Reducing Radiation Exposure in Medical Imaging: How Radiology is Making a Difference, One Patient at a Time

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Pei-Jan Paul Lin, PhD, chief medical physicist for Virginia Commonwealth University and VCU Health, collecting data for calculating peak skin dose. Source: VCU Health

Over the last 10 to 15 years, awareness of the risks of radiation exposure in medical imaging and efforts to reduce dose have escalated exponentially. Imaging equipment vendors have answered the call with dose-reducing strategies that include more sensitive image receptors, better image reconstruction techniques, dose alerts and post-processing software. Radiologists, technologists and physicists have been hard at work as well, edging down dose without compromising image quality. So where do we stand? Are we as low as we can go or is there more that can be done?

Leading by Example

The department of radiology at VCU Health in Richmond, Va., takes great pride in its efforts to improve patient radiation safety. The health system launched its Clinical Radiation Safety Initiative in 2012 and now has a Clinical Radiation Safety Office dedicated to creating “best practices for the use of ionizing radiation in an academic medical center.” As part of this commitment, VCU Health empowered two technologists with more than 60 years of combined clinical experience—Shelia Regan, BS, and Jan G. Clark, MEd—naming them the office’s clinical radiation safety educators. Regan and Clark monitor dose information within their department closely, spread the word at various industry conferences and provide special hands-on training for radiologists and technologists. They also developed an app that helps them look for “coaching opportunities” and praise employees who stand out for following safety guidelines and protocols.

“The fact that we have this clinical radiation safety office puts us ahead of the game nationally,” Regan says. “We’re excited to be at the forefront of what’s coming up for clinical radiation safety. Our entire enterprise goal for VCU Health is to be the safest hospital in the nation, so radiation safety fits right into that overall philosophy.”

Source: VCU Health
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VCU Health’s department-wide buy-in is evident with employees always on the look for a new way to reduce radiation dose. For example, one recent policy change reduced the number of pulses per second on the facility’s fluoroscopy systems from 15 to 10. It began with one radiologist, who made the shift and then closely examined the diagnostic quality of each image. When it was confirmed there was no drop in image quality, the department’s interventional radiologists all embraced the new parameter, reducing radiation dose by 33 percent for each patient. Regan and Clark monitored this shift in protocol, comparing data before and after the change was made in December 2016. The number of system alerts for breached radiation thresholds was 15 in September 2016 and 14 in October 2016, dropping to just six in January 2017 and eight in February 2017. Clark says her team “could clearly see that there was a reduction in patient exposure due to this physician-driven change.”

Though the Clinical Radiation Safety Office is still relatively new, its reputation has spread quickly. A neighboring health system recently sent an entire team—including administrators, a physicist and an IT specialist—to VCU Health for guidance on improving and maintaining radiation safety practices. Regan and Clark enjoy these opportunities to help other providers and see the efforts as a big victory for patients.

A Change in the Culture

Specialists throughout the country are committed to the same goals as well, using a number of different techniques and strategies to lower dose at their own facilities.

“The culture change in the United States regarding the amount of radiation use in a CT scan has been very significant and very noticeable,” says Richard L. Morin, PhD, Brooks-Hollern Professor in the department of diagnostic radiology at the Mayo Clinic in Jacksonville, Fla. “There are now practices where the radiologists know exactly what their dose index is for a variety of exams.”

Statistics show the culture change is making a difference. In a recent JAMA Internal Medicine study, for example, the authors found that after reviewing best practices at five University of California medical centers, “the number of CT scans that had an effective dose measurement that exceeded benchmarks was reduced considerably by 48 percent and 54 percent for chest and abdomen, respectively.” Also, the mean effective dose for abdominal CT decreased from 20 to 15 mSv, a reduction of 25 percent (JAMA Intern Med. 2017 Apr 10).

A 2010 article from the Journal of Cardiovascular Computed Tomography provides additional evidence of the shift: “Scanner manufacturers, researchers and clinicians performing coronary CT angiography have taken the challenge of radiation dose reduction seriously. There has been extraordinary research and clinical progress over the past five years, with research and clinical doses falling by as much as 50 percent every two years” (J Cardiovasc Comput Tomogr. 2010 Nov-Dec;4(6):365-74).

