利用锥形束CT分析宫颈癌放疗分次间摆位误差及趋势研究

A study of the inter- fraction setup errors and tendency in radiationtherapy by cone beam CT for cervix cancer

目的:利用锥形束CT(cone beam computed tomography,CBCT)获取宫颈癌调强放疗分次间摆位误差,研究变化趋势。方法:宫颈癌调强放疗22例,每位患者利用锥形束CT获取放疗前摆位误差次数6-8次,累积153次,统计放疗分次间平移及旋转摆位误差及差异,分析变化趋势。结果:分次间放疗前摆位平移误差一般不超过7mm,旋转误差一般不超过3°;平移误差Y轴最大,X轴与Z轴差异无统计学意义;旋转误差X轴最大,Y轴与Z轴差异无统计学意义。随着放疗的进行,平移及旋转摆位误差没有发现明显增加或减少的趋势。结论:宫颈癌调强放疗首次摆位Y轴平移误差及X轴旋转误差较大,随着放疗的进行未发现摆位误差增加或减少趋势。

Objective：To study the inter fraction setup errors and tendency in radiationtherapy by cone beam CT （CBCT） for cervix cancer.Methods：All 22 patients with cervix cancer were treated by IMRT,setup errors were acquired by CBCT for 6-8 times each patient before radiotherapy,a total of 153 CBCT scans.The inter-fraction setup errors and the tendency were analyed.Results：Most of the initial translational setup errors were less than 7mm,on rotational were less than 3° ;Y directions were the largest translational setup errors and no obvious differences were observed between the X and Z.X directions were the largest rotational setup errors and no obvious differences were observed between the Y and Z.With the course of radiationtherapy,no increase or decrease trend was observed in translational and rotational setup errors.Conclusion：The Y directions translational and X directions rotational setup errors were the largest;no increase or decrease trend in setup errors.was observed with the course of radiationtherapy.