乳腺癌改良根治术后三种放疗技术的剂量学对比研究

目的 分析比较容积调强弧形治疗(VMAT)与固定野调强放疗(F_IMRT)、电子束联合VMAT (E&VMAT)技术在乳腺癌改良根治术后放疗中的剂量学差异,为临床选择治疗方案提供参考。方法 随机选择乳腺癌改良根治术后放疗的左乳腺癌患者 10例,靶区包括患侧胸壁和锁骨上淋巴引流区,处方剂量43.5Gy (2.9 Gy/次)。基于Pinnacle³计划系统为每位患者分别设计VMAT、F_IMRT、E&VMAT (胸壁靶区部分电子束照射、锁骨上区部分VMAT照射)计划。对比评价靶区剂量分布适形度与均匀性、危及器官受量以及治疗实施时间。结果 VMAT计划能改善靶区剂量分布,靶区剂量适形指数和均匀性指数均优于F_IMRT和E&VMAT计划(均 P<0.05)。VMAT计划患侧肺平均剂量 、V30Gy、V20Gy、V10Gy均优于F_IMRT和E&VMAT计划(均 P<0.05)。VMAT计划患侧 肺V5Gy优于F_IMRT计划(P<0.05),与E&VMAT计划 的V5Gy相近(P>0.05)。VMAT计划的心脏、健侧乳腺、健侧肺均能满足临床剂量限制要求。VMAT、F_IMRT、E&VMAT计划的治疗时间分别为(326±27)、(1082±169)、(562±48) s。结论 与F_IMRT和E&VMAT计划相比,VMAT计划质量更优,治疗时间更短,具有较高的临床应用价值。

Dosimetric comparison of three techniques in radiotherapy for breast cancer after modified mastectomy

Objective To analyze and compare the dosimetric differences based on volumetric-modulated arc therapy (VMAT), fixed field intensity-modulated radiotherapy (F_IMRT), and electron irradiation combined with VMAT (E&VMAT) in radiotherapy for breast cancer after modified mastectomy, aiming to provide reference for clinical selection of treatment plan. Methods Ten patients with the left breast cancer who received radiotherapy after modified mastectomy were randomly selected. The target areas included chest wall and supraclavicular region, and the prescribed dose was 43.5Gy in 15 fractions (2.9Gy/F). Based on the Pinnacle³ planning system, the VMAT, F_IMRT and E&VMAT plans (electron beam for chest wall, VMAT for supraclavicular area) were designed for each patient. The conformity and homogeneity of the target areas, the dose of organs at risk and treatment time were compared. Results The VMAT plan could improve the dose distribution of the target areas. The conformity index and homogeneity index of the target dose were significantly better than those of the F_IMRT and E&VMAT plans (all P<0.05). The average dose, V30Gy, V20Gy, V10Gy of the left lung in the VMAT plan were significantly better than those in the F_IMRT and E&VMAT plans (all P<0.05). The V5Gy of the left lung in the VMAT plan was significantly better than that in the F_IMRT plan (P<0.05). There was no statistical difference in the V5Gy of the left lung between the VMAT and E&VMAT plans (P>0.05). The heart, right breast and right lung of the VMAT plan could meet the clinical dose limit requirements. The treatment time of the VMAT, F_IMRT and E&VMAT plans was (326±27) s,(1 082±169) s, and (562±48) s, respectively. Conclusions Compared with the F_IMRT and E&VMAT plans, the VMAT plan has better quality and shorter treatment time. VMAT plan has higher value in clinical application compared with the F_IMRT and E&VMAT plans.