影响乳腺癌术后精确放疗的因素分析

背景与目的:乳腺癌精确放疗的实施有赖于定位、计划及治疗实施等多个步骤的协作完成.本研究探讨乳腺癌切线野放射治疗实施过程中摆位误差对精确治疗的影响.方法:共入组50例改良根治术后或保留乳房术后乳腺癌患者,放疗靶区主要为患侧胸壁和(或)乳腺.放射治疗技术以切线野等中心治疗为原则,在此基础上针对不同患者选择采用半野照射或MLC多叶光栅照射技术.患者治疗时仰卧于MED-TEC250型乳腺托架,治疗设备为Eleckta Precise加速器.在患者每次治疗过程中在摆位完毕后,按内切野治疗前-内切野治疗后-外切野治疗后顺序分别记录加速器所显示X、Y、Z读数,X代表左右方向的移动度,Y代表头脚方向的移动度,Z代表腹背方向的移动度.结果:最大的平均位移差值为第1周,在Z轴、Y轴、X轴方向分别为2.55、3.96、0.58 cm.3个方向中,随时间推移Z轴方向移动最大.从其他影响因素考虑,发现上肢活动情况及托架位置对患者治疗的移动变化影响大. 结论:在乳腺癌患者切线野放射治疗中,内切野治疗后患者的移动度较外切野治疗后大;从不同轴向而言,X方向(左右方向)移动明显小于Y方向(头脚方向)和Z方向(腹背方向);从整个疗程而言,前2周中患者的移动度较大,而从第3周起,患者移动度变小并且趋于稳定.

Impact of treatment set-up errors on accuracy of post-operation radiotherapy in patients with breast cancer

Background and purpose: The precise radiotherapy in patients with breast cancer consists of multiple procedures, such as simulation, treatment planning and delivery. We assessed the impact of treatment set-up errors on accuracy of post-operative radiotherapy (RT) in patients with breast cancer receiving tangential RT. Methods: Between November 2007 and August 2008, a total of 50 patients were enrolled an institutional review board-approved study. All patients received tangential RT for either right or left breast cancer. Read-out numbers of X, Y, Z directions shown on linear accelerator were recorded according to the sequence of before and after medial tangential field and after lateral tangential field.The impact of treatment set-up errors on post-operative radiotherapy (RT) in different subgroup patients was analyzed using stata 7.0 statistics software. Results:The mean set-up errors on Z, Y, X direction were 2.55, 3.96 and 0.58 cm, respectively. The largest set-up errors in all three directions were observed in the first week during treatment and the largest movement was observed in Z direction. Conclusion: The movements after medial tangential field treatment are much more than those after lateral treatment during RT.The movements in X direction arc substantially less than Y direction or Z direction intrafraction. As interfraction differences have been observed, the movements in the beginning two weeks are more than other treatment period.