Radiology for a Healthy Planet
By Beth W. Orenstein
Radiology Today    
Vol. 24 No. 4 P. 10

Radiology is examining its impact on climate change.

It is not without irony that health care activity contributes to climate change, says Jonathan Gross, MD, an associate professor of radiology at Texas Children’s Hospital/Baylor College of Medicine in Houston. At the same time, “We, as physicians, are trying to give patients optimal care and do no harm,” he says. “But, because of our wastefulness, we are contributing to the overall poor health of our planet.” Indeed, the World Health Organization estimates that from 2030 to 2050, climate change is expected to cause an additional 250,000 deaths each year from climate-caused conditions such as heat stress, diarrhea, malaria, and malnutrition. 

Evidence of health care activity’s role in climate change is growing. Health care in the United States alone contributes to 8.5% of total US greenhouse gas emissions, according to a report published in December 2020 in Health Affairs. Greenhouse gas emissions, scientists say, warm the planet. The global health care system “emits more than 2 gigatons of CO2 emissions annually and is estimated to account for 4% to 10% of total greenhouse gas emissions in developed nations,” says Kate Hanneman, MD, an associate professor of radiology at the University of Toronto. Medical imaging is a major contributor to those health care related emissions, says Hanneman, who moderated and spoke at a session on radiology’s impact on climate change at RSNA 2022 in Chicago.

Radiology is a significant energy user. Advanced diagnostic imaging equipment—MRI, CT, ultrasound, nuclear medicine—is the largest contributor to energy usage within radiology departments, according to a commentary published in July 2021 in Radiology. A Swiss study published in June 2020 in Radiology found that the energy to power four MRI machines and three CT scanners over the course of one year, with their associated cooling systems, was equivalent to that required to power a town of 852 people at a cost of approximately $200,000, Hanneman says. Even when not in use, imaging equipment requires a significant amount of energy, says Reed Omary, MD, MS, the Carol D and Henry P Pendergrass professor and chair of radiology and radiological sciences at Vanderbilt University Medical Center in Nashville, who spoke at the RSNA 2022 session. About two-thirds of a CT scanner’s energy use occurs during its idle state, the Radiology commentary estimates. 

In IR suites, the largest source of greenhouse gas emissions is the energy used to maintain climate control, followed by emissions related to singleuse surgical supplies, says Gross, who also spoke at the RSNA discussion. Gross is a corresponding author of a study on the environmental impact of a hospital-based IR department published in June 2021 in the Journal of Vascular and Interventional Radiology.

Given the numbers and the potential harm, those in medicine, including radiology, have begun to ask: What can we do to reduce our impact on climate? Radiology appears to be leading the way in this discussion and in taking action. The Association of University Radiologists annual meeting, held in March 2022 in Phoenix, was centered on the theme: “Sustainability, Climate Change, and Radiology.” According to Omary, who is president of the Association of University Radiologists, the meeting drew high praise from Amy Collins, MD, an emergency physician and sustainable health care professional who serves as the medical director for physician engagement and education at Health Care Without Harm. Collins told Omary that she was not aware of another specialty that has had a theme of climate change and sustainability for its entire meeting.

Radiology is well positioned to be a sustainability leader in health care because “we interact with almost every other specialty,” says Maura Brown, MD, a clinical assistant professor of radiology at the University of British Columbia in Vancouver and another of the five speakers at the RNSA session. “Thanks to our interactions with other clinicians and patients, we have many opportunities to collaborate and discuss how we can work together to create a healthier and stable climate,” she says.

Omary agrees: “Everything in health care comes through us in radiology. We touch nearly every patient, and because of that central location within the health care system, we have an opportunity to have an outsized impact on this issue.”

Sustainable Practices
During the discussion at RSNA, the radiologists spoke about health care practices that are healthier for the planet and how they should be implemented. Some of what they talked about could apply to all medical fields, and some were specific to radiology.

Their sustainable-practice suggestions for medicine, in general, include the following:

• Serve more plant-based meals at conferences and meetings and throughout the health care system.
• Purchase electric vehicles (EVs). The Inflation Reduction Act that President Biden signed into law on August 16, 2022, expands tax credits to help health systems transition their automotive fleets to EVs as well as install EV charging infrastructure.
• Hold meetings, conferences, and patient interactions virtually when possible. Virtual meetings eliminate travel and the associated use of fossil fuels, Brown says. “The carbon footprint of in-person conferences is large, and radiologists might consider choosing hybrid or virtual conferences, when possible,” she says. Brown says the authors of an article published in February 2020 in The Lancet Planetary Health make persuasive arguments that carbon-neutral medical conferences should be the norm. Many in health care have become accustomed to virtual meetings during the height of the COVID-19 pandemic, Gross says, and could see the benefits of virtual gatherings, telemedicine consultations, and patient appointments. “I think,” he says, “it is very realistic for us to hold at least hybrid meetings regularly where people have the option of attending in person or remotely.”
• Switch to energy-efficient LED lighting throughout the facility.
• Optimize indoor climate control.
• Reduce or eliminate plastics and Styrofoam packaging as much as possible. Omary says his department recently announced it was no longer going to provide plastic water bottles.

