Watching for Radiation Harm After Interventional Procedures

Christina Bennett

December 09, 2019

Interventional procedures can expose interventionalists and nearby staff to high doses of radiation, and this can lead to radiation-associated lens opacities, said Madan Rehani, PhD, director of Global Outreach for Radiation Protection at Massachusetts General Hospital in Boston.

These are different than the typical opacities seen in clinical practice, he explained, as they tend to develop in the posterior area of the lens while the more common lens opacities, such as those related to age, favor the anterior or nuclear area of the lens.

"Many times, the ophthalmologists will do the eye check and may not even look at the posterior subcapsular part because they are often used to looking at the anterior and nuclear part," Rehani told Medscape Medical News.

Studies have shown that interventionalists as well as support staff are at an increased risk for lens opacities. For instance, a 2010 study found that among 56 interventional cardiologists in Buenos Aires, Argentina, 29 (52%) had lens opacities whereas only 2 of the 22 healthy controls (9%) had lens opacities, translating to a 5.7 (95% confidence interval [CI], 1.5 - 22) relative risk of lens opacity for interventional cardiologists.

The study also showed that 5 of the 11 nurses (45%) who participated in interventional procedures had lens opacities, which translated to a relative risk of 5.0 (95% CI, 1.2 - 21) for nurses.

Similar findings were reported in 2012 and 2013 studies, both of which comprised interventional cardiologists and support staff from outside of the United States.

Evidence also suggests that lens opacities in which vision is not affected do worsen over time, eventually transitioning to cataracts. However, "we have no idea" whether this transition will take 1, 10, or 15 years, said Rehani.

The good news is that radiation-induced cataracts are "100% preventable" by using the appropriate protective tools during a procedure, such as lead glasses, he added.

Rehani gave one of three talks during a session titled "Making Patients and Staff Safer in Interventional Procedures" at the Radiological Society of North America (RSNA) 2019 Annual Meeting in Chicago.

Another concern that is less clear cut is whether interventionalists and staff have an increased risk of contracting cancer.

Cancer Risk Unclear

According to a 2017 large cohort study of 45,634 physicians who perform fluoroscopy-guided interventional procedures, the total deaths from cancer as well as other causes were not elevated for these physicians compared with psychiatrists. Given this study, Rehani said, interventionalists "should not have this fear" of having a higher risk of cancer.

However, Paula Novelli, MD,  interventional radiologist and associate professor of radiology at the University of Pittsburgh, was not entirely convinced. Novelli explained that a 2016 prospective cohort study of 90,957 radiologic technologists reported a more than twofold increase in brain cancer mortality (hazard ratio [HR], 2.55; 95% CI, 1.48 - 4.40) and a small, but statistically significant, increase in the incidence of both melanoma (HR, 1.30; 95% CI, 1.05 - 1.61) and breast cancer (HR, 1.16; 95% CI, 1.02 - 1.32) in this population.

"Bottom line, large prospective studies of populations with occupational exposure to low-level radiation are necessary," Novelli told Medscape Medical News.

In addition to interventionalists and support staff, patients are also exposed to radiation during the procedure.

For patients, the risk is developing a radiation injury on the skin, but as presenter Stephen Balter, PhD, professor of clinical radiology at Columbia University in New York City, told Medscape Medical News, this type of injury is only one of the "very small risks" compared with the other risks that procedures may have. Although the exact incidence is unknown, the occurrence rate of major radiation injury is estimated to be 1 in 10,000 to 100,000 procedures.

The real concern is that a physician, such as a dermatologist, will fail to recognize the skin effect as a radiation injury and decide to perform a punch biopsy. If the injury is deep, the biopsy tract may not heal, leading to infection, Balter explained.

Following Patients for Skin Injury

In the United States, the Joint Commission recognized this risk and released new requirements last January for organizations that offer fluoroscopy services.

Before the 2019 recommendation, organizations only had to capture the data on radiation exposure. "Now you have to follow the patient," said presenter Shelia Regan, MEd, of the Clinical Radiation Safety Office at Virginia Commonwealth University Health System in Richmond.

"A lot of people are just starting this now, but we’ve been doing it for five years," she told Medscape Medical News.

Regan receives real-time alerts for patients who obtain a radiation dose of over 5000 milligray and reviews their exposure history for the previous 6 months. If the patient received over 5000 milligray to an area, then a peak skin dose is calculated.

If the peak skin dose exceeds 5000 milligray, Regan follows the patient for 6 months. During this period, she calls four times and explains to the patient what to look for in terms of skin effects. She said that the purpose is to be proactive and catch a potential injury at the very early stages.

"That's the best course of action to take," she said.

Radiological Society of North America (RSNA) 2019 Annual Meeting: Abstract RC123B. Presented December 1, 2019.

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