(来学网)诊断用X射线机房的主防护铅当量厚度应是
  • A.
    (来学网)0.5mm
  • B.
    (来学网)1.0mm
  • C.
    (来学网)1.5mm
  • D.
    (来学网)2.0mm
  • E.
    (来学网)2.5mm