Imagine this: every year, millions of liters of substances used in medical imaging are washing into our rivers, oceans, and even our drinking water. It’s a hidden environmental crisis that’s been quietly growing for years. A groundbreaking study published on December 5 in JAMA Network Open reveals that between 2011 and 2024, a staggering 13.5 billion milliliters (mL) of contrast media were administered to Medicare beneficiaries during 169 million advanced imaging exams like CT and MRI scans. But here’s where it gets controversial: these contrast agents, while essential for diagnosing diseases, are non-renewable resources that linger in the environment long after they’ve served their purpose.
Lead researcher Florence Doo, MD, from the University of Maryland in Baltimore, teamed up with experts from the Harvey L. Neiman Health Policy Institute (HPI), NYU Langone, Oxford University, and Imperial College London to uncover the scale of this issue. ‘Contrast agents don’t just vanish after use,’ Doo explains. ‘Iodine and gadolinium end up in wastewater, accumulating in ecosystems and potentially affecting public health.’ And this is the part most people miss: while these substances are critical for medical imaging, they’re also ‘persistent pollutants’ that standard wastewater treatments can’t fully remove.
The study analyzed U.S. Medicare Part B fee-for-service claims from 2011 to 2024, focusing on imaging procedures like CT, CT angiography, MRI, and MR angiography. Using standard doses (100 mL for iodinated agents and 15 mL for gadolinium-based agents), the team found that Medicare beneficiaries underwent 169 million contrast-enhanced exams across 82 procedure codes. These scans consumed a whopping 13.5 billion mL of contrast media—a number that’s hard to ignore.
Here’s the kicker: the annual use of contrast media isn’t slowing down. From 2014 to 2019, the volume of iodinated agents grew by 5.2% yearly, while gadolinium agents increased by 3.5%. Even the COVID-19 pandemic, which caused a temporary dip in 2020, saw a sharp rebound in 2021 with growth rates of 10.8% and 10.1%, respectively. Iodinated agents dominated the total volume at 12.9 billion mL (95.6%), with CT scans of the abdomen or pelvis being the biggest culprit at 4.4 billion mL. For gadolinium, brain MRIs topped the list at 221 million mL.
But it’s not all doom and gloom. Doo’s team highlights ‘actionable mitigation strategies’ to reduce this pollution, such as ensuring imaging orders are clinically necessary, using weight-based dosing to avoid overuse, and adopting multiuse vial systems. Emerging solutions like biodegradable contrast agents and AI reduction algorithms show promise, though they’re still experimental and need rigorous testing. The question is: are we doing enough to balance medical necessity with environmental responsibility?
‘We can’t turn a blind eye to the environmental impact of medical imaging,’ Doo urges. ‘Contrast stewardship isn’t just about patient care—it’s about protecting our planet.’ This approach should be a cornerstone of healthcare sustainability efforts. But here’s a thought-provoking question for you: as we advance medically, are we inadvertently harming the very environment we depend on? Share your thoughts in the comments—let’s spark a conversation about this critical yet overlooked issue.
For the full report, visit https://www.doi.org/10.1001/jamanetworkopen.2025.47304.
Disclosure: Doo’s research was supported by grants from the National Institutes of Health Clinical and Translational Science Award Program and the Association of Academic Radiology Clinical Effectiveness in Radiology Research Academic Fund, partially funded by GE Healthcare https://www.auntminnie.com/resources/vendors/company/15553507/ge-healthcare.
