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在我国,乳腺癌位居女性恶性肿瘤发病率的首位[1]。目前,对于早期乳腺癌患者,保乳术后结合放化疗已成为标准治疗方式,其可显著提高肿瘤局部控制率及患者的远期生存率[2]。在行乳腺癌保乳术后,乳腺外形轮廓呈不规则形,而放疗靶区的均匀性和适形性会影响放疗的疗效和并发症的发生。不同的放疗技术在剂量学上存在较大差异,因此优化放疗计划对乳腺癌患者非常重要。传统放疗采用三维适形放疗(three dimensional conformal radiation therapy,3DCRT),由于靶区受呼吸运动的影响,常采用两切线适形野,并将胸廓方向适形的多叶光栅整体外放2 cm,但靶区剂量的均匀性及适形性难以满足要求[3]。适形调强放疗(intensity modulated radiation therapy,IMRT)可提高靶区剂量的均匀性和适形性,减少周边正常组织的受照剂量和受照体积。容积旋转调强放疗(volumetric modulated arc therapy,VMAT)在保证靶区剂量和周围正常组织剂量要求的情况下,大幅度缩短了治疗时间,提高了患者的舒适度和机器的治疗效率。考虑到乳腺癌患者的放疗靶区受呼吸运动影响以及靶区的均匀性和适形性,本研究采用基于固定角度IMRT的混合调强(简称3DCRT+IMRT)、基于VMAT的混合调强(简称3DCRT+VMAT)和切线弧容积旋转调强(tangential volumetric modulated arc therapy,t-VMAT)3种不同的放疗技术对患者进行治疗,并通过比较3种放疗计划的剂量学差异,探讨其临床应用价值。
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早期乳腺癌保乳术后靶区相对简单,12例患者的3种调强计划均能满足临床要求,图2是其中1例患者的3种放疗计划的剂量体积直方图比较,靶区及危及器官的受照剂量均存在一定差异。
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由表1可知,3DCRT+VMAT的CI最大,t-VMAT次之,3DCRT+IMRT最小,3种放疗计划间两两比较,差异均有统计学意义(t=−9.01~4.28,均P<0.01) 。3DCRT+VMAT的HI最小,分别与t-VMAT和3DCRT+IMRT比较,差异均有统计学意义(t=6.47、−2.91,均P<0.05)。3DCRT+IMRT的MU最小,分别与3DCRT+VMAT和t-VMAT比较,差异均有统计学意义(t=−4.07、−3.40,均P<0.05),而3DCRT+VMAT的MU与t-VMAT比较,差异无统计学意义(t=2.14,P=0.06)。
放疗计划 CI HI MU 3DCRT+IMRT 0.74±0.06 0.14±0.03 280.90±52.18 3DCRT+VMAT 0.84±0.05a 0.10±0.03a 360.02±41.55a t-VMAT 0.79±0.06a,b 0.13±0.03b 336.57±42.34a 注:表中,a为与3DCRT+IMRT比较,差异有统计学意义(t=−9.01~6.47,均P<0.05);b为与3DCRT+VMAT比较,差异有统计学意义(t=4.28、−2.91,均P<0.05)。3DCRT+IMRT:基于固定角度适形调强放疗的混合调强;3DCRT+VMAT:基于容积旋转调强放疗的混合调强;t-VMAT:切线弧容积旋转调强;CI:适形性指数;HI:均匀性指数;MU:机器跳数 表 1 左侧乳腺癌保乳术后3种放疗计划的靶区剂量学指标 的比较(n=12,
)$\bar{{x}}\pm {s}$ Table 1. Comparison of target dosimetric parameters of three radiotherapy plans after breast conserving surgery for left breast cancer(n=12,
)$\bar{{x}}\pm {s}$ -
由表2可知,在患侧(左)肺受照剂量体积比较中,3DCRT+IMRT的
$ {\rm{V}}_{5}{\text{、}}{\rm{D}}_{\rm{m}\rm{e}\rm{a}\rm{n}} $ 数值最小,3DCRT+VMAT次之,t-VMAT最大,3种放疗计划间两两比较,差异均有统计学意义(t=−7.67~−2.65,均P<0.05);3DCRT+IMRT和3DCRT+VMAT的V10、V20均小于t-VMAT,且差异均有统计学意义(t=−7.02~−5.51,均 P<0.05),但3DCRT+IMRT的V10、V20与3DCRT+VMAT的比较,差异均无统计学意义(t=−2.05、1.00,均P>0.05)。在健侧(右)肺受照剂量体积比较中,3DCRT+IMRT的V5、Dmean数值最小,3DCRT+VMAT与t-VMAT之间的比较,差异均无统计学意义(t=−0.68、0.14,均P>0.05)。在心脏受照剂量体积比较中,3DCRT+VMAT的V30、V40最小,3DCRT+IMRT的Dmean最小,t-VMAT的V30、V40、Dmean均最大,3种放疗计划间两两比较,差异均有统计学意义(t=−17.11~3.45,均P<0.05)。