来自《耶鲁大学开放课程：生物医学工程探索 第24集 第24集》

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  You have repair mechanisms,
  你具有修复机制
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  either by producing new cells
  或者产生新的细胞
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  or by repairing the DNA that gets damaged in cells,
  或者修复细胞中受到损伤的DNA
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  you can recover from the damage that happens.
  你能够从损伤中得到恢复
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  But if radiation continues to be delivered to that tissue,
  但如果组织受到持续的放射
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  you can overwhelm the body's ability to repair itself.
  那么就会超过身体修复自己的能力
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  You can actually cause sections of tissues
  这确实能够导致
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  or cells within sections of tissues to die,
  组织或者细胞部分的死亡
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  and that's the basis for radiation therapy.
  这就是放疗的基础
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  This graph which is--which describes an experiment
  这张图片描述了一个
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  that was done many decades ago,
  数十年前进行的实验
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  shows how radiation can be used to kill cells.
  它展示了辐射是怎么样杀死细胞的