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新托福阅读材料:Proton Therapy
Doctors have developed a promising new procedure that could (1)revolutionize the way we fight cancer. Learn about proton therapy on this Moment of Science.
If you or someone you know has had cancer, then you know how frightening and painful treatment can be. But during the past few decades doctors have developed a promising new procedure called proton therapy that could revolutionize the way we fight cancer.
Proton therapy is basically a new kind of radiation treatment. Until recently, all radiation therapy used X-Rays. X-Rays are good at destroying cancer cells, but the problem is that when they pass through the body, they attack not only cancer cells but also surrounding healthy cells. So doctors have been forced to use radiation doses low enough to minimize damage to non-cancerous cells.
Proton therapy is a more accurate way of attacking cancer with radiation. Unlike X-Rays, which go through a patient and out the other side, protons penetrate only to the desired point and then stop. So cells deeper in the body than where the tumor is are not affected.
Protons also release most of their destructive energy just before they stop, so healthy cells in front of the tumor get less radiation than the cancer cells do. Proton therapy’s accuracy means that doctors can train high doses of proton radiation on (2)tumors without worrying about causing (3)collateral damage.
Proton radiation is not a miracle cure–in fact, it’s limited to treating (4)localized cancers that have not spread throughout the body. Still, it’s an important new tool for battling a deadly disease, especially for tumors deep inside the head or neck, where doing surgery would be too risky. |
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