Hello, everyone. My name is Dennis Calnon. I'm a multimodality imager in Columbus, Ohio, and Director of Nuclear Imaging at OhioHealth Heart and Vascular Physicians at Riverside Methodist Hospital. I'm going to cover for the next 10 minutes, not-so-fast barriers to cardiac PET adoption. Recently, Dr. Amala and colleagues published in Journal of Nuclear Cardiology a little snapshot from the Medicare data about the volumes of testing for coronary artery disease assessment in the Medicare population. And what you can see, if you focus in on 2022, you can see a couple things. One is that SPECT imaging, SPECT MPI, is by far the most commonly performed procedure. But PET, myocardial perfusion imaging, is now second in terms of volume in the Medicare-aged population, higher volume than stress echo and much higher than coronary CTA or stress cardiac MRI. The other thing that's notable is that these are mostly read by cardiologists. In PET imaging, 86% of studies are read by cardiologists, just like SPECT and stress echo and stress MRI, which are predominantly done by cardiology. If you look even more closely at the volumes, though, you'll see that even though PET is now used more commonly in this patient population, the ratio of SPECT to PET studies is still greater than 6 to 1, so there's still a ways to go. And if you look at the number of PET readers, there's only less than 2,000 PET readers as of 2022, and this is, you know, seven times less than SPECT readers. So cardiac PET is making progress in terms of being more widely adopted, but it's just not quite there yet compared to SPECT. Another study was published in Jack Imaging this year by Dr. Amalagroup, again with Dr. Syed, and they looked at the volume of cardiac PET centers around the United States. You can see on the right, this map shows in red the areas that have cardiac PET centers, and you can see in the color coding of the states that only Texas and to lesser extent California and Florida have a high number of cardiac PET centers, but many areas of the country really do not have cardiac PET centers. On the left of this slide is a map of the hospitals in the United States from back from 12 years ago. In 2012, there are probably more hospitals now, and you can see that there are many, many areas of the country that have hospitals and yet do not have cardiac PET centers. In the study by Dr. Syed and colleagues, they've noted that 44.2 million of the U.S. population or 13.2% of the U.S. population live more than 100 kilometers from the nearest cardiac PET center and that there are no cardiac PET centers at all in several United States states, Montana, Rhode Island, West Virginia, Wyoming, and the territory of Puerto Rico. And also, a market study from back in 2022 showed that among large hospitals defined as greater than 400 bed hospitals, only 26% of them offered cardiac PET, and only 8% of PET scans performed in the United States were cardiac PET studies, so making progress but a long way to go. So what are some of the reasons why cardiac PET is still slowly becoming more widely available? One of them is that many cardiologists lack formal training in cardiac PET during their cardiology fellowship. It's becoming more available in some large centers who offer advanced imaging fellowships, but it's not widely available to the majority of cardiology fellows in training. Secondly, is that making the move from SPECT imaging to cardiac PET imaging also involves, in many cases, transitioning from nuclear imaging alone to hybrid imaging with PET-CT. Most modern PET cameras these days are PET-CT hybrid imaging systems, and even though cardiologists are often comfortable reading cardiac CTA studies, in many places, including at our hospital, the non-cardiac structures on cardiac CTA studies are overread by radiology for important incidental findings, and many cardiologists are not comfortable being responsible for all of the non-cardiac CT findings. Similarly, nuclear technologists in many states, including in my state of Ohio, are not permitted to perform calcium scoring, which is considered a diagnostic CT scan, which is another thing that makes people hesitant to jump in. Another reason is because exercise PET imaging is not feasible with rubidium due to the short half-life, and it's challenging with ammonia as well, and so people who are thinking about switching from offering SPECT to PET are worried about giving up the ability to assess perfusion during exercise. Another very big reason is that there's a lack of awareness among hospital and heart service line administrators regarding the benefits of cardiac PET, and what I really believe is that there is a strong need for a local physician champion to push for cardiac PET to be incorporated at their hospital or their large practice, and to explain the benefits and make a case for it. And without a physician champion, it's very difficult to get a cardiac PET