[问答题,简答题] 透视和摄片各有何优点和缺点?

何谓医学影像学? 真皮中含量最丰富的纤维成分是() ["A．胶原纤维","B．网状纤维","C．弹力纤维","D．弹性纤维"] 浅述正常乳腺导管造影的X线征象? 骨骼基本病变的X线表现有哪些? 区别真性延髓麻痹和假性延髓麻痹的最可靠体征为() ["A．是否双侧受累","B．舌能否伸","C．有无声嘶","D．有无吞咽困难","E．有无舌肌萎缩"] 透视和摄片各有何优点和缺点?