试述放射性核素的有关概念。
非骨化纤维瘤的好发部位是() ["A.胫骨近端及股骨远端","B.胫骨远端及股骨近端","C.肱骨近端","D.颅顶骨","E.脊柱骨"]
X线管阳极靶面材料的特点不包括下列哪项 ( ) ["A.原子序数高","B.X线发生效率高","C.熔点高","D.焦点小","E.金属蒸发率低"]
影响射线的物理条件有哪些?
L椎间盘突出时可能出现的肌力改变是() ["A.伸膝无力","B.趾背伸无力","C.足跖屈无力","D.肛门括约肌无力","E.膀胱括约肌无力"]
试述照射量和吸收剂量的概念。