在健侧(右)乳腺受照剂量体积比较中,3DCRT+IMRT和3DCRT+VMAT的V5小于t-VMAT,但3DCRT+VMAT与3DCRT+IMRT间的比较,差异无统计学意义(t=−1.44, P=0.18), 3DCRT+IMRT的Dmean最小,与其他两种放疗计划比较,差异均有统计学意义(t=−8.21、−6.60,均P<0.05)。放疗计划 左肺 右肺 心脏 右乳腺 V5(%) V10(%) V20(%) Dmean(Gy) V5(%) Dmean(Gy) V30(%) V40(%) Dmean(Gy) V5(%) Dmean(Gy) 3DCRT+IMRT 35.92±8.01 25.50±6.91 17.50±5.70 10.14±2.43 0.50±1.45 0.55±0.21 5.00±3.25 3.25±2.53 6.18±2.01 0.17±0.58 0.86±0.38 3DCRT+VMAT 49.33±12.05a 26.92±7.23 17.33±5.68 11.07±2.88a 2.17±3.76 1.79±0.58a 4.50±2.88a 2.50±2.11a 7.11±1.77a 1.92±4.10 1.65±0.45a t-VMAT 60.58±12.94a,b 41.25±10.37a,b 24.67±8.59a,b 14.52±3.32a,b 3.00±4.94a 1.75±0.70a 8.42±2.78a,b 4.58±2.07a,b 10.91±2.58a,b 8.25±8.61a,b 2.46±0.86a,b 注:表中,a为与3DCRT+IMRT比较,差异有统计学意义(t=−8.21~3.45,均 P<0.05);b为与3DCRT+VMAT比较,差异有统计学意义(t=−17.11~−2.73,均 P<0.05)。3DCRT+IMRT:基于固定角度适形调强放疗的混合调强;3DCRT+VMAT:基于容积旋转调强放疗的混合调强;t-VMAT:切线弧容积旋转调强;V5:≥5 Gy体积占总体积的百分比;V10:≥10 Gy体积占总体积的百分比;V20:≥20 Gy体积占总体积的百分比;Dmean:平均剂量;V30:≥30 Gy体积占总体积的百分比;V40:≥40 Gy体积占总体积的百分比 表 2 左侧乳腺癌保乳术后3种放疗计划危及器官的剂量学参数的比较(n=12,
)$\bar{{x}}\pm {s}$ Table 2. Comparison of dosimetric parameters of organs at risk after breast conserving surgery for left breast cancer(n=12,
)$\bar{{x}}\pm {s}$
3种不同放疗技术在左侧乳腺癌保乳术后全乳腺放疗中的剂量学比较
Dosimetric comparison of three different radiotherapy techniques in whole breast radiotherapy after breast-conserving surgery for left breast cancer
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摘要:
目的 比较3种调强放疗技术在早期左侧乳腺癌保乳术后全乳腺放疗中的剂量学差异。 方法 回顾性分析2019年3月至8月在西安交通大学第一附属医院治疗的12例早期左侧乳腺癌保乳术后女性患者,年龄32~50(42.4±6.8)岁。分别设计基于固定角度适形调强放疗的混合调强(3DCRT+IMRT)、容积旋转调强放疗的混合调强(3DCRT+VMAT)和切线弧容积旋转调强放疗计划(t-VMAT),并比较3种放疗计划的计划靶区、危及器官剂量参数以及治疗效率的差异。组间数据比较采用配对t检验。 结果 3种调强放疗计划的靶区剂量分布和危及器官受量均能满足临床要求。3DCRT+IMRT和t-VMAT两种计划相比,3DCRT+VMAT的靶区剂量学指标适形性指数(0.84±0.05对0.74±0.06对0.79±0.06)和均匀性指数(0.10±0.03对0.14±0.03对0.13±0.03)最优,差异均有统计学意义(t=−9.01~6.47,均P<0.05);3DCRT+IMRT对患侧(左)肺的V5[(35.92±8.01)%对(49.33±12.05)%对(60.58±12.94)%]、V10[(25.50±6.91)%对(26.92±7.23)%对(41.25±10.37)%]、Dmean[(10.14±2.43)Gy对(11.07±2.88)Gy对(14.52±3.32)Gy]和健侧(右)肺的V5[(0.50±1.45)%对(2.17±3.76)%对(3.00±4.94)%]、Dmean[(0.55±0.21)Gy对(1.79±0.58)Gy对1.75±0.70)Gy]及健侧(右)乳腺的V5[(0.17±0.58)%对(1.92±4.10)%对(8.25±8.61)%]、Dmean[(0.86±0.38)%对(1.65±0.45)%对(2.46±0.86)%]的保护最好。3DCRT+VMAT的心脏V30[(4.50±2.88)%对(5.00±3.25)%对(8.42±2.78)%]、V40[(2.50±2.11)%对(3.25±2.53)%对(4.58±2.07)%]明显优于3DCRT+IMRT和t-VMAT,且差异均有统计学意义(t=−17.11~3.45,均P<0.05)。3DCRT+IMRT的平均机器跳数最小(280.90±52.18),t-VMAT的治疗时间最短。 结论 3DCRT+IMRT在低剂量区(<20 Gy)对健侧肺、患侧肺,健侧乳腺等危及器官的保护比较好,3DCRT+VMAT在提高靶区的均匀性和适形性方面有明显优势,且在高剂量区(>20 Gy)对患侧肺及心脏保护更好,t-VMAT缩短了治疗时间,提高了治疗效率和患者舒适度。 -
