基于本底剂量计划功能的两种调强技术在乳腺癌保乳治疗中的应用研究

龚筱钦; 杨灵杰; 陈飞; 李春梅; 胡静; 戴春华; 游涛

doi:10.3969/j.issn.2095-5227.2022.03.009

基于本底剂量计划功能的两种调强技术在乳腺癌保乳治疗中的应用研究

Application of two intensity modulation techniques based on base dose planning function in breast cancer breast-conserving therapy

摘要

摘要:
背景乳腺癌患者受照的放疗剂量对治疗后生活质量有着较大影响。基于瓦里安Eclipse计划优化系统中的本底剂量计划(base dose plan，BDP)功能，对乳腺癌保乳治疗的患者设计调强技术和混合调强技术放疗计划，为BDP功能应用于临床提供数据支持。
目的基于瓦里安Eclipse计划优化系统中的BDP功能，比较无锁骨上淋巴结转移情况下乳腺癌调强技术与混合调强技术的剂量学差异及验证通过率。
方法选取2018年8月- 2020年12月于江苏大学附属医院治疗的15例乳腺癌保乳术后无锁骨上淋巴结转移的患者，年龄35 ~ 65岁，均为女性。分别根据同一CT模拟定位图像设计调强放射治疗(intensity modulated radiotherapy，IMRT)和混合调强放射治疗(hybrid intensity modulated radiotherapy，Hy_IMRT)计划，比较不同计划95%、105%的处方剂量覆盖靶区体积的百分数(V95%、V105%)、靶区适形指数(conformity index，CI)、均匀性指数(homegeneity index，HI)、最大剂量(D_max)、平均剂量(D_mean)、不同危及器官的剂量差异以及治疗计划机器跳数(monitor unit，MU)，并采用瓦里安系统中的BDP功能对15例乳腺癌患者进行两种计划剂量验证对比，分析验证通过率。
结果计划指标比较：Hy_IMRT计划中的计划靶区V105%、D_max、D_mean、CI低于IMRT(P＜0.05)；患侧肺D_mean、V20_Gy、V30_Gy、V40_Gy，Hy_IMRT高于IMRT(P＜0.05)，左侧和右侧肺的V5_Gy，Hy_IMRT均低于IMRT(P＜0.05)；心脏的D_mean、V10_Gy及V20_Gy，Hy_IMRT低于IMRT(P＜0.05)，而心脏的V30_Gy、V40_Gy差异无统计学意义(P＞0.05)；健侧乳腺D_mean，Hy_IMRT低于IMRT(P＜0.05)；脊髓D_max，Hy_IMRT低于IMRT(P＜0.05)；Hy_IMRT计划MU少于IMRT(P＜0.05)。剂量验证结果：Hy_IMRT与IMRT通过率相似(P＞0.05)。
结论相比Hy_IMRT技术，IMRT的靶区有更高的平均剂量，在降低危及器官的高剂量区上更有优势；而Hy_IMRT能更好地保护危及器官的低剂量区，并提高治疗效率。

Abstract:
Background The radiotherapy dose of breast cancer patients has great influence on the quality of life after treatment. Based on base dose plan (BDP) function in the Varian Eclipse planning optimization system, two different radiotherapy plans are designed for breast cancer patients with breast conserving therapy, namely, intensity modulated technology and mixed intensity modulated radiotherapy, so as to improve data support for clinical application of BDP function.
Objective To compare the dosimetric differences and validation pass rates of breast cancer intensity modulated radiotherapy techniques and hybrid intensity modulated radiotherapy without supraclavicular lymph node prophylaxis based on the BDP function in the Varian Eclipse planning optimization system.
Methods From August 2018 to December 2020, 15 cases of female breast cancer without prevention of supraclavicular lymph nodes after breast conserving surgery were treated in the Affiliated Hospital of Jiangsu University, with the age range of 35-65 years. Intensity modulated radiotherapy (IMRT) and hybrid intensity modulated radiotherapy (Hy_IMRT) were designed according to the same CT image, the dose differences of target volume percentage (V95%, V105%), target conformity index (CI) and homegeneity index (HI), the maximum dose (D_max) and mean dose (D_mean), different organs at risk (OAR) and monitor unit (MU) were compared among the two different plans, the BDP function of varian system was used to analyze the pass rate of two validation plans in the 15 breast cancer patients.
Results In the Hy_IMRT plan, the planned target volume (PTV) V105%, D_max, D_mean and CI were lower than IMRT (all P＜0.05). Hy_IMRT was higher in terms of D_mean, V20_Gy, V30_Gy and V40_Gy of the affected lung than those in IMRT (all P＜0.05). The V5_Gy of the left and right lung, the D_mean, V10_Gy and V20_Gy of the heart, the D_mean of healthy breast, and the spinal cord D_max were all significantly lower in Hy_IMRT than those in the IMRT (all P＜0.05), but there was no significant difference in V30_Gy and V40_Gy of the heart (P＞0.05). In terms of MU, Hy_IMRT plan was also lower than IMRT (P＜0.05). Dose verification results showed that the passing rates of the two groups were similar (P＞0.05).
Conclusion Compared with Hy_IMRT, IMRT has a higher mean dose in target area and a better advantage in reducing the high dose area which endangers organs, while Hy_IMRT can protect the low dose area which endangers organs and improve the therapeutic efficiency.

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