Technical note: Proton beam dosimetry at ultra‐high dose rates (FLASH): Evaluation of GAFchromic™ (EBT3, EBT‐XD) and OrthoChromic (OC‐1) film performances

Abstract

EBT3 and EBT-XD radiochromic films should be used with caution for the dosimetry of UHDR proton beams over 10 Gy. Their overresponse, which increases with mean dose rate and dose, could lead to non-negligible overestimations of the absolute dose. OC-1 films are dose rate independent up to 7500 Gy/s in proton beams. Films response is not impacted by the beam structure. A broader investigation of the usability of OC-1 films in UHDR conditions should be conducted at intermediate and higher mean dose rates and other beam energies.