2016年职称英语卫生类A级教材补全短文打印版.doc

补全短文 第十一篇Leukemia白血病 Leukemia is the most common type of cancer kids get, but it is still very rare. Leukemia involves the blood and blood-forming organs, such as the bone marrow._ Bone marrow is the innermost part of some bones where blood cells are first made._ A kid with leukemia produces lots of abnormal white blood cells in the bone marrow. Usually, white blood cells fight infection, but the white blood cells in a person with leukemia don’t work the way they’re supposed to. _ They don’t protect the person from infections very well._The abnormal white blood cells multiply out of control1, filling the bone marrow and making it hard for enough normal, infection-fighting white blood cells to form. Other blood cells — such as red blood cells (that carry oxygen in the blood to the body’s tissues) and platelets (that allow blood to clot) — are also crowded out2 by the white blood cells of leukemia. These cancer cells may also move to other parts of the body, including the bloodstream, where they continue to multiply and build up3. Although leukemia can make kids sick, most of the time it is treatable, and kids get better. Almost all leukemia patients are treated with chemotherapy, which means using anti-cancer drugs. _ The chemotherapy drugs are given through a catheter, a narrow tube that is inserted into a blood vessel, sometimes in the kid’s upper chest._Chemotherapy quickly goes to work, traveling through the blood to the bone marrow. There, the drugs can attack the cancer cells. After several weeks of chemotherapy, many kids begin to feel better. Some children with leukemia will also have to have radiation therapy, too. _ Radiation therapy uses invisible high-energy waves (similar to X-rays) to kill cancerous cells._ If the cancer isn’t getting better from using the usual amounts of chemotherapy and radiation, then kid with leukemia will probably need more treatment —with higher doses of chemotherapy and radiation to finally kill the cancer cells. But this h