骨肉瘤的好发年龄是() ["A．15岁以下","B．15～25岁之间","C．20～40岁之间","D．婴幼儿","E．40岁以上"]
下列正常肺纹理的表现，哪项是错误的() ["A．上肺纹理细，下肺纹理粗","B．肺纹理呈树枝状，越分越细","C．右下肺纹理比左下肺纹理明显","D．两上肺纹理相比，右上比左上多","E．肺纹理向下伸延，可与肝影重叠"]
何谓后装短距离治疗?
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"]
骶髂关节痛的激发试验不包括() ["A．压迫试验","B．Patrick试验","C．分离试验","D．Gillet试验","E．Gaenslen试验"]
试述放射性核素的有关概念。
