早期乳腺癌保乳术后应用记忆热塑网膜固定方式在螺旋断层放射治疗中摆位误差分析

Set-up errors of memory thermoplastic fixation in postoperative helical tomotherapy radiotherapy for early breast conserving surgery

目的探讨在早期乳腺癌患者保乳术后行螺旋断层放射治疗,应用记忆热塑网膜固定方式的摆位误差。方法回顾性分析沈阳军区总医院放疗科自2015年8月至2017年8月收治16例乳腺癌术后接受放疗患者的临床资料。所有患者均为早期乳腺行保乳术后,接受螺旋断层放射治疗。放疗前,所有患者均应用记忆热塑网膜定位,且每次治疗前均行MVCT图像扫描;并与定位CT图像融合配准,记录左右(X)、头脚(Y)、腹背(Z)及横断面方向旋转(Roll)的误差值,对所有16例患者400次配准数据进行统计分析。结果本组16例早期乳腺癌保乳术后患者,治疗前共行400次扫描,X、Y、Z及Roll方向的摆位误差分别为(3.102±1.864)mm、(3.342±2.088)mm、(2.133±1.739)mm及(1.047°±0.790°)。X、Y及Z方向上的摆位误差≤5 mm的比例分别为85.00%(340/400)、78.75%(315/400)和92.00%(368/400),Roll方向旋转误差≤2°的比例为88.00%(352/400)。结论早期乳腺癌患者行保乳术后接受螺旋断层放射治疗,应用记忆热塑网膜固定方式的摆位误差小,可提高放疗的精确性,有利于保证靶区剂量及控制正常组织受量,可应用于临床精确放疗中。

Objective To investigate the Set-up errors of memory thermoplastic fixation in postoperative helical tomotherapy （HT）for early breast cancer patients who underwent breast conserving surgery. Methods A retrospective study was per-formed on 16 cases of patients who underwent radiotherapy after breast cancer surgery from August 2015 to August 2017. All the patients underwent early breast conserving surgery,then were given HT. Before the radiothempy,all the patients were given memory thermoplastic fixation,and were scanned by MVCT each time before treatment;MVCT was performed image fusion registration with CT positioning image. The error values of the rotation of left-right（X）, head-foot（Y）, abdominal- back（Z）and cross-sectional direction（Roll）were recorded,and 400 registration data of all 16 patients were statistically ana-lyzed. Results All 16 cases were given 400 times of scanning before treatment,the set-up error of X, Y , Z and Roll was （3. 102 ±1. 864）mm,（ 3. 342 ±2. 088）mm and（2. 133 ± 1. 739）mm and（1. 047° ±0. 790° ） . The set-up errors of X,Y and Z was less than 5 mm,and the ratio was 85. 00% （340/400）, 78. 75% （315/400） and 92. 00% （368 /400 ）, respective- ly;the ratio of Roll direction error was less than 2° , 88. 0 0% （3 5 2 /4 0 0 ） . Conclusion The memory thermoplastic fixation in postoperative helical tomotherapy for early breast cancer patients who underwent breast conserving surgery has the advan-tages such as slight set-up errors, higher accuracy of radiotherapy, controlled dose of target location and normal tissues, which is worth of clinical promotion.