My name is Tim Bateman. I'm a cardiologist in Kansas City. I'm speaking with Dr. Gary Heller today about the transition from SPECT to PET. So Dr. Heller, I've listened to your talks many times over the last few years as you have discussed the steps that a practice or a small hospital might go through in adopting PET technology for cardiac imaging. Now the phase three study for F18 florpyridaz has been finished and we're anticipating approval of this new PET tracer in the future. You want to talk a little bit about the steps that a practice might contemplate in making the transition from SPECT to the adoption of PET for florpyridaz? It's a very interesting challenge because florpyridaz is a new agent and we're not quite sure how it's going to fit into the clinical armamentarium. What I suspect will happen is that existing PET cameras that are somewhat underutilized for oncology will be a perfect place to initiate cardiac PET programs with florpyridaz. A lot of hospital now have cardiologists that are actually part of their faculty. And so you should be able to get access to those cameras. I think it's a really good way to start a PET program. So on the other hand, a practice that wants to begin a PET program I think needs to think about both the tracers that are available now, which is either ammonia or rubidium, and then add F18 florpyridaz. And so you have to think about the configuration of your settings, such as the rooms that are available, the camera systems, and how you're going to fit this into a program. So I think it will add a new dimension. And perhaps because you can do both exercise and pharmacologic, the number of patients you need to do an active PET program will actually be less. Right, right. So for an office-based practice, a fluorinated tracer actually has some distinct advantages, doesn't it? It does indeed, yeah. You know, the camera systems that are in use today have all been optimized for fluorinated tracers, FDG imaging for oncology, for example. And a tracer with a longer half-life has got some very practical advantages. Do you want to go over some of those? Well, longer half-life and also the annihilation event is much closer to the origin. And so we really anticipate that this agent will produce excellent images, which it does. And I think it's going to be easier than either ammonia or rubidium. So I think that's a real interesting advantage. And the trial itself included those sorts of cameras that are in the system right now, both dedicated PET and, in a sense, older PET-CT cameras, which will function very well with fluoroperidine. So I think you're correct. Right, yeah. The image quality was rated as excellent or good in the vast majority of studies in the phase two and the first phase three and the second phase three study. So that's important. And I've actually had the opportunity to look at these images, and they're gorgeous. There's no question about it. The long half-life also gives you the opportunity, if need be, for the first time with respect to PET perfusion imaging, to be able to reacquire the stress image in the case of poor quality images, patients moving, and so forth. That's pretty novel. No, I think it is. But there is a downside to that, too, and that is that right now the rubidium protocol can be completed in a very short period of time. I think with fluoroperidase, it's going to be longer. On the other hand, you will be able to reacquire data. However, we also have to figure out where blood flow is going to affect that as well. Right, sure. But on the other hand, this is the first new tracer that we've had in 35 years. I think you said earlier that this is the first new tracer, but my friend, I think you recall technetium sesamivi? Yeah. I think that was on your watch as well. It was. Late 1980s. Yes. Actually, it was interesting because sesamivi was a very important step forward from thallium, and yet the acceptance took years. And I think that perspective is going to hold true with fluoroperidase. On the other hand, within 10 years, a modality such as nuclear cardiology that was 100% thallium became 95% technetium. It'll be interesting to see what happens in the next few years. Right. Well, that's sort of the history, isn't it? These studies that need to be done for regulatory purposes to get approval of the agent, you know, after that, after the introduction of the product, there's lots and lots of research that goes on and protocol modifications and so forth. I think we can probably expect the next five years to be pretty fascinating as this new agent takes over. No, I think that's true. And that's a very important topic because the purpose of the phase three trials is to get this tracer into the marketplace. And so the protocols that were developed don't necessarily mean they will be translated to an individual laboratory. And I suspect, as with sesamibi, they will be shortened considerably and we'll figure it out. And the protocols will be, in a few years, much shorter than what we saw in the phase three trials. Right. So, if a practice was thinking today about transitioning from SPECT to PET, what you would advise a couple of years ago when we were only talking about options of rubidium or ammonia, and now we also have to talk about the potential of implementing fliropyridaz in the lab, what differences would a practice need to think about? Yeah, those are important considerations. And I think the issue is this. Five years ago, you were going to use rubidium or ammonia, and the lead shielding was different. You didn't need to have any protection for patients during the injection time, which we now have to think about. But my advice to somebody beginning to think about PET is prepare for F18. And that is, fliropyridaz, there are several other perfusion agents in the developmental stage. So, this is going to happen. And the other thing is that it also gives you the opportunity to use F18-FDG, which has enormous opportunities in sarcoid infection imaging. And so, this will actually expand programs that, in the previous time, were confined to rubidium only. So, this is an expansion of nuclear cardiology and our applications in many different disease states. Right. Now, you chair a PET committee within ASNIC. What do you think the steps are towards educating the community about F18 myocardial perfusion imaging? Yeah. No, that's a very, very important topic. And while these images are clearly very good, there's still a training process. And you need to understand this agent. I think the obligation of both the sponsors of the tracer, as well as the American Society of Nuclear Cardiology, is to provide the appropriate training. And those thought processes are ongoing right now within ASNIC and actually within the PET committee as well. Well, thank you, Dr. Heller. You have been instrumental in this whole development of the PET myocardial perfusion field. And I'm sure you'll be playing an active role as we understand the value of F18 flurbierdes.

Dr. Gary Heller

Dr. Tim Bateman

SPECT to PET transition

F18 florpyridaz

cardiac imaging