The Department of Radiology at Nashville, Tenn.-based Vanderbilt University Medical Center and Amsterdam-based Royal Philips found that imaging equipment accounts for more than 50% of the department's greenhouse gas emissions.
The study, published Nov. 26 in Radiology, conducted a 10-year, process-based life-cycle assessment of VUMC's diagnostic radiology department, which serves adult inpatient, outpatient and emergency department patients. Researchers analyzed the production and distribution of imaging equipment; energy use of equipment including MRI, CT, radiography, fluoroscopy and ultrasound; production and use of other capital equipment; production of single-use, semidurable and durable supplies and linens; and production and energy use from onsite data storage. The study excluded nuclear medicine, interventional radiology and breast-imaging services.
Researchers estimated that diagnostic services generate 4.6 kilotons of carbon dioxide annually — equivalent to the emissions from nearly 1,100 gasoline-powered cars, according to a Dec. 1 system news release.
MRI accounted for the largest share of emissions at 48%, followed by CT at 24%; X-ray and fluoroscopy at 12%; general department workstations, PACS and data storage collectively at 12%; and ultrasound at 4%.
Of the total emissions, 54% came from the energy use of imaging equipment, 22% from the production of imaging equipment and the use of onsite and remote workstations, 10% from the production and use of linens and 8% from the production of disposable supplies.
"A key finding is most of our carbon emissions with CT occurred when we were not imaging patients — during downtime," John Scheel, MD, PhD, professor of radiology and vice chair of global health in the department of radiology and radiological sciences at VUMC, said in the release. "Now we can work with colleagues to reduce our per-patient waste by imaging more patients in a scheduling block. At the same time, we can collaborate with our industry partners to develop CT software and hardware upgrades to reduce energy use, thus carbon emissions, during downtime."