modern fluoroscopy equipment which allows you to restrict the field of view with copper plates. What that does is it restricts the cone of X-ray beams to the identified target of interest, and that absolutely helps reduce unnecessary scatter, and in certain situations, may actually help improve image quality as well. So it's a win-win. Other tips. There is a concept, particularly those practitioners in mobile fluoroscopy areas, called the gantry angle. And in plain English, a gantry angle is when the C-arm is perfectly perpendicular versus when it's rotated on its C-arm axis. The point of that is to sort of remind the target audience that it's important to keep the incident beam perpendicular to the patient if possible, because if you imagine, patients are not perfectly circular. They are varying shapes of oval. And so the more tangential of an entry angle of the radiation beam, the more distance the radiation beam needs to traverse, and as a result, there's a higher likelihood of scatter. So again, wherever possible, try to keep the gantry angle of the X-ray source perpendicular to the patient. Magnification is also another pro tip. Again, wherever possible, try not to rely exclusively or heavily on magnification to achieve your objectives, because each level of magnification, depending on the machine, can increase the dose of radiation delivered up to 4X. And so one pro tip, for example, in our local practice, wherever possible, I try to start with a standard 035 wire, because that is readily visible under the most zoomed out view. And so that achieves, obviously, radiation savings in the long run. Now, the other pro tip that I think is worth mentioning is there is a recent update in terms of practice, and this is important to recognize and highlight, and in fact, that's what we're doing right now. The National Council of Radiation Protection now, within the past year, has now advised against pelvic shielding, particularly for patients of childbearing age or even pregnant patients. And the reason for that is if the pelvic shield is improperly placed and if it happens to be within the field of view of the radiation beam, it may inadvertently activate the automatic brightness control, for example, which increases the killable peak, which is obviously bad. Or similarly, again, if the pelvic shield is not properly placed, it may actually increase the likelihood of internal scatter. And so I know this is probably news to at least some of the audience members, but I figured we'd talk about this. This is the latest advances in radiation safety, and we wanted to share that with you tonight. And so in summary, I think it's important to break the concepts of radiation safety down into basic do's and don'ts. And so the top five do's and don'ts, I think, of radiation safety is, again, I know it seems self-evident, but we never want to assume, is the procedure absolutely necessary? Are there radiation-free alternatives such as EUS or MRCP? The concept of ALAR is crucial. Again, radiation exposure is cumulative over one's lifetime. Simply coming to this talk, I think I'm very flattered and honored that each one of you has taken time out from their busy schedules to attend this talk because it helps put the concepts of radiation safety first and foremost in your mind. Understanding the various metrics of radiation dose measurement, I think is a do. And again, the core principles, the three pillars of radiation safety are the concepts of shielding time and distance. Again, it sort of almost goes without saying, but I'm going to say it anyways, don't perform ERCP for marginal indication because it's a lose-lose for everybody. We're not even talking about the procedural risk. We're simply just talking about the radiation exposure aspect. If at all possible, try not to undertake unnecessary magnification because, again, there's up to a 4X dose increase with every level of magnification. You should, sorry, I know this is a double negative, but you should not, not use collimation. So basically you should use collimation. Again, it helps improve the image quality under many circumstances and similarly helps reduce unnecessary scatter. You should not, okay, sorry, that's, I got to change that next time, sorry. You should not use continuous fluoro. So basically, conversely, you should use pulse fluoro because pulse fluoro, you are able to achieve your clinical objectives and substantially reduce unnecessary radiation exposure. The last don't is I would challenge every single member of the audience to reach for the stars and go for as low as possible. There is no reason to hit the five-minute alarm bell for standard ERCP, for standard CBD stone cases. It absolutely is doable. And I would challenge every single member of the audience to aim for that aspirational goal. And with that, hopefully we have some time for questions. Next slide. I want to thank you all for coming. Like I said, we recognize that everybody is super busy. And so we want to thank each and every one of you for taking time out of your busy schedules to come to this webinar tonight. Thank you. Thank you, Dr. Kwok. That was really an amazing presentation. Really wonderful. And we want to point out to folks, if you didn't see the message in the chat, you can immediately download a PDF of the paper Dr. Kwok led that was developed under the auspices of the ASGE Quality Assurance and Endoscopy Committee. It's also on the ASG website in the guidelines section. You just scroll down to the quality section there. And we are ready to take your questions. So you can submit them, any questions or comments you have via the Q&A box. Please be sure to use the Q&A box and not the chat box to submit questions or