Study of Air Activation in the First Public Proton Therapy Center Planned in Spain at the Marques de Valdecilla University Hospital (HUMV) in Santander

The main advantage of using proton beams in radiotherapy lies in the physi-cal characteristic of protons, linked with the dose distribution pattern defined by the so-called Bragg plot. Considering these benefits, there has been a signifi-cant expansion of centers worldwide in recent years, with currently 108 proton therapy centers in operation, 33 under construction, and 38 in the planning sta-ge (PTCOG, 2022).Based on International Basic Sa-fety Standards and Regulatory Princi-ples (IAEA, 2020), main radiological risks in proton centers have been wi-dely stated and summarized (Yonekura et al., 2016):1. External exposure to secondary radiation (neutrons and photons) from beamline.2. External exposure from activated equipment, materials of the facility, water and air.3. Internal exposure for inhalation of radioisotopes in activated air.