| 陈诚,鲍志荣,於海军,等.改进式的二维图像配准算法在头颈部肿瘤中的应用[J].中华放射医学与防护杂志,2017,37(9):690-695.Chen Cheng,Bao Zhirong,Yu Haijun,et al.Improved 2D image registration algorithm applied to head and neck tumor[J].Chin J Radiol Med Prot,2017,37(9):690-695 |
| 改进式的二维图像配准算法在头颈部肿瘤中的应用 |
| Improved 2D image registration algorithm applied to head and neck tumor |
| 投稿时间：2017-02-09 |
| DOI：10.3760/cma.j.issn.0254-5098.2017.09.010 |
| 中文关键词: 摆位误差 电子射野影像装置 射野图像 图像配准 |
| 英文关键词:Setup errors Electronic portal imaging device Portal image Image registration |
| 基金项目: |
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| 摘要点击次数: 3195 |
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| 中文摘要: |
| 目的 研究摆位误差导致的二维图像投影变化及其对图像配准的影响，提出一种改进的互信息配准算法。方法 借助仿真头部体模，分别模拟旋转误差和平移误差，通过互信息的变化来反映投影形变。以3mm平移误差和3°旋转误差为界，模拟10例较小摆位误差和10例较大摆位误差，拍摄正侧位射野图像，分别使用目前加速器自带的传统互信息配准方法和本研究改进的互信息配准方法获取摆位误差，并与实际摆位误差相比较，以判断本研究提出的改进配准方法的优劣。结果 对于摆位误差较小的实例，加速器自带的传统互信息配准方法的x、y、z轴平均平移误差分别为0.3、0.4和0.3 mm，x、z轴平均旋转误差均为0.4°，平均耗时28.7 s。本研究改进的互信息配准方法的平均误差为0.4、0.3和0.3 mm，x、z轴平均旋转误差分别为0.5°和0.4°，平均耗时31.1 s。对于摆位误差较大的实例，加速器自带的传统互信息配准方法的平均误差分别为0.9、0.7和0.8 mm，x、z轴平均旋转误差为0.9°和0.8°，平均耗时29.9 s，本研究的改进互信息方法平均误差分别为0.5、0.4和0.5 mm，x、z轴平均旋转误差分别为0.6°和0.5°，平均耗时33.2 s。结论 对于较小的摆位误差，两种方法都具有较高的配准精度，但对于较大的摆位误差，本研究改进互信息配准方法较加速器自带的互信息配准方法具有显着的精度优势，并且配准耗时也在临床可以接受的范围内。 |
| 英文摘要: |
| Objective To evaluate the effect of setup errors on the 2D image projection and image registration, and then propose an improved registration method based on mutual information.Methods An anthropomorphic head phantom was used to simulate the rotational and translational setup errors. The geometric disparities were reflected by the changes of mutual information. Known setup errors were intentionally introduced to twenty cases divided into two groups demarcated by 3 mm translation error and 3° rotation error: ten cases with larger errors and ten with smaller errors. Then the anterior-posterior and lateral portal images were captured by the electronic portal imaging device (EPID), based on which the setup errors were calculated using two mutual information registration method respectively: the vender provided one, and the improved method as proposed. The calculated errors were compared with the actual setup errors to evaluate robustness of the method.Results For the ten cases with smaller setup errors, the average translational registration disparities using the conventional method were 0.3, 0.4, and 0.3 mm in x, y and z directions respectively. The rotational disagreements were 0.4° in both x and z directions. The average time consumption was 28.7 s. The corresponding discrepancies analyzed using the improved method were 0.3, 0.4, 0.3 mm, 0.5° and 0.4°, respectively. On average, 31.1 s was needed for registration. For the ten cases with larger setup errors, the mean disparities of the conventional method were 0.9, 0.7, 0.8 mm, 0.9° and 0.8°, 29.9 s taken on average. The corresponding result of the improved method was 0.5, 0.4, 0.5 mm, 0.6° and 0.5°, 33.2 s taken on average.Conclusions Regarding smaller setup errors, the two methods showed little difference and both had good performance in image registration accuracy. For larger setup errors, however, the improved mutual information registration method exhibited significantly higher accuracy than the conventional method, at cost of clinically acceptable registration time. |
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