The only disadvantage of the design is that at the two smallest field sizes (5 and 7.5 mm), the dose delivered per monitor unit is substantially lower than that attainable with a fixed collimator.
然而这种设计唯一的缺陷是对于2个最小的射野大小(5毫米和7.5毫米)，每个机器跳数传输的剂量基本上是低于固定准直器的。
The only disadvantage of the design is that at the two smallest field sizes (5 and 7.5 mm), the dose delivered per monitor unit is substantially lower than that attainable with a fixed collimator.
然而这种设计唯一的缺陷是对于2个最小的射野大小(5毫米和7.5毫米)，每个机器跳数传输的剂量基本上是低于固定准直器的。
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