目的：对比研究锥形束CT(cone-beam computed tomography，CBCT)转化头颅侧位片与传统X线 头颅侧位片定点的一致性。方法：53名(男24名，女29名)正畸患者治疗前拍摄头颅侧位片和锥形 束CT扫描。选取22个常用标记点，由同一操作者对所有侧位片进行定点，间隔进行三次。采用 Hotelling T2检验两种类型头颅侧位片定点的一致性。结果：绝大多数的定点差异无统计学意义。 有4个点，耳点(t=0.50，P=0.006)、前鼻棘点(t=0.49，P=0.008)、下颌角点(t=0.39，P=0.039)和颅 底点(t=0.64，P=0.006)，定点差异有统计学意义(P<0.05)。结论：锥形束CT转化的头颅侧位片定 点更加精确，可以代替传统的X线头颅侧位片。
Landmark accuracy on CBCT-generated cephalograms and conventional lateral cephalograms
Objective: To investigate systematic differences in landmark position between conventional lateral cephalograms and cone-beam computed tomography (CBCT)-generated cephalograms. Methods: Subjects were 53 patients (24 males and 29 females). All patients were imaged using CBCT and conventional lateral cephalograms. Cephalograms were verified and 22 landmarks were identificated 3 times by one operator. Hotelling T2 was used to analyze variability differences. Results: There were no systematic differences between modalities in the position of most landmarks. Four landmarks, porion (t=0.50, P=0.006), anterior nasal spine (t=0.49, P=0.008), gonion (t=0.39, P=0.039), and basion (t=0.64, P=0.006), showed statistically significant differences. Conclusion: CBCT-generated cephalograms provide more precise identification and can successfully replace conventional cephalograms.