[问答题,简答题] 术前放疗有何意义?

肩关节周围炎的治疗，首选() ["A．石膏固定","B．伤湿止痛膏药外用","C．运动+光热等物理治疗","D．关节内注射醋酸泼尼松龙","E．手术"] 术后放疗有何意义? 下列哪项在肺纹理的构成中不是主要构成部分() ["A．肺动脉分支","B．支气管","C．淋巴管","D．间质组织","E．肺静脉"] 右主支气管与气管中线成多少度角() ["A．10～20°","B．20～30°","C．30～40°","D．40～55°","E．50～60°"] 何谓姑息性放疗? 术前放疗有何意义?