Green radiology (part 1): environmental sustainability and energy consumption in medical imaging, with perspectives from Japan.

Climate change is an important public health challenge, and healthcare itself contributes to greenhouse gas emissions. Within healthcare, radiology is energy intensive because modern imaging services require high-power equipment, cooling systems, digital infrastructure, consumables, and continuous operational readiness. This review summarizes current evidence on the environmental footprint of radiology and discusses practical strategies for implementing Green Radiology, with particular attention to Japan. Life cycle assessment studies indicate that the operational phase of imaging systems, especially electricity use, is an important contributor to radiology-related emissions, while non-productive idle periods represent a key opportunity for mitigation. MRI, CT, interventional radiology, picture archiving and communication systems, workstations, and emerging artificial intelligence (AI)-related infrastructure each contribute to this footprint in different ways. Practical measures include equipment power management, workflow optimization, protocol optimization, energy-aware information technology management, careful implementation of AI, and reduction of low-value imaging, many of which may also improve operational efficiency and reduce costs. However, these strategies must be implemented with attention to emergency readiness, scanner warm-up requirements, diagnostic accuracy, patient safety, and clinical workflow. In Japan, high CT and MRI scanner density with relatively low per-scanner utilization may increase non-productive energy use, but broad equipment distribution also supports accessibility, regional equity, and emergency preparedness. At the system level, reducing the environmental footprint of radiology in Japan therefore requires balanced regional coordination, shared resource utilization, selective consolidation where appropriate, and effective allocation of limited radiologist resources. Green Radiology should aim to reduce avoidable environmental burden while maintaining diagnostic accuracy, patient safety, equitable access to medical imaging, and high-quality patient care.