基于RGSC系统的左乳腺癌深吸气屏气放疗的应用及评估

Application and evaluation of DIBH radiotherapy using RGSC for left-sided breast cancer

目的:分析心脏和肺的受照剂量、治疗时间和摆位精度评估呼吸门控扫描器系统(RGSC)引导实现左乳腺癌术后深吸气屏气(DIBH)放疗的临床价值。方法:分别选择20例使用RGSC实现左乳腺癌术后DIBH容积调强弧形放疗的病例和20例左乳腺癌术后自由呼吸(FB)放疗的病例,两组病例的靶区都仅包含胸壁区和锁骨区。获取心脏V_(20)、D_(mean)和肺V_(20)、V_(10)、V_(5)、D_(mean);分析靶区配准结果,记录每次治疗时间。结果:DIBH和FB放疗的心脏V_(20)分别是2.36%±2.16%、7.26%±3.66%(P<0.01),心脏D_(mean)分别是(3.52±1.10)Gy、(6.56±1.59)Gy(P<0.01)。左肺V_(20)、V_(10)、V_(5)、D_(mean)分别是18.56%±4.51%vs 23.51%±4.37%(P=0.03)、30.48%±4.99%vs 37.99%±5.13%(P<0.01)、45.95%±5.81%vs 52.08%±12.74%(P=0.02)、(10.57±1.86)Gy vs(12.43±1.66)Gy(P=0.01);右肺V_(5)、D_(mean)分别是7.82%±3.59%vs 18.41%±11.44%(P<0.01)、(1.97±0.36)Gy vs(3.08±1.12)Gy(P<0.01)。DIBH和FB放疗的治疗时间为181.00(151.00,229.00)s,70.2(69.60,70.20)s(P<0.01)。CBCT图像进行6维配准后,在X、Y、Z平移方向和Rx、Rz旋转方向,DIBH放疗的配准误差小于FB放疗,在Ry方向差异没有统计学意义(P>0.05)。结论:基于RGSC系统实施左乳腺癌术后DIBH放疗可以实现较好的治疗精度,降低肺和心脏的剂量,但明显增加治疗时间。

Objective To evaluate the clinical value of RGSC-guided deep inspiration breath hold(DIBH)radiotherapy following surgery for left-sided breast cancer by analyzing the exposure doses to heart and lung,treatment duration,and positioning accuracy.Methods After surgery for left-sided breast cancer,20 cases receiving RGSC-guided DIBH volumetric modulated arc therapy and 20 cases treated with FB radiotherapy were enrolled,and the target areas contained only the chest wall and the clavicle.The V_(20),D_(mean)of the heart,and the V_(20),V_(10),V_(5),D_(mean)of the lung were obtained;the target registration results were analyzed;and the duration of each treatment was recorded.Results The V_(20)and D_(mean)of the heart in DIBH radiotherapy and FB radiotherapy were 2.36%±2.16%vs 7.26%±3.66%(P<0.01),and(3.52±1.10)Gy vs(6.56±1.59)Gy(P<0.01).The V_(20),V_(10),V_(5)and D_(mean)of the left lung in the two groups were 18.56%±4.51%vs 23.51%±4.37%(P=0.03),30.48%±4.99%vs 37.99%±5.13%(P<0.01),45.95%±5.81%vs 52.08%±12.74%(P=0.02),(10.57±1.86)Gy vs(12.43±1.66)Gy(P=0.01),respectively.The V_(5)and D_(mean)of the right lung were 7.82%±3.59%vs 18.41%±11.44%(P<0.01)and(1.97±0.36)Gy vs(3.08±1.12)Gy(P<0.01).The duration of DIBH radiotherapy and FB radiotherapy were 181.00(151.00,229.00)s and 70.20(69.60,70.20)s(P<0.01).After six-dimensional registration of CBCT images,the registration errors of DIBH radiotherapy were less than those of FB radiotherapy in the X,Y,Z,Rx,Rz directions,but not in the Ry direction(P>0.05).Conclusion RGSC-guided DIBH radiotherapy following surgery for left-sided breast cancer can achieve higher treatment accuracy than FB therapy,and reduce the doses exposed to the lung and heart,but increases treatment duration.