So what brought on the change? Literature on the topic published in the early 2000s helped the trend build momentum, says Mahadevappa Mahesh, MS, PhD, professor of radiology and cardiology at Johns Hopkins University School of Medicine in Baltimore. Mahesh, who also works as a chief physicist at Johns Hopkins Hospital and professor of environmental health at Johns Hopkins Bloomberg School of Public Health, cites research on CT techniques for pediatric patients as an early example of this influence. Protocols were often the same for adult patients and pediatric patients at the time, but once more and more specialists read that research, protocols started to change throughout the industry.

Mahesh also points to a well-known study published in 2009 by the National Council on Radiation Protection and Measurements (NCRP) as being influential. NCRP Report No. 160, Ionizing Radiation Exposure of the United States Population, found that medical radiation exposure had increased more than 600 percent since the 1980s. Mahesh was a member of the NCRP Scientific Committee that published the report. “We knew that was going to draw a lot of attention, and it did,” he says. “CT was now contributing almost half of the medical imaging [radiation] exposure.” Enough time has passed since that original report that the NCRP is now looking to publish an updated study with new research. It should be quite telling, Mahesh notes, because it will help verify if everyone’s hard work has paid off.

Various news stories also helped shape the dialogue on radiation dose in the United States, and the shadow of one infamous incident still looms large throughout the industry. In 2008, a 2-year-old boy was brought into a small hospital in Arcata, Calif., after he fell out of bed and was unable to properly move his head. Due to errors by the hospital’s technologist, the child was exposed to 151 different scans instead of the normal number, which is closer to 25. The boy started showing physical signs of the radiation overdose almost immediately, though no long-term effects were ever reported, and his family eventually reached a settlement with the hospital.

Stephen Balter, PhD, professor of radiology and medicine at Columbia University Medical Center in New York City, says the incident in Arcata was an example of what happens when a technologist doesn’t focus enough on keeping repeat scans to a minimum. “The tech thought she did one or two repeats, but they found she had actually done more than 10 repeats,” he says. “Digital imagers make it easy to become unaware of repeats. Better tools are needed to keep track of pictures that were taken, but didn’t go to PACS.”

Media outlets such as the New York Times picked up this story, putting radiation exposure on the minds of parents and patients throughout the country. The incident’s impact is still being felt to this day: it may have occurred almost a full decade ago, but it still comes up in conversation regularly when discussing the potential harms of radiation in imaging.

Putting in the Work: Training and Quality Control

Specialists work to lower radiation dose in a variety of ways, but it all starts with serious, dedicated training. As trainees learn more about their equipment and how certain methods can lead to reductions in dose, it builds a foundation that will later help them experiment and discover new, innovative ways to keep doses down.

Even one straightforward change in a procedure protocol can lead to a noticeable reduction in dose. For instance, CT exams included an anteroposterior localizer image for many years. Morin explains that one side effect of this was the breast received the entrance dose instead of the exit dose, increasing the amount of radiation to the patient. Procedures were modified over time, and providers started implementing a posteroanterior projection, which led to a noticeable reduction in dose.

Quality control also is crucial, Morin adds. Equipment should be inspected before a patient enters the room, not while he or she is being scanned. “You don’t want to discover you have a detector that is unbalanced with your first patient,” he says. “You want to find out before you even start seeing patients.”

Because of the technologist’s proximity to both the equipment and the patient, his or her training also plays a key role. “The technologist is the finger of this whole imaging body,” Mahesh says. “My emphasis is getting the tech to understand the system he or she is operating.”

Mahesh notes that a properly trained technologist helps the entire department run smarter and more efficiently; the technologist should know each scanner inside and out.

The Joint Commission also has been effective at keeping radiation levels low, pushing radiologists forward in terms of specific training techniques and documentation. Regan cites requirement PI.02.01.01 EP 6—which says “incidents where radiation dose indices exceeded expected dose index range are reviewed and analyzed”—as one example of how Joint Commission rules have evolved over time. This update is also noteworthy, she adds, because it applies specifically to CT while many other requirements focus on fluoroscopy.