program started. And finally, using a shared PET camera, which is available at many hospitals who perform PET for oncology or other applications, it's difficult to justify using it on a part-time basis for cardiac imaging because you still need to pay for the strontium generator if you use rubidium as your tracer or an on-site cyclotron for ammonia, and the large cost of these, it makes it challenging to use cardiac PET on a part-time basis. So if you look more closely at some of the barriers, as we mentioned, cost is by far the biggest barrier. This is information from a 2023 American Society of Nuclear Cardiology member survey, and one of the big reasons for not transitioning to cardiac PET was concerns about the cost. There are also some concerns about the additional training required and space requirements. The hesitancy to embrace hybrid imaging is also something that we should not underestimate. When asked by cardiologists who interprets the incidental findings on CT images, most of the time that's not done by cardiology and done by radiology for cardiac CT reading. And when asked, does your technologist require additional training to perform calcium scoring, the majority of respondents in the survey said yes, and that's true at our site as well to perform calcium scoring. Until very recently, the only two tracers that were available were N13 ammonia and rubidium-82. Ammonia requires an on-site cyclotron, and rubidium requires an on-site strontium generator. So the upfront cost for these is significantly higher. These were the only two that were FDA approved. So very recently, as of this recording, recently floperidaz has now been approved by the FDA. It's still not widely commercially available. I'm not aware of the price yet, but this is a big deal for the field of cardiac PET, which we'll talk about. And the main reason is because the F18 label for the floperidaz offers a longer half-life of 110 minutes. This means two things that are very important. One is that this allows for unit dose delivery from a local radiopharmacy, and of course, assuming that the cost will be acceptable for the floperidaz dose, this will make a dramatic improvement in terms of the financial viability of starting a cardiac PET program. The other is that the long half-life of 110 minutes allows you to perform exercise stress PET with floperidaz. So these are going to be two big things that make a big difference. So in summary, thinking about trying to increase patient access to cardiac PET, most importantly is to alleviate the financial obstacles. Floperidaz will help in this regard very significantly by allowing many laboratories who have access to a PET camera but don't have a cardiac PET program to begin using floperidaz for their cardiac PET to get started. Secondly, is to enhance training opportunities for cardiology fellows and cardiologists who are in practice who perform SPECT imaging but are not familiar with cardiac PET. This type of education is available through ASNIC, who offers cardiac training with workshops and a PET curriculum. So these are certainly available, and I encourage people to take advantage of these. Training for nuclear technologists is important as well. We have many nuclear technologists around the country who are very familiar with SPECT imaging but not familiar with cardiac PET. There are also technologist workshops through ASNIC that are available, and I encourage your technologists to take advantage of these. Hybrid imaging education is also important for cardiologists who are not comfortable interpreting the non-cardiac structures for important incidental findings on the CT attenuation correction images. Hybrid imaging workshops are also offered by ASNIC, and I encourage you to do this. Creating new licensing pathways for nuclear technologists to be allowed to perform coronary calcium scoring will be important. CT attenuation correction images can be acquired by nuclear technologists without additional CT training, and this is what we do at our hospital, but even better would be to perform a formal calcium score or more quantitative assessment of calcification, which often requires nuclear technologists to get additional CT training. And finally, we need to educate hospital administrators, heart service line administrators, and referring physicians regarding the clinical value of cardiac PET. Programs such as this webinar that you're watching right now will be helpful, and I encourage you to share this information with your hospital administrators and heart service line administrators. So with that, I want to end by saying that I'm very optimistic about the future of cardiac PET, and I think that the availability, the FDA approval of floperidaz will make a very big impact in terms of the patient access to cardiac PET across the country and around the world. Thank you for watching.

cardiac PET imaging

barriers

FDA approval

training

floperidaz