colon หรือ large intestine is a tube lined with muscles that extracts moisture and nutrients from
food, storing the waste matter until it is expelled from the body. It is typically 5 to 6 feet long in
adults. The last segment of the colon is called the rectum.
Radiation colitis occurs when an increasing number of cells in
the colon die as a result of radiation therapy. Often the doses
of radiation that cause colon injury are very close to the doses
needed to treat cancer in the abdomen or pelvis. The severity
of the condition depends on the size of the radiation dose
and other factors such as the frequency of treatment and
tumor size.