乳腺癌全乳切线野照射中靶区移动影响因素的研究  

Factors influencing target volume motion in tangential whole breast irradiation for breast cancer

作　　者：黄晓波[1] 陈佳艺[1] 蒋国樑[1] 许青[1] 陆惠忠[1] 龚建舟[1] 

机构地区：[1]复旦大学附属肿瘤医院放疗科

出　　处：《中华放射肿瘤学杂志》2006年第6期453-456,共4页Chinese Journal of Radiation Oncology

摘　　要：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 evaluate the impact of breathing motion on target volume and the factors influencing the set-up errors during tangential whole breast irradiation. Methods From Jan 2003 to Dec 7003, patients with early-stage breast cancer after breast conserving surgery, were selected to be eligible for the study. All patients were immobilized in treatment position by breast board of Med-Tec 250. The motion of the breast treatment volume was observed on a fluoroscope in different directions under free breathing in 16 patients. The set-up errors in different dimensions during irradiation were measured by weekly portal films （PF） in comparison with digital reconstructed radiographs （DRR） in l l patients. Results The central lung distance （CLD） variation during free breathing was （ 2.1 ± 1.2 ） mm which is greater than the motion towards the other directions. By comparing the PF and DRR, the systemic error, random error and overall error in the outer, inner and cranio-caudal directions was 1.9, 1.6, 2.5 and 2.4, 1.7, 3.1 and 2.6, 2.3, 3.5 mm, respectively. In addition, the discrepancy of the treatment position in cranio-caudal direction and breast volume was most obvious at the beginning 2 weeks with the peak of breast volume at the second week. It decreased gradually during the following 3 weeks. Conclusions This study suggests that the mean value of the motion of the breast target volume during one breathing cycle is less than 2 mm. The set-up errors during irradiation is the greatest in cranio-caudal direction, suggesting that the fixing precision of the breast board should be further improved. The set-up error during irradiation are most obvious at the beginning two weeks, with the peak of the breast volume in the second week.

关 键 词：乳腺肿瘤/放射疗法 调强放疗 靶体积 摆位误差 

分 类 号：R737.9[医药卫生—肿瘤]