What is injury produced by ionizing radiation?

Ionizing radiation removes tightly bound electrons causing collisions of free electrons w/other atoms. Cause DNA damage and carcinogenesis (not precisely repaired damage, leads to mutations can manifest in years as cancer) On organ systems DNA damage leads to rapid division of germ cells, in bone marrow and GI very sensitive to radiation injury, cause neoplastic transformation since not repaired and may cause vascular damage and sclerosis causing ischemic necrosis of parenchymal cells and replacement by fibrous tissues. We see fibrosis (by radiotherapy in irradiated field, weeks or months after irradiation). We get wide range of changes in chromosomes, mitotic spindle cause polyploidy/aneuploidy, we see apoptosis, abnormal nuclear cells for years giant cells/ pleomorphic nuclei. In hemato may see marrow aplasia.