| 王锐濠,张书旭,余辉,林生趣,张国前,汤日杰,齐斌,雷怀宇,周祥,蒋绍惠.基于肺通气功能图像引导的调强放疗射野角度优化研究[J].中华放射医学与防护杂志,2015,35(3):201-205 |
| 基于肺通气功能图像引导的调强放疗射野角度优化研究 |
| Beam orientation optimization of pulmonary ventilation image-guided intensity modulated radiotherapy for lung cancer |
| 投稿时间：2014-04-28 |
| DOI：10.3760/cma.j.issn.0254-5098.2015.03.010 |
| 中文关键词: 肺肿瘤/放射疗法 四维CT 肺通气 计划优化 |
| 英文关键词:Lung neoplasms/radiotherapy Four-dimensional computed tomography Pulmonary ventilation Plan optimization |
| 基金项目:国家自然科学基金面上项目(81170078);广东省科技计划项目(2011B031800111);广东省教育厅科技创新项目(2013KJCX152) |
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| 中文摘要: |
| 目的 探讨基于肺通气功能图像引导的肺癌调强放疗中射野角度优化对保护功能肺的剂量学优势。方法 选取拟行调强放疗的非小细胞肺癌患者16例,分别行双相位(呼气末和吸气末)CT定位扫描,将图像传至肺通气功能分析软件系统,获取肺通气功能的三维分布,确定功能肺(FL)区域,并传至治疗计划系统与呼气末CT定位图像进行图像融合。分别设置剂量约束参数制定两类计划:常规的调强放疗(IMRT)计划和肺通气功能图像引导的调强放疗(f-IMRT)计划,每一类计划再分别设计5野均分角度和手动设野两种子计划。IMRT以降低全肺(TL)受量为目标,f-IMRT则以降低功能肺剂量为目标。对比分析IMRT和f-IMRT两类计划中5野均分角度和手动设野之间靶区和正常组织受照的剂量差异。结果 同一类调强放疗计划下,5野均分角度和手动设野之间的PTV剂量学参数差异无统计学意义;手动设野的脊髓、食管和心脏的受量较5野均分角度均有程度不等的变化,但仅食管的平均剂量和心脏V60差异有统计学意义(t=4.33、-2.37,P<0.05)。在IMRT中,5野均分角度中功能肺(FL)的低剂量区受照体积FLV5、FLV10、FLV20分别为(54.2±29.1)%、(42.5±22.1)%、(26.3±20.7)%,手动设野的分别为(30.2±18.5)%、(24.1±12.0)%、(17.8±8.9)%(t=4.87、 4.74、 2.33,P<0.05)。在f-IMRT中,5野均分角度中功能肺(FL)的FLV5、FLV10、FLV20分别为(52.4±20.7)%、(37.1±12.2)%、(21.1±5.8)%,手动设野的分别为(29.2±18.3)%、(23.0±14.8)%、(16.7±9.7)%(t=5.30、4.84、2.23,P<0.05)。全肺(TL)低剂量区剂量学参数也不同程度下降(t=7.96 ~ 6.07,P<0.05)。结论 在肺癌的调强放疗中,结合肺通气功能图像优化放疗计划,并进一步优化射野方向,能有效地降低功能肺的受照剂量,可降低放射性肺炎的发生率和严重程度,改善患者的生活质量。 |
| 英文摘要: |
| Objective To evaluate the dosimetric advantage of pulmonary ventilation image guided intensity-modulated radiotherapy (IMRT) planning in protecting functional lung with optimizing beam orientation.Methods Sixteen non-small cell lung cancer patients were included and carried out with the peak-exhale and peak-inhale CT scans, respectively. The two sets of CT images were then input to the pulmonary ventilation analysis system to acquire the three dimensional distribution of ventilation images. Then the area of better pulmonary ventilation named as functional lung was delineated automatically by the system. The pulmonary ventilation images were fused with CT images by using treatment planning system. Two kinds of IMRT plans were generated, in cluding conventional IMRT, in which the main dose constraints were applied to total lung, as well as f-IMRT, with the main dose constraints applying to functional lung. To evaluate the dosimetric changes of beam arrangement, the five equal-spaced beams and five manual optimization beams were applied to each plan. The dosimetric difference between IMRT and f-IMRT plans was compared using the pairedt-test.Result In the same category of plan, all the dosimetric parameters of PTV had no significant difference (P>0.05) in the plan with FMOB, comparing with FESB. The dose delivered to spinal cord, esophagus, and heart varied in degrees, whereas only the dosimetric difference of the mean dose to esophagus and V60 to heart had statistically significance (t=4.33, -2.37,P<0.05) between the plan with FESB and plan with FMOB. For IMRT plans, compared with FESB, the volume of functional lung at more than 5, 10 and 20 Gy (FLV5, FLV10, and FLV20) decreased significantly in plan with FMOB (t=4.87, 4.74, 2.33,P<0.05). The FLV5, FLV10, and FLV20 in plan with FESB were (54.2±29.1)%, (42.5±22.1)%, (26.3±20.7)%, respectively, while in plan with FMOB were (30.2±18.5)%, (24.1±12.0)%, (17.8±8.9)%, respectively. For f-IMRT plans, compared the plan with FMOB to plan with FESB, the FLV5, FLV10, and FLV20 of the functional lung decreased significantly (t=5.30, 4.84, 2.23,P<0.05). The FLV5, FLV10, and FLV20 were (52.4±20.7)%, (37.1±12.2)%, (21.1±5.8)%, respectively in plan with FESB, while in plan with FMOB were (29.2±18.3)%, (23.0±14.8)%, (16.7±9.7)%, respectively. The dosimetric parameters of low-dose region of total lung also decreased in different degrees, with statistical significance (t=7.96-6.07,P<0.05).Conclusions The combination of pulmonary ventilation images and IMRT, with further optimizing the beam directions, can effectively reduce the radiation dose on functional lung, which is expected to reduce the incidence and severity of radiation pneumonitis and might improve the NSCLC patient's quality of life. |
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