Regan appreciates how the Joint Commission inspects facilities to make sure these different requirements are being followed. “They don’t want you to just pull out your policy book and say, ‘We have that in place,’” she says. “They want to see the end result. They don’t want you to just give lip service to the concept.”

How Administrators Can Help

Administrators can make an impact on dose as well by doing everything in their power to ensure radiologists aren’t being asked to rely on old, outdated technology and being sure policies are followed.

Balter believes providers must consider the positive impact that bringing newer equipment into the fold can have on radiation dose and patient safety. The average age of advanced imaging equipment in many facilities is pushing 7 to 10 years, and some basic radiographic rooms have been unchanged for 20 to 25 years.

Balter compares it to owning an older cell phone vs. something brand new. A phone from several years ago will help you make calls, but you miss out on huge advances in technology that are common on newer models. The same holds true for imaging equipment, he says, especially when you look at what vendors have done in the last several years when it comes to reducing dose. “I’m not an administrator, but equipment replacement to exploit improving technology should be on the table,” Balter says.

Regan and Clark also believe administrator buy-in is vital. Clark says they are excited to share their message with administrators at AHRA 2017 in Anaheim, Calif., and she hopes their success at VCU Health will help other providers take that next step forward.

“Administrators are the ones who have their fingers on the budget and they can make things happen in their facilities,” Clark says. “Once they see that it can be done and how important the monitoring and lowering of patient dose is, we can be a benchmark for them developing similar programs in their own facilities.”

If administrators need additional assistance pushing their facilities to invest in lowering dose, they can always point to the potentially huge cost savings that could come as a result. Purchasing newer equipment and putting more resources toward updating protocols can help eliminate repeat imaging, which can be quite costly for providers. Consider a study from 2015 that documented how health information exchange (HIE) use can cut down on repeat imaging and save providers more than $32,000 each year (J Am Coll Radiol. 2015 Dec;12(12 Pt B):1364-70). Cutting down repeat imaging in other ways could potentially bring about similar savings.

Finding Balance

When discussing the various ways radiologists are reducing dose, Morin warns that there is a point where it’s possible to take things too far and do harm to the patient.

“It’s important to realize it isn’t good enough to just decrease the amount of radiation, because if the image becomes so noisy that a competent interpretation can’t be rendered, then you haven’t done the patient any favors,” he says. “Something else will have to happen with that patient, either another test using ionized radiation or another test that may be more difficult or extensive.”

This possibility also worries Mahesh, who says he has watched over the last decade as awareness and concern over radiation safety have shifted from “the extreme left” all the way to “the extreme right.” He once wrote extensively about lowering dose, but Mahesh says he is now “trying to bring the pendulum back to the center point, emphasizing radiation dose optimization rather than dose reduction.”

“Some enthusiastic physicians have the right goals in mind and want to keep risk as low as possible, but they don’t understand the balancing point between image quality and dose,” he adds. “I’ve seen some images where the quality was quite low and the physicians are struggling to find the pathology. I don’t think that’s necessary.”

Based on their experience over the years, Regan and Clark aren’t as concerned about dose reduction going so far that images are noisy because the individuals interpreting the images still have the final word. “The radiologists are not going to let the quality go down,” Clark says.

Looking ahead

Clark is confident radiation doses will continue to get lower and lower, and part of this success will be due to technology while the rest will be due to people and processes. “At some point in the future, we’ll all have a central repository of our images somewhere,” she says. “That would be phenomenal, because as a large trauma center, sometimes we get people who come in from a small hospital somewhere and they can’t get those images to us, so they have to have those images repeated.”

Morin agrees with Clark’s confident outlook and thinks the best is yet to come as far as lowering dose is concerned.

“This is a very interesting and exciting time, because we’re now seeing doses change in a very positive way for the patient,” Morin says. “We’re saving many, many lives by using CT scans appropriately and making diagnoses early when treatment is still an option.”

How to Learn More

These are just some of resources are available for radiologists, technologists, physicists, administrators and trainees looking for more information on how they can reduce radiation dose at their own facilities.