Insights on the carbon footprint of radiotherapy in France

The French healthcare system is responsible for 8% of the national footprint. Achieving a net zero emissions scenario will require a 4-5 fold decrease of carbon emissions in the coming years. The carbon footprint of radiation therapy has not been specifically studied to date. In this review we summarize the content of the carbon footprint dedicated session at the annual meeting of the French society of radiation oncology (SFRO). We discuss the French healthcare system carbon footprint and its major drivers and our work on the estimation of the carbon footprint of external beam radiation therapy in the French setting. We developed a dedicated methodology to estimate the carbon footprint related to radiation therapies, and describe the main drivers of emissions based on a single centre as an example, namely patient's rides, accelerators acquisition and maintenance and data storage. Based on the carbon footprint calculated in our centres, we propose mitigation strategies and an estimation of their respective potential. Our results may be extrapolated to other occidental settings by adapting emission factors (kilograms of carbon per item or euro) to other national settings. External beam radiation therapy has a major carbon footprint that may be mitigated in many ways that may impact how radiation therapy treatments are delivered, as well as the national organization of the radiotherapy sector. This needs to be taken into account when thinking about the future of radiotherapy.