Definition of Radiation fibrosis

Radiation fibrosis: Scarring of the lungs from radiation. Radiation fibrosis is a consequence of the repair process that follows radiation pneumonitis (inflammation of the lungs due to radiation), as from radiation therapy. Radiation fibrosis typically occurs within months to a few years after the completion of radiation treatments. Whereas the inflammation of radiation pneumonitis is often reversible with medications, radiation fibrosis is usually irreversible and permanent.