(来学网)直线加速器为基础的X线SRT使用的射野大小为
  • A.
    (来学网)直径≤50mm
  • B.
    (来学网)直径=50mm
  • C.
    (来学网)直径≥50mm
  • D.
    (来学网)直径≤18mm
  • E.
    (来学网)直径≥18mm