comments. That's just going to keep us organized. So could I just ask you while we're waiting for questions to come in, Dr. Kwok, you had talked about pelvic shielding. And what I'm hearing you say is since the publication of this document, there has been an update. Could you just review that again? Was that public shielding for women? Yeah, absolutely. Thank you, Eden, for that question. So the answer is yes. I mean, and this is absolutely, it's a very dramatic improvement slash change in mindset. Again, back in the, you know, origins of fluoroscopy usage, it was felt initially that, you know, it would make sense that, you know, you shield radiosensitive parts of the organ, of the body, radiosensitive organs of the body. But what they've noticed over the years is that, so number one, actually, there may be updates coming in terms of true radio sensitivity, the waiting factor. I didn't even get to that. But number two, again, they've seen time and time again, if the shielding is not appropriately employed, and if it happens to be in the field of view of the radiation beam, that inadvertently makes the situation much worse because the machine doesn't know any better. It doesn't know if there's an obstruction due to a pelvic shield or obesity or whatever. All it knows is that it's not getting enough of the signal throughput. And as a result, it increases the kilovolt peak or milliamp bridge. Okay, so we have some questions coming in. Our first question is, how does image quality get affected in low intermittent dose or decreasing voltage? Also, is there any standard of how many, how image quality is measured in relation to fluoroscopy parameters? And they thank you for this presentation. Oh, you're very welcome. So in the radiation physics world, there are semi-quantitative methods of measuring image quality. There are actual standardized devices, which allows the radiation safety officer, for example, to measure line pairs when you shoot images. But I will say in practical real world scenarios, for example, in our local machine, I'm not gonna mention the brand name, but in our local machine, a lot of the parameters are actually pretty set. And, but however, one of the factors that we can adjust is the frame rate. And so 7.5 frames is the lowest. And then of course, I mean, that has its own iconic iconography versus a continuous floral, which is a continuous line. Again, there's no difference, at least in our local machine. It's important to talk with your local radiation safety officer and see if that impacts, negatively impacts what you're trying to achieve. And I will say this, having said essentially the direct opposite earlier, I'm not saying never use magnification, for example. What I am saying is just be mindful of how magnification works. Actually, you can read more about this in the review, but the way magnification works is it actually decreases the amount of photons that reach the image intensifier. And so as a result, the machine automatic brightness control kicks in and therefore the voltage goes up. That's why it can be problematic when a physician, for example, relies heavily on magnification, for example, for every single case. And our next question is, is there an average MSV exposure to providers per standard ERCP? Is this data available? The short answer is yes. The long answer is like many topics in science, the values have changed over time, generally for the better, based on increasing awareness and increasing sophistication of the machines. So I'll give you a perfect example. There is one vendor now, again, I'm not gonna name brand names or anything like that, that has started to employ artificial intelligence to help collimate the field of interest. And that of course naturally will automatically show dividends. In fact, Dr. Ji Yong Bang and associates actually looked at this recently within the past one to two years. And naturally it goes without saying that when you collimate better, your scatter and exposure drops. And so again, for the providers, so I will say it like this. Average ERCP is anywhere between two to six millisieverts to the patient, as you heard earlier in the talk. And so when you wear a 0.5 millimeter lead equivalent, that attenuates up to 93% of that. So, sorry, I can't do math on the fly, but it's pretty low. Okay, some more questions coming in. When you start at a new job or a new hospital, how do you go about getting your own properly fitted lead and eyewear and where do you recommend getting it? Are certain types better than others? That is an excellent question. I'm going to answer thusly, the person that cares about you the most is you. So it is absolutely incumbent upon you to insist politely that you should have custom fitted lead. And you can point to the white paper, the guidance document as a reason why. And so for many reasons, right? When you have custom fitted lead, number one, if that's what you do for a living, right? It is absolutely essential. It's almost like professional baseball players, right? They have their own bats and things like that. I mean, there should be no difference for professional ERCP physicians. As far as specific types, there's all different types out there. Again, our goal is to be platform agnostic. So we can't recommend one type versus another. I will say that in many, if not all practice environments where there's a radiation safety officer, they will have likely vetted all locally acceptable vendors in terms of performance characteristics. So they can't, they're not just gonna allow a lead to say, lead a vendor to say it's 100% attenuation and we'll prove it, right? So it is checked for safety. As far as the specific brand or vendor, I don't think there's a