关键词:
- 乳腺肿瘤 /
- 放射治疗计划,计算机辅助 /
- 放射疗法,调强适形 /
- 容积旋转调强放疗 /
- 剂量学
Abstract:Objective To compare the dosimetry of three different intensity-modulated radiation therapy (IMRT) techniques in patients undergoing whole-breast radiotherapy after breast-conserving surgery for early left breast cancer. Methods Between March 2019 and August 2019, 12 female patients with early left breast cancer who underwent breast-conservative surgery in the First Affiliated Hospital of Xi'an Jiaotong University were analyzed retrospectively. The patient age was between 32 and 50 years, with an average of 42.4±6.8 years. The IMRT-based hybrid plan (3D conformal radiation therapy or 3DCRT + IMRT), the volumetric modulated arc therapy (VMAT)-based hybrid plan (3DCRT+VMAT), and the tangential VMAT plan (t-VMAT) were designed. The dosimetric parameters of the target and the organs at risk and treatment efficiency were compared among the three plans, and t-test was used for data analysis. Results Both the dose distribution in the target and dose to the organs at risk can meet the clinical requirements of the three plans. The conformal index (0.84±0.05 vs. 0.74±0.06 vs. 0.79±0.06) and uniformity index (0.10±0.03 vs. 0.14±0.03 vs. 0.13±0.03) of 3DCRT+VMAT were the best, and the difference was statistically significant compared with the two other plans (t=–9.01–6.47, all P<0.05). The protective effect of 3DCRT+IMRT was the best for V5 ((35.92±8.01)% vs. (49.33±12.05)% vs. (60.58±12.94)%), V10 ((25.50±6.91)% vs. (26.92±7.23)% vs. (41.25±10.37)%), Dmean ((10.14±2.43) Gy vs. (11.07±2.88) Gy vs. (14.52±3.32) Gy) of the ipsilateral (left) lung, V5( (0.50±1.45)% vs.(2.17±3.76)% vs. (3.00±4.94)%), and Dmean ((0.55±0.21) Gy vs. (1.79±0.58) Gy vs. (1.75±0.70) Gy) of the contralateral (right) lung and the V5 ((0.17±0.58)% vs. (1.92±4.10)% vs. (8.25±8.61)%) and Dmean ((0.86±0.38) Gy vs. (1.65±0.45) Gy vs. (2.46±0.86) Gy) of the contralateral (right) breast. 