The June 2021 study in the Journal of Vascular and Interventional Radiology concluded that the majority of greenhouse gases that IR practices generate come from the energy used to maintain climate control. The second leading source was the IR department’s use of single-use surgical supplies. It is possible to manufacture IR products and package them in ways that reduce waste without sacrificing safety or increasing cost, Gross says.

Research in IR has found that more than 50% of packaging by weight is redundant. “I think there is a lot of room to improve in this area,” Gross says. Much of the packaging material for surgical supplies is already potentially recyclable. However, much of it gets tossed in general waste bins. “Manufacturers should be encouraged to design less wasteful packaging, and staff in IR suites should be trained on appropriate sorting of waste to maximize recycling,” Gross says. He adds that some supplies, even contrast agents, could be purchased in larger containers and apportioned in smaller units when needed. In addition, Brown says, manufacturers must consider ways of transporting supplies and equipment to users that generate less greenhouse emissions.

Included among the panelists’ radiology- specific suggestions are the following:

Eliminate unnecessary scans.
Radiologists already apply the ALARA principle, “as low as reasonably achievable,” to studies that use ionizing radiation. “Development and adoption of appropriate use and clinical decision support tools can help reduce unnecessary exams,” Hanneman says.

Compared with CT and MRI, ultrasound uses the least energy and has the least environmental impact, according to a pilot study published in October 2018 in the Journal of the American College of Radiology. Could an ultrasound be done to get the same answers as a CT or MRI? “If you have one or two patients where you say, ‘OK, we’ll do ultrasound instead of the more energy intensive CT or MRI,’ it wouldn’t have much of an impact,” Gross says. “But if this were to be adopted globally, then it could start to have a massive impact.” Also, Gross says, “If all of us opt for the lower energy modality over the higher energy modality when appropriate, we could save a tremendous amount of energy.” He cites a study published in June 2020 in Radiology that reached the same conclusion.

Consider energy usage when buying or updating equipment.
Radiologists, the EPA, and the imaging equipment industry are working toward devising an “Energy Star” rating system for MRI and CT scanners, similar to the one that exists for dishwashers, refrigerators, and other household appliances, Omary says. Radiology departments looking to upgrade or replace their machines can ask that potential vendors include information about their scanners’ environmental footprint in their proposals, Omary says. “Our purchasing decisions can have an immense impact, and when we choose scanners, we need to base those decisions not just on cost but also on their environmental impact.”

Omary notes that the three largest manufacturers of imaging equipment— Siemens, Philips, and General Electric— “all are addressing environmental concerns in different ways. And they are very willing to partner with radiology departments on addressing energy concerns.” Gross adds that, given their purchasing power, health care systems can pressure vendors to make their equipment more energy efficient. In addition, updating and maintaining existing imaging equipment to extend the lifespan where possible and appropriate could be more environmentally friendly than replacing entire machines, Brown says.

Adopt strategies that reduce energy consumption when scanners are idle.
In the Swiss study, researchers found that two-thirds of a CT scanner’s energy consumption takes place when the scanner is idle. For an MRI, according to the study, one-third of its energy consumption can be attributed to periods of time when it was not in use. Could patients be scheduled in such a way that downtime is reduced?

“We can collaborate with vendors to improve and automate energy efficiency modes when our scanners are idle,” Hanneman says. Gross says that perhaps it would be possible to allow the temperature and humidity in the IR suite to drift within a wider range—even a few degrees—overnight or on weekends when machines are idle, to reduce their energy consumption.

Sustainability Gaining Traction
Hanneman says it is imperative that health care and radiology address sustainability sooner rather than later. “Climate change results in adverse health effects and disproportionately affects those already vulnerable due to social, environmental, and public health factors,” she says. “As global temperature increases, extreme weather events, including storms, floods, and heat domes, will become more frequent and result in severe and potentially devastating effects, including deaths. Climate-sensitive extreme weather events also can negatively impact health care access and increase the financial burden for institutions.”

While health care systems have been slow to address their energy contributions and inefficiencies, Hanneman says, “There is a growing movement to address sustainability in health care and specifically in radiology.” The RSNA 2022 session “Climate Change and Radiology” was sponsored by the RSNA Professionalism Committee, which she chairs. When Hanneman reached out to potential speakers, all were eager to participate, she says. RSNA has approved a similar session for 2023’s annual meeting, as well, she says. The need to address climate change from a health care perspective “is gaining traction within other societies as well,” Hanneman says.

In a letter to the editor published in May 2022 in Radiology, Gross wrote that rethinking current practices in diagnostic radiology and IR and adopting new approaches to address the climate crisis is no doubt challenging. “If we want to stay true to one of the core missions of health care—to minimize harm—we really need to rethink our practices. If we don’t, all of our health is going to suffer,” he adds. Gross believes, however, that adaptability and innovation are core characteristics of radiology, and he has no doubt that the field is “up to the challenge.”

— Beth W. Orenstein of Northampton, Pennsylvania, is a freelance medical writer, a regular contributor to Radiology Today, and the owner of an electric vehicle.