significant difference among the multiple various brands out there. Wonderful. And so this person has three questions for you and that'll probably take us up to the top of the hour. So first they say, thank you for a great talk, super important topic, just a few questions. So the first question is, what pulse per second rate do you use for standard common bile duct stone cases? So for me personally, I use the lowest possible setting. And from my discussions with our radiation safety officer locally, it ends up being a 7.5 frames per second. Now, for some machines, you may not be able to achieve that. It may be that at your local institution, it may be 10 frames per second, but bottom line is you do not need Cine 30 frames per second. That's the take-home point. The lowest possible that allows you to achieve your objectives is probably likely gonna be 7.5 or 10. Next question. What are your thoughts on lead caps, lead extremity protection? I see the cardiologists in the cath lab use them regularly. A nuanced answer for sure. I will say it thusly. Any shielding may provide a dividends but having said that, as you may have also heard, the single most important determinant of radiation exposure is time. So you can achieve a lot of the same results by just not stepping on the floral pedal. Okay. When appropriate, of course, when appropriate, of course. And the last question, I think you touched on it with the prior query, but let's go ahead and do it again because I think it's important. How have you been successful in discussing these issues with the hospital to make sure the appropriate lead safety equipment, shields, under couch machines are available for use? Absolutely. And that is actually a very important discussion. I would say this. I'm happy to discuss further offline the audience members' concerns, but generally speaking, most health systems and places where fluoroscopy is used, there has to be a radiation safety officer. Now, if the question, for example, happens to be, well, how do I switch from an over couch to an under couch system? That's a much more nuanced sort of approach because ultimately we are, many of us, I suspect, are probably employees of medium to large size organizations. Now, if there's an opportunity for you to share guidance documents and help guide the discussion, absolutely. I think that's gonna pay dividends. But some of the things that you can do, for example, starting tomorrow, is to be cognizant of the amount of time that you step on the floral pedal. Again, single most important determinant is the time on the pedal. But again, it's a much more nuanced answer. And I understand and appreciate every single practice setting is a little bit different, but that's probably what I would recommend starting tomorrow morning, for example, is just be cognizant of the amount of time that you step on the floral pedal. Are you aware, Dr. Kwok, of any resources out there that people could post in their units? I mean, I almost feel like some of your slides, I just wanna print them off and laminate them and hand them out. So are you aware of any resources out there that folks might be able to access? And maybe they, like you said, start local, start right within your room. Yep, yep, absolutely. And I'm really glad you brought that up, actually. So the answer is yes. The International Atomic Energy Agency has a PDF, which we are happy to circulate to the audience members a little bit later. They do have top 10 tips on radiation safety. It's in a PDF format. And so we're happy to share with the audience members. And you can simply just print that out and post it in your lab, for example, starting tomorrow. So the answer is a resounding yes. And we're gonna sneak in one final one. We're at the top of the hour, but is there any data to protect the head, I guess? Is there any data on protecting your head? There are some studies out there. In fact, there was a recent randomized control trial, sham versus actual protection that came out in GIE, I believe two and a half or three years ago now. And it makes perfect sense. I mean, it's a very logical conclusion. When you wear lead equivalent shielding products, it naturally, you show a substantial reduction in scatter exposure to that part of the body. Now, again, however, whether that is a uniform recommendation, it depends, right? It depends on many, many factors. Again, I will challenge the audience to reach for the stars or reach for the bottom of the lake. I don't know if that's a terrible analogy, but to go as low as you possibly can in terms of daily usage of radiation, I'm sorry, fluoroscopy usage. Many of us do things through habit. And so if you start, for example, start documenting the amount of radiation you use per case, you may even notice that over time, that time number drops. Yeah. Well, thank you, Dr. Kwok. This was a wonderful presentation peppered with so many wonderful analogies, I must say. You added a lot of character to the presentation on such a valuable topic. We have come to the close of the presentation. As a reminder, a recording of this session will populate your GI LEAP account when it's available, and we expect that to be available next week. We will send out an email to you all to let you know that it is available, and we'll include a link to the reference, the resource guide that Dr. Kwok spoke to. This concludes the presentation on radiation and fluoroscopy safety and GI endoscopy. We hope this information is useful to you and your practice. Thanks, Dr. Kwok.

Dr. Carl Kwok

interventional endoscopist

radiation safety

fluoroscopy safety

GI endoscopy

radiation protection

occupational dose standards

ALARA

radiation exposure

radiation safety training