In our previous episode, we explored the acute, or early, effects of radiation on rapidly dividing normal tissues like the skin, gut, and bone marrow. These effects, while often distressing, are typically transient and heal. Today, we shift our attention to a different category of radiation injury: late effects. These complications can manifest months or even years after the completion of radiotherapy and are often progressive and irreversible, posing significant long-term challenges for our patients. We'll specifically delve into the late effects on two critical organ systems: the central nervous system (CNS) – including the brain and spinal cord – and the lungs.