Medical Imaging's Climate Impact: Unnecessary Scans Contribute Significantly to Carbon Emissions
Key Insights
Unnecessary imaging scans for Medicare recipients alone generate up to 129 metric kilotons of carbon dioxide emissions annually, equivalent to powering a town of 70,000 people.
CT scans contribute approximately half of these excess emissions, with MRIs accounting for another quarter, according to research from the Harvey L. Neiman Health Policy Institute (search).
Climate change (search) is simultaneously increasing demand for medical imaging, with studies showing heat waves and air pollution raise X-ray (search) and CT scan (search) usage by approximately 5%.
A new study reveals that unnecessary medical imaging is contributing significantly to climate change (search), with Medicare recipients' inappropriate scans alone generating carbon dioxide emissions equivalent to powering a town of more than 70,000 people.
Researchers from the Harvey L. Neiman Health Policy Institute (search) analyzed data on imaging scans performed for nearly 30 million traditional Medicare beneficiaries between 2017 and 2021. Their findings show that reducing unnecessary imaging could cut carbon emissions by up to 129 metric kilotons annually.
"Our analysis demonstrates the potential to meaningfully reduce our carbon footprint by decreasing unnecessary imaging orders," said Elizabeth Rula, executive director of the Harvey L. Neiman Health Policy Institute (search) in Reston, Virginia.
The Carbon Footprint of Medical Imaging
The study, published in the Journal of the American College of Radiology, found that all imaging modalities produce substantial emissions. MRIs generate up to 136 kilotons of carbon dioxide, CT scans up to 178 kilotons, X-rays 46 kilotons, and ultrasounds 23 kilotons.
Lead researcher Dr. Gregory Cavanagh, a resident at Lahey Hospital & Medical Center (search), noted that these high-end estimates "also included the energy required when the scanners are in stand-by mode or in production phase between scans."
Previous research has estimated that approximately 26% of imaging scans ordered for Medicare patients are inappropriate. Of these unnecessary scans, CT scans contribute about half of the excess emissions, while unnecessary MRIs account for another quarter.
Climate Change Creating a Vicious Cycle
In a concerning feedback loop, climate change (search) itself appears to be driving increased demand for medical imaging. A separate study by Canadian researchers found that periods of extreme heat and air pollution increased demand for X-rays and CT scans by approximately 5%.
"While the individual daily effects we observed are modest, the cumulative increase in total imaging volumes is substantial," said Dr. Kate Hanneman, an associate professor at the University of Toronto's department of medical imaging, who led the Canadian research published in the journal Radiology.
The Toronto team tracked imaging use at four major hospitals from 2013 through 2022, analyzing nearly 1.7 million scans. They discovered that on days with peak outdoor heat and high levels of polluting particulate matter, daily X-ray (search) rates increased by 5.1% and CT scan (search) rates jumped by 4%. No similar trends were observed for ultrasound or MRI (search) usage.
Multiple Benefits of Reducing Unnecessary Scans
Experts emphasize that reducing inappropriate imaging would yield benefits beyond environmental protection.
"These findings add an additional, important reason to reduce inappropriate imaging utilization, which would also decrease the risk and cost to patients, cost to the healthcare system, and volumes contributing to the current radiology workforce shortage," Rula explained.
Dr. Julia Schoen, a clinical assistant professor at University of Michigan Health (search) in Ann Arbor, warned that "emissions are likely to continue to increase given sustained increases in overall imaging volumes over the past decade, and the potential for further increases related to climate-change related exposures and events."
Looking to the Future
As global temperatures continue to rise, medical facilities may need to prepare for increased imaging demands during extreme weather events. Dr. Hanneman noted, "Knowing the impact on our emergency departments will allow us to plan proactively."
The research highlights the interconnected nature of healthcare decisions and environmental impacts. Reducing unnecessary imaging represents an opportunity to simultaneously improve patient care, reduce healthcare costs, address workforce challenges, and combat climate change (search).
Healthcare providers are encouraged to follow appropriate use criteria for medical imaging and consider the environmental impact of diagnostic decisions alongside clinical factors. Patients should also be aware that "trendy" whole-body scans and other unnecessary imaging procedures carry not only personal health risks but environmental consequences as well.