| 赵强,吴湘阳,常晓斌,冯涛,杨迪,屈喜梅,王学敏,邓佳.形变配准在宫颈癌近距离放疗分次间剂量评估中的可行性研究[J].中华放射医学与防护杂志,2022,42(3):204-209 |
| 形变配准在宫颈癌近距离放疗分次间剂量评估中的可行性研究 |
| Feasibility of application of deformable image registration to the dosimetry assessment of fractionated brachytherapy for cervical cancer |
| 投稿时间：2021-10-29 |
| DOI：10.3760/cma.j.cn112271-20211029-00430 |
| 中文关键词: 形变配准 近距离放疗 宫颈癌 |
| 英文关键词:Deformable image registration Brachytherapy Cervical cancer |
| 基金项目: |
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| 中文摘要: |
| 目的 比较近距离放疗分次间靶区和正常组织在形变配准（DIR）和简单累加剂量体积直方图（DVH）情况下，累积剂量的剂量学差异，分析在宫颈癌三维近距离放疗计划中，形变配准技术应用于靶区和正常组织剂量评估的可行性。方法 回顾性选取13例宫颈癌近距离放疗病例，每个病例均进行了4次CT定位的近距离放疗。对每个病例的4次CT进行形变配准后，计算并统计靶区D90和膀胱、直肠、小肠、结肠D2 cm3、D1 cm3、D0.1 cm3的形变累积剂量，与简单累加DVH得到的累积剂量进行对比，分析剂量差异与相似系数（DSC）的相关性。以此剂量差异（即形变配准造成的正常组织剩余剂量）作为限量，在最新一次的CT上重新做计划，分析此差异给靶区剂量提升带来的收益。结果 经形变配准后，膀胱D2 cm3、D1 cm3的累积剂量分别比简单累加DVH低（2.47±1.92）、（2.82±2.73）Gy（t=-3.65、-2.93，P<0.05）；直肠D2 cm3、D1 cm3、D0.1 cm3的累积剂量分别比简单累加DVH低（2.05±1.61）、（1.51±1.58）、（3.21±2.50）Gy（t=-4.02、-3.02、-4.06，P<0.05）；小肠D2 cm3、D1 cm3、D0.1 cm3的累积剂量分别比简单累加DVH低（1.42±0.99）、（1.55±1.28）、（2.43±1.95）Gy（t=-3.52、-2.96、-3.06，P<0.05）。靶区D90、膀胱D0.1 cm3和结肠D2 cm3、D1 cm3、D0.1 cm3的差异无统计学意义（P>0.05）。DSC和剂量差异相关性不明显（P>0.05）。利用形变配准可一定程度上提升靶区剂量，中位数为150 cGy。但形变配准精度有待提高。结论 在宫颈癌三维近距离放疗分次间，仍建议采用简单剂量累加方法评估靶区和危及器官累积剂量。 |
| 英文摘要: |
| Objective To study the differences in the cumulative dose between deformable image registration (DIR) and simple dose-volume histogram (DVH) summation in the fractionated brachytherapy of cervical cancer, and to analyze the feasibility of the application of DIR in the dosimetry assessment of targets and organs-at-risk (OARs) in the brachytherapy. Methods A retrospective analysis was conducted for 13 cases with primary cervical cancer treated with four fractions of interstitial brachytherapy guided by CT images. The four CT images of each cases were registered using an intensity-based DIR. Then, the cumulative doses (the D2 cm3, D1 cm3, and D0.1 cm3 of the bladder, rectum, intestine, and colon and the D90for targets) after DIR were calculated and compared to those obtained using simple DVH summation. Afterward, the correlation between the dose difference and dice similarity coefficient (DSC) was analyzed. With the dose difference (the remaining dose of OARs caused by the DIR) as limits, a new plan was made for the latest CT to calculate the dose increase to targets. Results Compared to simple DVH summation, DIR allowed the cumulative doses of the D2 cm3 and D1 cm3 of bladder to be decreased by (2.47±1.92) and (2.82±2.73) Gy, respectively on average (t=-3.65, -2.93, P<0.05), those of the D2 cm3, D1 cm3, and D0.1 cm3 of rectum to be decreased by (2.05±1.61) Gy, (1.51±1.58), and (3.21±2.50) Gy, respectively on average (t=-4.02, -3.02, -4.06, P<0.05), and those of the D2 cm3, D1 cm3, and D0.1 cm3 to be decreased by (1.42±0.99), (1.55±1.28) Gy, and (2.43±1.95) Gy, respectively on average (t=-3.52, -2.96, -3.06, P<0.05). There was no significant statistical difference in the D90 of targets, the D0.1 cm3 of the bladder, and the D2 cm3, D1 cm3, D0.1 cm3 of the colon (P>0.05) between both methods, and there was no distinct correlation between DSC and dose difference (P>0.05). The DIR increased the dose to targets, with a median value of 150 cGy. However, the accuracy of the DIR should be improved. In clinical practice of multiple fractions of brachytherapy for cervical cancer, it's still recommended to adopt the simple dose summation method to assess the doses to targets and OARs. |
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