Energy Consumption Profiles of Common Types of Medical Imaging Equipment in Clinical Settings

Imaging equipment such as MRIs, CT scanners and general radiography equipment consume significant amounts of energy while operating. This study describes a series of detailed energy consumption studies on these devices during clinical use at three major health care centres in Canada, one in British Columbia and two in Ontario. The study was conducted by the Canadian Coalition for Green Health Care [1], with funding provided by Natural Resources Canada [2] and BC Hydro [3]. The primary goal of the study was to accelerate the development of ENERGY STAR specifications for medical imaging equipment. Natural Resources Canada is assisting the United States Environmental Protection Agency (US EPA) [4], by collecting these data from the field. Eight testing events were undertaken, providing energy consumption data for low power energy modes, standby/idle power energy modes and active/patient scanning energy modes. Energy consumption was measured over periods ranging from three to eleven days, to provide rich information about when and how frequently the equipment was used and what the associated energy consumption profiles were. Data acquisition rates were varied to gain a detailed understanding of the temporal variations in energy consumption profiles during each use mode. Results from this study showed that there were variations in the low power mode energy consumption of greater than 25% in some cases, and that non-scanning energy consumption, either low power or stand-by modes, in some cases accounted for up to 80% of the total energy consumption of the system at some hospitals. These findings indicate that there is considerable scope for manufacturers to reduce the energy consumption levels of their devices, and for users to reduce energy consumption during clinical use through practices such as placing the system into a lower energy mode or shutting it down while not in use, where possible.