题型:单项选择题 关于核医学放射性核素的选择,下列说法错误的是:()A.诊断性用药的放射性核素要有比较短的半衰期B.为减少电离辐射对人体的危害,显像常用的核素γ射线能量小于100 keV为好C.治疗性用药目前多应用以发射β射线为主的核素D.发射α射线类核素、俄歇电子类核素也可以用于核素治疗E.治疗性用药的放射性核素要有比较长的半衰期 查看答案
题型:单项选择题 Even though I have been to her apartment several times before, I still don’t remember ()。A. which building it is inB. which the building is inC. which is it inD. which building is it in 查看答案