The proposition for the use of hyperbaric oxygen or "hybaroxia" in the radiation therapy of cancer stands firmly on its foundation in radiation chemistry, radiation physics, and radiation biology. The electromagnetic energy generated in an x-ray machine or derived from nuclear disintegration of isotopes produces ions on impact with substances of atomic structure. The ions are the result of energy disruptions of the electron orbits of the atom, of which the biologic target is made. By the subtraction of an electron in one place and the addition in another, ionizations and free radicals are produced. Such events allow for the disturbance of the normal equilibrium of the chemical substrate making up the biologic material. From radiophysics and chemistry, a simplified explanation of the oxygen effect on ion production may be found in water studies—a relevant consideration in that biologic tissues have been referred to as an aquarium of living molecules.
Wildermuth O. The Case for Hyperbaric Oxygen Radiotherapy. JAMA. 1965;191(12):986-990. doi:10.1001/jama.1965.03080120020006