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目的分析呼吸运动、摆位误差等因素对乳腺癌全乳放疗中靶区移动的影响程度。方法自2003年1月至12月,选择接受乳房保留治疗的早期乳腺癌患者,采用Med-Tec250型乳腺托架摆位固定。在模拟机透视下观察16例患者全乳治疗体积在不同方向随呼吸运动的移动幅度；利用数字化重建图像和射野验证片测量11例患者全乳切线野放疗中治疗体位在不同方向的移动幅度,计算其系统误差、随机误差和总误差,并分析其变化的时间趋势。结果射野中心肺厚度(CLD)随呼吸移动的变化幅度最大,为(2．1±1．2)mm,而全乳治疗体积的头侧、脚侧、内侧界和外侧界随呼吸移动的移动幅度较小。全乳切线野放疗中治疗体位移动的系统误差、随机误差、总误差在向后方向和向前方向及头脚方向分别为1．9、1．6、2．5mm和2．4、1．7、3．1mm及2．6、2．3、3．5mm,以头脚方向的移动误差最大；头脚方向的治疗体位移动和乳腺体积大小变化在治疗开始头2周相互间差异较大,且乳腺体积增大在照射第2周达最高峰,第3周以后则逐渐趋于稳定。结论在乳腺癌全乳切线野放疗中呼吸运动对全乳治疗体积的移动幅度平均值在2mm以内,建议提高头脚方向的固定精度。乳腺癌全乳切线野放疗中的治疗体位在治疗开始头2周变异较为明显,照射引起的乳腺水肿在第2周达到最高峰。
Objective To analyze the influence of respiratory movement, setting error and other factors on the movement of target in breast milk during whole milk radiotherapy. Methods From January to December 2003, patients with early stage breast cancer who underwent breast preservation were selected and placed on Med-Tec 250 breast brackets. In the perspective of simulator, the movement range of whole milk volume in different directions with respiratory motion was observed in 16 patients. The movement range of body position in different directions was measured with digitized reconstruction images and field verification tablets in 11 patients , Calculate its systematic error, random error and total error, and analyze its changing trend of time. Results The lung volume (CLD) in the center of the radioactivity ranged from (2.1 ± 1.2) mm with the largest change in respiration, while the movement of the head, foot, medial and lateral lobes of the whole milk volume with respiratory movement Slightly smaller. System error, random error, total error in total tangent line field radiotherapy in the treatment of position movement, the total error in the backward and forward directions and head and foot direction were 1.9,1.6,2.5mm and 2.4,1. 7,3.1mm and 2.6,2.3,3.5mm, the movement of the head to the foot of the largest error; head and foot direction of the treatment position and the size of the breast changes in the first two weeks of treatment between the larger differences between each other , And the mammary gland enlargement reached its peak at the second week of irradiation and gradually stabilized after the third week. Conclusions The average moving amplitude of respiration rate in the treatment of whole breast with the whole-breast tangent radionuclide radiation is within 2mm, so it is suggested to improve the fixation accuracy in the direction of head and foot. Breast cancer tangential line field radiotherapy in the treatment of position in the first 2 weeks of treatment variation is more obvious, radiation-induced breast edema reached the peak in the first 2 weeks.