Interventional Imaging Systems in Radiology, Cardiology, and Urology: Energy Consumption, Carbon Emissions, and Electricity Costs.

Background: The energy demand of interventional imaging systems has historically been estimated using manufacturer-provided specifications rather than directly measured. Objective: To investigate the energy consumption of interventional imaging systems and estimate potential savings in such systems' carbon emissions and electricity costs through hypothetical operational adjustments. Methods: An interventional radiology suite, neurointerventional suite, radiology fluoroscopy unit, two cardiology laboratories, and two urology fluoroscopy units were equipped with power sensors. Power measurements logs were extracted for a single 4-week period for each radiology and cardiology system (all between June 1, 2022 and November 28, 2022) and for the 2-week period from July 31, 2023 to August 13, 2023 for each urology system. Power statuses, procedure timestamps, and fluoroscopy times were extracted from various sources. System activity was divided into off, idle (no patient in room), active (patient in room for procedure), and net-imaging (active fluoroscopic image acquisition) states. Projected annual energy consumption was calculated. Potential annual savings in carbon emissions and electricity costs through hypothetical operational adjustments were estimated using published values for Switzerland. Results: Across the seven systems, the mean power draw was 0.3-1.1 kW, 0.7-7.4 kW, 0.9-7.6 kW, and 1.9-12.5 kW in the off, idle, active, and net-imaging states, respectively. Across systems, the off state, in comparison with the idle state, exhibited a decrease in mean power draw of 0.2-6.9 kW (relative decrease, 22.2-93.2%). The systems had a combined projected annual energy consumption of 115,684 kWh (range, 3646-26,576 kWh per system). The systems' combined projected energy consumption occurring outside of the net-imaging state accounted for 93.0% (107,978/115,684 kWh) of projected total energy consumption (range, 89.2-99.4% per system). A hypothetical operational adjustment whereby all systems would be switched from the idle to off state overnight and on weekends (vs operated in idle mode 24/7) would yield potential annual savings in energy consumption of 144,640 kWh, carbon emissions of 18.6 MtCO2eq, and electricity costs of $37,896. Conclusion: Interventional imaging systems are energy intensive, with high consumption outside of image acquisition periods. Clinical Impact: Strategic operational adjustments (e.g., powering down idle systems) can substantially decrease interventional imaging systems' carbon emissions and electricity costs.