A.<5cGy/min B.<10cGy/min C.<20cGy/min D.<30cGy/min E.<50cGy/min
A.4MV B.6MV C.8MV D.10MV E.15MV
A.1~2m B.2~2.5m C.2.5~3m D.3~4m E.5~6m