深吸气屏气技术对左侧乳腺癌术后包含内乳淋巴结调强放疗的心脏剂量学影响

Effects of the deep inspiration breath-hold technique on cardiac dosimetry in internal mammary node irradiation with intensity-modulated radiation therapy for postoperative left breast cancer

目的探索左侧乳腺癌术后包含内乳淋巴结调强放疗时,实施深吸气屏气技术(DIBH)对心脏剂量学的影响。方法观察2021年10月至2022年7月蚌埠医学院第一附属医院23例左侧乳腺癌术后行包含内乳淋巴结调强放疗(IMRT)患者心脏和冠状动脉左前降支(LAD)在DIBH时相上剂量学参数的变化,并分析其实施效果的潜在影响因素。结果与自由呼吸(FB)相比,DIBH状态下心脏体积缩小18%(t=10.47,P<0.001)、左肺体积扩张42%(t=-14.55,P<0.001),心脏及LAD的平均剂量D_(mean)、最大剂量D_(max)以及剂量体积参数V_(5)~V_(30)均明显降低,差异具有统计学意义(t=-13.38~-3.30,P<0.05);相关性分析显示,左肺扩张的相对比值与心脏剂量减少的相对比值呈正相关(r=0.82,P<0.001),患者年龄与心脏剂量减少的相对比值呈负相关(r=-0.56,P=0.005)。结论本研究明确了左侧乳腺癌术后包含内乳淋巴结IMRT时实施DIBH,可有效地降低心脏及LAD的剂量,年龄和肺活量可能是DIBH实施效果的影响因素。

Objective To explore the effects of the deep inspiration breath-hold(DIBH)technique on cardiac dosimetry in internal mammary node irradiation with intensity-modulated radiation therapy(IMN-IMRT)for postoperative left breast cancer.Methods Totally 23 left breast cancer patients in the First Affiliated Hospital of Bengbu Medical College from Octorber 2021 to July 2022 receiving postoperative IMN-IMRT were enrolled in this study.The changes in dosimetric parameters for their heart and left anterior descending coronary artery(LAD)in the DIBH mode were observed,and the potential factors affecting DIBH effects were analyzed.Results Compared with the free breath(FB)mode,the DIBH mode manifested a heart volume decrease by 18%(t=10.47,P<0.001),a left lung volume increase by 42%(t=-14.55,P<0.001),and significantly reduced dosimetric parameters(D_(mean),D_(max),V_(5)-V_(30))for the heart and LAD,exhibiting statistically significant differences(t=-13.38 to-3.30,P<0.05).As indicated by the Pearson correlation analysis,the relative ratio of cardiac dose reduction was positively correlated with that of left lung expansion(r=0.82,P<0.001)and negatively correlated with the patient′age(r=-0.56,P=0.005).Conclusions DIBH can effectively reduce the heart and LAD radiation doses in IMN-IMRT for postoperative left breast cancer and that the patient's age,and the DIBH effects might be affected by the vital capacity.