肿瘤放疗中塑形垫结合热塑网膜体位固定方式的摆位误差研究

目的:探究塑形垫结合热塑网膜体位固定方法在放疗过程中较单一热塑网膜或真空垫固定方法能否减少摆位误差。方法:分析2018年1月至2019年12月于湘雅常德医院接受放疗的头颈和胸腹肿瘤患者66例,其中头颈肿瘤患者27例、胸腹肿瘤患者39例。15例头颈肿瘤患者使用头颈肩热塑面罩固定(A组),12例使用塑形垫结合头颈肩热塑面罩固定(B组);19例胸腹肿瘤患者使用真空垫固定(A组),20例使用塑形垫结合热塑体膜固定(B组)。对所有患者实施锥形束CT扫描,统计配准后得到左右(left-right,LR)、头脚(superior-inferior,SI)和腹背(anterior-posterior,AP)方向及旋转角度摆位误差值,分析不同体位固定方式间的摆位误差大小。结果:对于头颈肿瘤患者,B组在LR、SI以及旋转角度误差分别为(0.06±0.06)cm、(0.08±0.07)cm、(0.12±0.17)°,小于A组的摆位误差(0.10±0.11)cm、(0.13±0.14)cm、(0.25±0.47)°,差异具有统计学意义(P<0.05),AP摆位误差差异无统计学意义(P>0.05);对于胸腹部肿瘤患者,B组在LR和旋转角度误差分别为(0.10±0.08)cm、(0.09±0.18)°,小于A组摆位误差(0.14±0.12)cm、(0.22±0.39)°,差异具有统计学意义(P<0.05),在SI和AP摆位误差差异无统计学意义(P>0.05)。结论:在头颈肿瘤和胸腹肿瘤患者放疗过程中使用塑形垫结合热塑网膜的体位固定方式相比于其他单一体位固定方式而言,能够提升患者体位的重复性、稳定性,减少摆位误差。

Analysis of setup errors in patients using the customized Klarity AccuCushion■with a thermoplastic fixation mask while receiving radiotherapy

Objective:To compare setup errors between patients using the customized Klarity AccuCushion■ with a thermoplastic fixation mask and patients using a thermoplastic fixation mask or vacuum fixation cushion alone while receiving radiotherapy.Methods:A total of 66 patients with head and neck(H&N)tumors(n=27)or thoracic and abdominal tumors(T&N)tumors(n=39)were included during Jaurnary 2018 to December 2019.15 H&N cancer patients using only a single head-neck-shoulder mask were categorized into group A;12 patients using a customized Klarity AccuCushion■ and head-neck-shoulder mask were categorized into group B.Among T&A cancer patients,19 patients using only a vacuum fixation cushion were classified into group A;the remaining 20 patients using a customized Klarity AccuCushion■ and thermoplastic fixation mask were classified into group B.Cone-beam computed tomography was performed,and the setup errors were evaluated.The setup errors in the left-right(LR)direction,superior-inferior(SI)direction,anterior-posterior(AP)direction,and for rotation were compared between groups A and B.Results:Among H&N cancer patients,the setup errors in group B in the LR direction,SI direction,and for rotation were 0.06±0.06 cm,0.08±0.07 cm,and 0.12±0.17°,respectively,which were smaller than those in group A(0.10±0.11 cm,0.13±0.14 cm,and 0.25±0.47°,respectively).The differences in setup errors in the LR direction,SI direction,and for rotation were significant between the two groups(P<0.05),while no significant difference was found in setup errors in the AP direction(P>0.05).For T&A cancer patients,significant differences were found in setup errors between the two groups(P<0.05)in the LR direction(group B vs.group A:0.10±0.08 cm vs.0.14±0.12 cm)and for rotation(group B vs.group A:0.09±0.18°vs.0.22±0.39°).No significant differences were observed in the setup errors in the SI and AP directions.Conclusions:Compared with the immobilization techniques using only a thermoplastic mask and only a vacuumed fixation cushion,the technique using a customized Klarity AccuCushion■ with a thermoplastic fixation mask can improve repeatability,stability,and setup errors in radiotherapy.