乳腺癌单托架和双托架体位固定技术在IMRT临床应用中的综合评价

Comprehensive evaluation of single-bar and double-bar setup in radiotherapy for breast cancer

目的:探讨对于乳腺切除术后的乳腺癌患者行调强放射治疗时体位固定技术的选择。方法:回顾性分析2017年03月至2018年11月104例接受乳腺切除术后IMRT的乳腺癌患者,所有患者均采用Klarity公司生产的碳纤维乳腺托架,并且随机采用单托架和双托架方式固定患者体位。然后由医生勾画靶区,物理师设计IMRT计划。评估PTV的V55、Dmin、Dmax、Dmean、CI和HI,评估危及器官剂量(包括全脊髓的Dmax;同侧肺V5、V20和Dmean;对侧肺V5和Dmean;全肺的V5、V20和Dmean以及心脏的V5、V10、V20、V30和Dmean);根据影像验证结果评估三个坐标方向的摆位误差并比较摆位花费的时间。结果:两组患者中平均年龄、体质量指数和病变部位P值分别为0.860、0.103和0.812,两组患者特征具有可比性。单托架和双托架固定技术具有相同的PTV的剂量分布(V55、Dmin、Dmax、Dmean、CI和HI的P>0.05)。单托架固定技术的心脏V20和V30分别为(6.16±5.43)%和(3.87±2.76)%;双托架固定技术的心脏V20和V30分别为(11.52±6.01)%和(6.75±4.12)%;单托架固定技术的心脏V20和V30低于双托架固定技术(P<0.05)。单托架固定技术摆位误差在左右(X)方向上低于双托架固定技术(0.03±0.12,0.07±0.17,P=0.047)。结论:两种固定技术都能够满足临床乳腺癌放射治疗的要求,与双托架固定技术相比,单托架固定技术可以降低心脏辐射剂量的同时降低部分摆位误差。对于更严格的剂量对比,需要进一步的研究来证明。

Objective:To explore which setup technique is more suitable for intensity modulated radiation therapy for breast cancer patients after mastectomy.Methods:104 breast cancer patients with IMRT after mastectomy from March 2017 to November 2018 were retrospectively analysed,and all were treated with carbon fiber breast bracket manufactured by Klarity,and were randomly assigned to either unilateral or bilateralbracket.Then the physician uutlined the target area and the physical engineer designed the IMRT program.V55,Dmin,Dmax,Dmean,CI and HI of PTV were evaluated.Ipsilateral lung V5,V20 and Dmean,V5 and Dmean in contralateral lung,V5,V20 and Dmean in the whole lung and V5,V10,V20,V30 and Dmean in the heart were evaluated.According to the image verification results,the positioning errors of the three coordinate directions wre evaluated and the time taken for positioning was compared.Results:The P values of The mean age,body mass index and lesion values in the two groups were 0.860,0.103 and 0.812,respectively.The characteristics of the two groups were comparable.The unilateral bracket and bilateral bracket positioning technology had the same dose distribution of PTV(P>0.05 of V55,Dmin,Dmax,Dmean,CI and HI).The cardiac V20 and V30 of single bracket positioning technology were(6.16±5.43)%and(3.87±2.76)%,respectively.The cardiac V20 and V30 of double bracket positioning technology were(11.52±6.01)%and(6.75±4.12)%,respectively.The cardiac V20 and V30 of single bracket positioning technology were lower than that of double bracket positioning technology(P<0.05).The positioning error of unilateral bracket positioning technique was lower than that of bilateral bracket positioning technique in the left and right(X)direction(0.03±0.12 vs 0.07±0.17,P=0.047).Conclusion:Both of the two positioning techniques can meet the requirements of clinical breast cancer IMRT.Compared with the two-bar positioning technique,the unilateral bracket positioning technique can reduce the radiation dose of the heart and at the same time reduce some positioning errors.More rigorous dose comparisons are needed to demonstrate this.