What You Can’t See CAN Hurt You!

I frequently visit various cardiac catheterization laboratories both in the US and abroad and watch live cases at various interventional meetings. I find such experiences invaluable for “opening the mind” to new, different, and often better ways to do what we do every day. However, there is one aspect of the catheterization procedures that I often find discomforting: radiation safety practices vary widely and are often ignored. I recently observed an expert interventionalist skillfully complete two extremely challenging peripheral interventions. In both cases, his hands were in the middle of the radiation beam for several minutes (Figure 1)! The response to my pleas about this was: “I did not like it, but I had to do it.”

Dr Geoffrey Hartzler, one of the pioneers of interventional cardiology, died on March 10, 2012 following a battle with cancer at the age of 65. Did his exposure to radiation play a role in his death? No one can give a definitive answer, but the answer is likely yes.

Working in the cardiac cath lab carries 3 main hazards: (1) radiation exposure; (2) needle stick injuries/accidental exposure to blood; and (3) orthopedic injury from standing for long periods of time wearing heavy lead aprons. We all learn in medical school that there is no “safe” needle stick or “safe” exposure to radiation; however, unlike the immediate palpable nature of an inadvertent needle stick, radiation exposure is more insidious, making us complacent about guarding against its untoward consequences. Significant radiation exposure can lead to skin injury, which may not be evident until weeks or months later, and is commonly misdiagnosed. Radiation can predispose to cancer, cataracts, or possibly adversely affect reproductive capacity. Earlier this year, a series of 4 interventional cardiologists who developed left-sided (the side that is more exposed to radiation) brain tumors was published.

Should x-ray machines in the cath lab come with graphic photos showing hand cancer or lymphoma or amputation, similar to those that the FDA is trying to mandate for cigarette packets? What is needed for interventionalists to take the risks of radiation seriously?

Although radiation safety is mandatory, it is often yet another “boring” component of the training required to keep our jobs. We read a few pages, answer some questions, usually on some esoteric aspects of radiation physics, and life goes on… but at what cost?

My personal journey with radiation exposure truly began when we started a chronic total occlusion (CTO) intervention program about 6 years ago. This was the first time I started to intently look at the radiation exposure numbers appearing in the screen. This is when the term “air kerma” — AK — started to make sense and became the main number to look at, rather than the dose area product or DAP. This is when the actual radiation exposure cutoffs and risks started to solidify: 5 Gray (Gy) is when the risk goes up, 10 Gy means that the patient is likely going to get at least skin erythema, and 15 Gy is the number never to be reached because it could create a non-healing ulcer in the back of the patient (and would also require reporting to the regulatory authorities). Imaging using less radiation is critical in CTO interventions, because it means that more time is available for crossing and ultimately succeeding. I was pleasantly surprised to see that what started as a CTO intervention check item, subsequently “spilled over” to all cardiac catheterization procedures I perform.

How can interventionalists reduce radiation exposure? The simplest first step is to not step on the fluoroscopy pedal when not looking at the screen. Although this appears self-evident, I remain amazed at how often this simple principle is ignored! Another obvious second step is to not insert our hands in the radiation field. Of course there are exceptions — occasionally in an arresting patient undergoing emergency PCI the hands of the person performing cardiac compressions may get in the beam — but this should be the exception, rather than the rule.

Radiation exposure can also be reduced by carefully positioning the image intensifier as close to the patient as possible, frequently changing the image intensifier angulation to minimize the skin dose at each entry point, using less angulation with low-dose fluoroscopy, and carefully positioning the radiation shields. There is also an increasing array of radiation dose reduction technologies, such as devices that provide real-time auditory alerts in response to radiation dose and additional disposable shields, for placement into the sterile field.

In my opinion, the key to reducing radiation dose is the creation of appropriate “radiation reducing” habits, which should start during fellowship. I strongly believe that we should be neurotic about radiation.  Once the appropriate routines are engrained, they become second nature and one performs them automatically.

Radiation reduction is a win-win situation for both the patient and the operator. Investing the time and effort required to develop sound radiation reducing habits can provide high dividends, such as saving our lives and the lives of our patients from potentially preventable radiation-induced illnesses!

Roentgen died from radiation-induced cancer because he did not know the devastating consequences of x-ray exposure. We do not have the same excuse: we should never forget that being unable to see an immediate effect of radiation on our body or the patients’ bodies does not mean that we are safe!

Emmanouil S. Brilakis, MD, PhD is Director of the Cardiac Catheterization Laboratories at VA North Texas Healthcare System and an Associate Professor of Medicine at the University of Texas Southwestern Medical School. Vishal G. Patel, MD, is an interventional fellow at the University of Texas Southwestern Medical School. Email: esbrilakis@yahoo.com