不同体位固定方式在乳腺癌放疗中的应用

Application of different posture fixation methods in radiotherapy of breast cancer

目的:研究真空垫(VP)、真空垫联合乳腺托架(VB)和发泡胶联合乳腺托架(PB)对乳腺癌放疗中分次间摆位误差、分次内患者移动及剂量学的影响。方法:前瞻性收集2019-2021年在江苏省肿瘤医院接受放射治疗乳腺癌患者共96例,按简单随机法分为VP组、VB组和PB组,每组32例。利用锥形束CT(CBCT)和计划系统获取患者分次间摆位误差和分次内移动及剂量学分布,以及患者锁骨上区域摆位误差和真空垫、发泡胶形变数据。结果:3组固定方式分次间摆位误差在左右(LR)方向差异无统计学意义(P>0.05),头脚(SI)方向上PB组小于VB组(3.02±2.04、3.65±2.64,t=2.35,P=0.031),腹背(AP)方向上VB与PB组均优于VP组(3.36±2.93、3.14±0.98、4.03±2.55,t=2.29、3.11,P<0.05)。分次内移动仅AP方向上VP组与PB组优于VB组(1.31±0.95、1.24±0.89、1.88±1.33,t=-2.04、-2.31,P<0.05);分次内移动对剂量学分布无影响(P>0.05);乳腺托架未能改善锁骨上区域摆位重复性(P>0.05);测量点中发泡胶塑形稳定性均优于真空垫(t=2.43~5.63,P<0.05)。结论:使用PB固定方式能减少乳腺癌患者分次间摆位误差和患者分次内移动;发泡胶在患者整个治疗过程中能保持塑形的稳定性。

Objective To study the inter-fraction setup errors,intra-fraction movement of patients and its influence on dosimetry,position repeatability of the supraclavicular area,and the plastic stability of the vacuum cushion and styrofoam when one of the three fixation method are applied in the clinical radiotherapy of breast cancer.The three fixation method include acuum negative pressure pad(VP),acuum negative pressure pad combined with a breast bracket(VB),and polyurethane styrofoam combined with a breast bracket(PB).Methods A total of 96 breast cancer patients who received radiotherapy at Jiangsu Cancer Hospital during 2019-2021 were collected prospectively for study.They were randomly divided into three groups(VP,VB,and PB).Cone-Beam CT and a planning system were used to obtain inter-fraction setup errors,intra-fraction movement of patients and its influence on dosimetry,position repeatability of supraclavicular area,and the plastic stability of vacuum pad and polyurethane tyrofoam.Results In the left-right(LR)direction,there were no statistical differences in the inter-fraction setup errors among the three groups.In the superior-inferior(SI)direction,inter-fraction setup errors of the PB group were smaller than those of the VB group(3.02±2.04,3.65±2.64,t=2.35,P=0.031).In the anterior-posterior(AP)direction,the inter-fraction setup errors of both the VB and PB groups were smaller than those of the VP group(3.36±2.93,3.14±0.98,4.03±2.55,t=2.29,3.11,P<0.05).In the AP direction,the intra-fraction movement of patients of the VP and PB groups were less than that of the VB group(1.31±0.95,1.24±0.89,1.88±1.33,t=-2.04,-2.31,P<0.05).Moreover,the intra-fraction movement of patients had no statistical effect on the dosimetric distribution(P>0.05),and the breast bracket did not improve the position repeatability of the supraclavicular region(P>0.05).In addition,the plastic stability of polyurethane styrofoam was significantly better than that of the acuum negative pressure pad(t=2.43-5.63,P<0.05).Conclusions The inter-fraction setup errors and intra-fraction movement of patients with breast cancer can be reduced by using PB.Compared to an acuum negative pressure pad,polyurethane styrofoam can keep plastic stability throughout the treatment of the patients.