An overlooked source of skin dose perturbation: Commercial tattoo inks in radiotherapy
Fig 2
Modality- and energy-dependent dose enhancement factors (DEF) for Fe2O3-dominant brown tattoo pigment.
(a) 6 MeV and (b) 18 MeV electrons, and (c) 6 MV and (d) 18 MV photons. Electron beams produce modest perturbations, with 6 MeV showing enhancement (peak DEF ~ 1.07) while 18 MeV exhibits dose deficits (DEF < 1.0). In contrast, photon beams generate pronounced enhancement (peak DEF ~ 2.2–2.5) driven by high-Z-mediated secondary electron production. Curves shown here for 5%, 10%, 25%, 50%, 75%, and 100% pigment loading.