一般认为肿瘤内约有10～20%的细胞处于乏氧状态,乏氧细胞的辐射敏感性只有有氧细胞的三分之一左右,因此有碍于放疗疗效的提高。如何增加肿瘤内乏氧细胞的辐射敏感性是多年来放射治疗学家和放射生物学家所共同关注的问题。自六十年代以来,相继发现了许多能够选择性地使乏氧细胞辐射增敏的药物,统称为乏氧细胞辐射增敏剂。 It is generally believed that about 10 to 20% of the cells in the tumor are in a state of hypoxia, and the radiosensitivity of hypoxic cells is only about one-third of that of aerobic cells, which hinders the improvement of radiotherapy efficacy. How to increase the radiosensitivity of hypoxic cells in tumors has been a common concern for many years by radiation therapists and radiobiologists. Since the 1960s, a number of drugs have been discovered that selectively enable hypoxic radiation sensitization, collectively referred to as hypoxic cell radiation sensitizers.