硅胶产生的空腔对乳腺癌根治术后调强放射治疗的剂量学影响  

Dosimetric effects of bolus-generated air cavities in the breast on intensity-modulated radiation therapy after radical mastectomy

作　　者：刘婷婷[1] 刘锐锋[1] 欧阳水根[1] 魏玺仪[1] 刘志强[1] 张明[1] 陶娜[1] 牛瑞军 郭晴 陶发利 杨文翠[1] LIU Tingting;LIU Ruifeng;OUYANG Shuigen;WEI Xiyi;LIU Zhiqiang;ZHANG Ming;TAO Na;NIU Ruijun;GUO Qing;TAO Fali;YANG Wencui(Department of Radiotherapy,Gansu Provincial Cancer Hospital,Lanzhou 730000,China)

机构地区：[1]甘肃省肿瘤医院放疗科,兰州730000

出　　处：《辐射研究与辐射工艺学报》2020年第3期39-45,共7页Journal of Radiation Research and Radiation Processing

基　　金：甘肃省卫生行业科研计划项目(GSWSKY-2015-27);兰州市人才创新创业项目(2017-RC-23)资助。

摘　　要：为提高硅胶填充物(Bolus)使用的可靠性,对比4种不同厚度Bolus设置方式产生的空腔大小对乳腺癌根治术后调强放疗的剂量学影响。根据空腔大小范围制定3套适形调强放射治疗(Intensity-modulated radiation therapy,IMRT)计划方案Plan1(空腔大于10 mm)、Plan2(空腔大于5 mm且小于10 mm)、Plan3(空腔小于2 mm),并与常规计划设计下Bolus服帖在皮肤上无空腔的IMRT(Plan4)进行剂量对比,分析剂量–体积直方图(DVH)与三维剂量分布图,采用统计软件包(SPSS)对数据进行统计分析,评价靶区和危及器官的剂量分布差异。统计分析得知,4种方案所有靶区剂量学指标均满足处方剂量要求,且无统计学差异(p>0.05);但剂量分布图显示,Plan1与Plan2空腔附近靶区聚集不等范围的高剂量区及近皮肤剂量不足区,Plan1程度较Plan2大;DVH结果显示,Plan3与Plan4能够更好降低食管平均剂量Dmean、气管平均剂量Dmean、患侧肺接受≥30 Gy照射的体积百分比V30,以及辅助结构Ring接受≥40 Gy、45 Gy照射体积百分比V40、V45,且差异均有统计学差异(p<0.05)。对比得知,小空腔(小于2 mm)能够减少靶区内的冷点与热点,降低危及器官受量,更接近理想计划方案。Plan3采用2 mm叠加3 mm的方式,将大空腔缩小至2 mm以下,既能满足Bolus的补偿作用,又能避免Bolus物理特性引起的剂量学误差,保证治疗质量。To improve bolus reliability,we compared three different cavity sizes generated by different bolus thicknesses in patients by introducing intensity-modulated radiation therapy(IMRT)after radical mastectomy and analyzed the differences in dosimetry.Three IMRT plans—1,2,and 3—were designed for cavity sizes greater than 10 mm,greater than 5 mm and less than 10 mm,and less than 2 mm,respectively.All three plans were compared to Plan 4(bolus clinging to the skin),which was conventionally used as a standard benchmark case.The present study analyzed the dose-volume histogram(DVH)and three-dimensional dose distribution profiles.The differences in dose distributions between the target area and the organ at risk were evaluated by statistical analysis on statistical package of social sciences(SPSS).The dose parameters of all the four plans satisfied the prescription dose requirements and no statistically significant differences were observed(p<0.05).However,the dose distribution map showed that the target areas in the cavities had high concentration areas and cold areas nearby the skin for both Plans 1 and 2.The DVH results showed reduced mean dose(Dmean)to the esophagus and trachea,percent volume received by the affected lung(V30≥30 Gy),and percent volume received of the auxiliary structure ring(V40≥40 Gy and V45≥45 Gy)for Plans 3 and 4.The differences were statistically significant(p<0.05).Comparisons showed that Plan 3 reduced hot and cold spots around the target area,therefore reducing the risk of organ damage and indicating that it was the best plan in the present study.Plan 3 used a superposition method from 2 mm to 3 mm,which reduced the cavity size to less than 2 mm.It satisfies the compensation function of the bolus and avoids dosimetry error caused by the physical characteristics of the bolus,thus improving treatment quality.

关 键 词：硅胶 空腔 乳腺癌 调强放射治疗 剂量学 

分 类 号：TL72[核科学技术—辐射防护及环境保护]