<p id="p0010">Coronary angiography and intervention are inextricably linked to the use of radiation. One becomes best aware how much we need X-rays when our equipment fails during an interventional procedure. We are completely blind and helpless without X-rays.</p> <p id="p0015">While we need radiation, radiation is bad both for patients and medical staff. Early radiologists learned the harmful effects of radiation the hard way. Similarly, radiation injury to patients, while uncommon, is a clear and present danger of complex or repeated procedures.</p> <p id="p0020">In this issue of <em>Cardiovascular Revascularization Medicine</em>, Hasegawa et al. report a retrospective analysis of skin radiation dose in contemporary Japanese clinical practice. They found a strong association between body surface area (BSA), right coronary artery (RCA) percutaneous coronary intervention (PCI) and chronic total occlusion (CTO) procedures with excessive radiation doses.</p> <p id="p0025">When interpreting applicability of any research studies to one’s local practice, we need to stop for a moment and look where the study is coming from and what the patient population is. These are Japanese patients with an almost unheard-of body mass index (BMI) of 24. We hardly ever see such patients in the US. We have previously analyzed differences in global study populations and found large differences between prevalence of hypertension, diabetes, and basic height and weight. The BMI in this study by Hasegawa and colleagues is exactly in line with findings in our meta-analysis. In comparison, BMI in Europe was 27 and in the United States, 29.</p> <p id="p0030">It is important to recognize these population research differences. In the study by Hasegawa et al., large body habitus was strongly associated with increasing radiation doses, and as the authors point out, this is a component of radiation dose that is clearly not modifiable. What this directly means to the North American reader is that with our population being heavier than the Japanese, radiation doses will be higher across the board in our practice.</p> <p id="p0035">With the growing complexity of PCI in contemporary practice, CTO intervention is here to stay. The sobering finding is that CTO-PCI and radiation association have an odds ratio (OR) of almost 7 in the study by Hasegawa and colleagues. The current discussion in interventional cardiology revolves around increasing rates of CTO intervention due to availability of better tools and marked improvement in CTO techniques. We hardly ever discuss this “dark” (radiation) side of CTO-PCI. In a certain way, a major step in PCI safety occurred with the transition to radial access, when we learned that radial arterial access reduces bleeding complications from PCI. At this time, radiation reduction in CTO procedures seems to be at a very early stage. To truly make CTO a mainstream procedure, radiation doses will need to come down. While radiation protection for the operator is part of the solution, radiation delivered to the patient will require both a CTO technique and radiation reduction technology leap.</p> <p id="p0040">There have been multiple improvements in the way we deliver radiation and protect ourselves from radiation. Image noise reduction systems, real-time radiation monitoring with auditory feedback, various disposable radiation absorbing drapes, and “weightless” aprons have all helped reduce radiation dose over time. While we made significant progress in access-site bleeding reduction with radial arterial access, the radiation dose has, in fact, slightly increased with the transition to radial access. At the same time, fellowship training education about radiation appears to be a secondary priority for many training programs.</p> <p id="p0045">It is clear that we will need a technological leap in the cardiac catheterization laboratory to take our field to the next level of safety and performance. First of all, the way we interact with fluoroscopic equipment will need to change. Foot-pedal activation, combined with touchscreens and various mechanical buttons, is becoming rapidly outdated. How we interact with the equipment will have to evolve to a bidirectional communication. Fluoroscopic equipment will require us to become intelligent “partners” in the image acquisition process. With the field of artificial intelligence rapidly evolving, equipment will have to learn our behaviors and adapt to them as well as provide active and real-time intelligent feedback to reduce radiation dose .</p> <p id="p0050">Multimodality fusion imaging offers great possibilities to improve our diagnostic and therapeutic options, particularly in the rapidly growing structural cardiac intervention space. Traditional image interpretation associated with traditional image acquisition is similarly becoming obsolete. Integration of artificial intelligence in the cardiac catheterization imaging workflow will likely significantly help reduce radiation dose by eliminating unnecessary images and by providing us with more information from shorter and higher-quality cineangiographic acquisitions.</p> <p id="p0055">What remains to be determined is whether a human operator will need to be physically present in the vicinity of the source of radiation. The technology that exists today is clearly a step in the right direction, and robotic-assisted PCI has made enormous progress in only a few years. With the field of robotic surgery, our surgical colleagues have overtaken the technology currently in use in interventional cardiology. I recently made a short visit to the robotic transplant surgery suite to discuss a collaborative project with my surgical colleague. The most striking impression was how far behind the field of interventional cardiology was compared to the technological ability of surgeons to operate with the assistance of a “robot.”</p> <p id="p0060">Fast-forwarding to the robotic future where the physician does not wear lead and there is minimal or no radiation exposure for the healthcare worker, we still do need to solve the radiation dose the patient receives. This area is a prime target for major advances afforded by artificial intelligence and machine learning. Intelligent and interactive X-ray systems could provide optimal angulated views that may automatically adjust during the procedure to minimize skin dose to one area only. Real-time radiation dose feedback with better and more intuitive visualization of the delivered dose to the patient will allow us to tailor the procedure length and optimize operator conduct. Available prediction calculations of radiation dose for a planned procedure with continuous updates during the procedure could change physician radiation behavior. We currently perform preprocedural estimates for the risk of acute kidney injury or bleeding risk. Why not estimate the radiation dose?</p> <p id="p0065">And lastly, an often-overlooked area where we could make tremendous reduction in radiation dose is the contrast dye. The way we administer contrast dye has not changed since its advent. We inject the dye, and it gets washed away. This evanescent nature of the dye is extremely valuable, as it allows us to determine how brisk the coronary flow is or observe “no-reflow” phenomenon. But repeated injections hurt the kidneys and increase radiation. Various new developments such as dynamic “roadmapping” or combined with catheter tracking without the use of radiation may help eliminate much of the dye injected or radiation needed for CTO procedures. We need to develop new and innovative solutions to replace current contrast dye. This would protect both patients’ kidneys and reduce radiation dose to all involved parties.</p> <p id="p0070">The paper by Hasegawa et al. in this issue of <em>Cardiovascular Revascularization Medicine</em> is an excellent analysis of our contemporary practice of interventional cardiology. It clearly demonstrates that we have reached the limitations with our current technologies and that we need radical technological innovation to advance the field to the next, safer level. The ultimate goal is a zero-emission cardiac catheterization laboratory.</p>