3DCRT+VMAT was significantly better than 3DCRT+IMRT and t-VAMT in V30 ((4.50±2.88)% vs. (5.00±3.25)% vs. (8.42±2.78)%) and V40 ((2.50±2.11)% vs. (3.25±2.53)% vs. (4.58±2.07)%) of the heart (t=–17.11–3.45, all P<0.05). The mean monitor unit of 3DCRT+IMRT was the lowest (280.90±52.18), but the treatment time of t-VMAT was the shortest. Conclusions The protective effect of 3DCRT+IMRT in the low-dose area (<20 Gy) for the ipsilateral lung, contralateral lung, and contralateral breast was better. 3DCRT+VMAT has obvious advantages in improving the uniformity and conformability of the target area and has better protection in the high-dose area (>20 Gy) for the contralateral lung and heart. Thus, t-VMAT shortens the treatment time and improves treatment efficiency and patient comfort. -
表 1 左侧乳腺癌保乳术后3种放疗计划的靶区剂量学指标 的比较(n=12,
)$\bar{{x}}\pm {s}$ Table 1. Comparison of target dosimetric parameters of three radiotherapy plans after breast conserving surgery for left breast cancer(n=12,
)$\bar{{x}}\pm {s}$ 放疗计划 CI HI MU 3DCRT+IMRT 0.74±0.06 0.14±0.03 280.90±52.18 3DCRT+VMAT 0.84±0.05a 0.10±0.03a 360.02±41.55a t-VMAT 0.79±0.06a,b 0.13±0.03b 336.57±42.34a 注:表中,a为与3DCRT+IMRT比较,差异有统计学意义(t=−9.01~6.47,均P<0.05);b为与3DCRT+VMAT比较,差异有统计学意义(t=4.28、−2.91,均P<0.05)。3DCRT+IMRT:基于固定角度适形调强放疗的混合调强;3DCRT+VMAT:基于容积旋转调强放疗的混合调强;t-VMAT:切线弧容积旋转调强;CI:适形性指数;HI:均匀性指数;MU:机器跳数 表 2 左侧乳腺癌保乳术后3种放疗计划危及器官的剂量学参数的比较(n=12,
)$\bar{{x}}\pm {s}$ Table 2. Comparison of dosimetric parameters of organs at risk after breast conserving surgery for left breast cancer(n=12,
)$\bar{{x}}\pm {s}$ 放疗计划 左肺 右肺 心脏 右乳腺 V5(%) V10(%) V20(%) Dmean(Gy) V5(%) Dmean(Gy) V30(%) V40(%) Dmean(Gy) V5(%) Dmean(Gy) 3DCRT+IMRT 35.92±8.01 25.50±6.91 17.50±5.70 10.14±2.43 0.50±1.45 0.55±0.21 5.00±3.25 3.25±2.53 6.18±2.01 0.17±0.58 0.86±0.38 3DCRT+VMAT 49.33±12.05a 26.92±7.23 17.33±5.68 11.07±2.88a 2.17±3.76 1.79±0.58a 4.50±2.88a 2.50±2.11a 7.11±1.77a 1.92±4.10 1.65±0.45a t-VMAT 60.58±12.94a,b 41.25±10.37a,b 24.67±8.59a,b 14.52±3.32a,b 3.00±4.94a 1.75±0.70a 8.42±2.78a,b 4.58±2.07a,b 10.91±2.58a,b 8.25±8.61a,b 2.46±0.86a,b 注:表中,a为与3DCRT+IMRT比较,差异有统计学意义(t=−8.21~3.45,均 P<0.05);b为与3DCRT+VMAT比较,差异有统计学意义(t=−17.11~−2.73,均 P<0.05)。3DCRT+IMRT:基于固定角度适形调强放疗的混合调强;3DCRT+VMAT:基于容积旋转调强放疗的混合调强;t-VMAT:切线弧容积旋转调强;V5:≥5 Gy体积占总体积的百分比;V10:≥10 Gy体积占总体积的百分比;V20:≥20 Gy体积占总体积的百分比;Dmean:平均剂量;V30:≥30 Gy体积占总体积的百分比;V40:≥40 Gy体积占总体积的百分比 -
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