Technical note: Energy dependence of the Gafchromic EBT4 film: Dose‐response curves for 70 kV, 6 MV, 6 MV FFF, 10 MV FFF, and 15 MV x‐ray beams

The dose-response curves for Gafchromic EBT4 films were nearly independent of the energy of the photon beams among 6 MV, 6 MV FFF, 10 MV FFF, and 15 MV. For very low-energy photons (e.g., 70 kV), a separate calibration from the same low-energy x-ray is necessary.