Tracking and Reducing SF Usage in Radiation Oncology: A Step Toward Net-Zero Health Care Emissions.

Sulfur hexafluoride (SF) is a widely used insulating gas in medical linear accelerators (LINACs) due to its high dielectric strength, heat transfer capabilities, and chemical stability. However, its long lifespan and high Global Warming Potential (GWP) make it a significant contributor to the environmental impact of radiation oncology. SF has an atmospheric lifespan of 3200 years and a GWP 23,000 times that of carbon dioxide. The amount of SF that can be emitted through leakage from machines is also concerning. It is estimated that the approximate 15,042 LINACs globally may leak up to 64,884,185.9 carbon dioxide equivalent per year, which is the equivalent greenhouse gas emissions of 13,981 gasoline-powered passenger vehicles driven for 1 year. Despite being regulated as a greenhouse gas under the United Nations Framework Convention on Climate Change, SF use within health care is often exempt from regulation, and only a few states in the United States have specific SF management regulations. This article highlights the need for radiation oncology centers and LINAC manufacturers to take responsibility for minimizing SF emissions. Programs that track usage and disposal, conduct life-cycle assessments, and implement leakage detection can help identify SF sources and promote recovery and recycling. Manufacturers are investing in research and development to identify alternative gases, improve leak detection, and minimize SF gas leakage during operation and maintenance. Alternative gases with lower GWP, such as nitrogen, compressed air, and perfluoropropane, may be considered as replacements for SF; however, more research is needed to evaluate their feasibility and performance in radiation oncology. The article emphasizes the need for all sectors, including health care, to reduce their emissions to meet the goals of the Paris Agreement and ensure the sustainability of health care and our patients. Although SF is practical in radiation oncology, its environmental impact and contribution to the climate crisis cannot be ignored. Radiation oncology centers and manufacturers must take responsibility for reducing SF emissions by implementing best practices and promoting research and development around alternatives. To meet global emissions reduction goals and protect both planetary and patient health, the reduction of SF emissions will be essential.