Idle Intervention: Powering Down IR Systems Cuts Consumption and Cost

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Jan Vosshenrich, MD
Department of Radiology
University Hospital Basel, Switzerland

The health care sector—and especially medical imaging—greatly contributes to global greenhouse gas emissions. Recent research has highlighted the colossal energy appetite of CT and MRI scanners, spotlighting substantial nonproductive energy waste during idle periods (1–3). 

But do interventional radiology and interventional cardiology face similar energy consumption challenges? 

To find the answer, my University Hospital Basel colleagues from the departments of radiology, cardiology, urology, and building management equipped interventional imaging devices with power sensors and calculated their energy demand, carbon emissions, and annual costs (4). 

The idle power consumption of CT scanners and basic fluoroscopy devices (e.g., used for peripherally inserted central catheter line insertions) is around 3 kilowatt-hours (kWh). Biplanar angiography devices used in interventional radiology and catherization labs have around 2–2.5 times higher power requirements, ranging between 5–7.5 kWh (Fig. 1)

Fig. 1—Mean power draw in kilowatts (kW), stratified by system and activity states. Error bars represent SDs. Values for net imaging state were estimated and lack SDs. Dashed horizontal lines represent mean power draws in off and idle states of CT scanner and of MRI scanner without power-saver mode, based on published data. EP = electrophysiology, INR = interventional neuroradiology, IR = interventional radiology, OR = operating room, lab = laboratory, cath = catheterization

Simply powering down these devices when not in use decreased power consumption and increased energy efficiency by 22–93%. System shutdowns could be safely practiced without causing damages, affecting the systems’ lifespan, or voiding service warranties.  

Vendors have started to encourage customers to consistently power down systems overnight and during idle periods longer than an hour in their best practice guidelines. If you do not already shut down your imaging devices, our AJR Original Research article includes projected annual savings for doing so. 

On a device level, consistently powering down idle-running devices overnight and on weekends may save up to 39,000 kWh in energy consumption, 5 metric tons in greenhouse gas emissions, and $10,000 in electricity costs.

For multiple devices, savings add up!

Based on their institutional setting, we estimated combined annual savings of 144,640 kWh in energy consumption, 18.6 metric tons in greenhouse gas emissions, and $37,896 in electricity costs. The included cost and carbon emission sensitivity analyses allow radiology, cardiology, and urology departments to estimate their potential cost savings and sustainability benefits, depending on local electricity prices and carbon intensities accordingly.

Savings vary with usage patterns and may be lower for practices offering around-the-clock emergency procedures. However, switching off can still pay off without sacrificing readiness and prompt care, given short start-up and shutdown times of modern devices (ca. 2–5 minutes).

But even when consistently powering down idle-running systems (Fig. 2), most of the devices’ energy consumption still occurred inactively without a patient being in the room for a procedure (overall: ~60%, range for individual devices: ~41-96%.)

Fig. 2: Projected annual inactive and active energy consumption (i.e., energy consumption occurring outside of and during procedures, respectively). Dashed horizontal lines represent mean annual energy consumption of 4-person household and of CT scanner, based on published data. EP = electrophysiology, INR = interventional neuroradiology, IR = interventional radiology, OR = operating room, lab = laboratory, cath = catheterization

Given how the energy consumption of the devices is distributed, we concluded that there is much room left to further improve sustainability in interventional radiology. However, these would require technical innovations and more eco-friendly designs from the systems’ manufacturers. 

In summary, interventional imaging systems are energy intensive in their operation. The annual energy demand of each device is as high as that of 1 to 5 4-person households. Nonproductive energy consumption outside procedures is disproportionately high. Powering down idle-running devices can decrease costs and increase sustainability. Meanwhile, system shutdowns and start-ups can be safely and quickly performed. However, technical innovations are needed to further improve sustainability in interventional radiology writ large.

For more reasons why now is the perfect time to ramp up your sustainable imaging efforts, “the yellow journal” has since published multiple Editorial Comments for our full-length manuscript—authored by individuals who served as the article’s peer reviewers before acceptance (i.e., those most familiar with its content). AJR Editorial Comments by Nadja Kadom [5] and by Katherine Frederick-Dyer [6] offer insights from different perspectives regarding the energy consumption of interventional imaging equipment. It’s worth noting, too, that the AJR Global team has published Chinese and Spanish translations, both PDF and audio files, for our article’s abstract.

References

  1. Brown M, Schoen JH, Gross J, Omary RA, Hanneman K. Climate change and radiology: impetus for change and a toolkit for action. Radiol 2023 May; 307:e230229
  2. Picano E, Mangia C, D’Andrea A. Climate change, carbon dioxide emissions, and medical imaging contribution. J Clin Med 2022 Dec 27; 12:215
  3. Brown M, Snelling E, De Alba M, Ebrahimi G, Forster BB. Quantitative assessment of CT energy use and cost savings through overnight and weekend power down in a radiology department. Canadian Association of Radiologists Journal 2023; 74:298–304
  4. Vosshenrich J, Mangold D, Aberle C, et al. Interventional imaging systems in radiology, cardiology, and urology: energy consumption, carbon emissions, and electricity costs. AJR 2024 Mar 20 [published online]. Accepted manuscript. doi:10.2214/AJR.24.30988
  5. Kadom N. Editorial comment: The time to start is now. AJR 2024 Mar 27 [published online]. Accepted manuscript. doi:10.2214/AJR.24.31188
  6. Frederick-Dyer K. Editorial comment: Let’s not be idle about idle power consumption. AJR 2024 Apr 3 [published online]. Accepted manuscript. doi:10.2214/AJR.24.31222
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