High doses of X-rays and other kinds of ionizing radiation can damage the DNA present in the cell nucleus, a phenomenon which can both lead to the development of cancer in humans and be used to kill cancer cells. This damage to DNA occurs through two mechanisms: one involves the direct physical impact of ionizing particles; the other is indirect, involving an attack on nucleic acids by chemical species arising from water radiolysis (the decomposition of hydrogen bonds between H2O molecules).
