Objective To explore the differences in three different registration methods of cone beam computed tomography(CBCT)-guided down-regulated intense radiation therapy for lung cancer as well as the effects of tumor locat...Objective To explore the differences in three different registration methods of cone beam computed tomography(CBCT)-guided down-regulated intense radiation therapy for lung cancer as well as the effects of tumor location,treatment mode,and tumor size on registration.Methods This retrospective analysis included 80 lung cancer patients undergoing radiotherapy in our hospital from November 2017 to October 2019 and compared automatic bone registration,automatic grayscale(t+r)registration,and automatic grayscale(t)positioning error on the X-,Y-,and Z-axes under three types of registration methods.The patients were also grouped according to tumor position,treatment mode,and tumor size to compare positioning errors.Results On the X-,Y-,and Z-axes,automatic grayscale(t+r)and automatic grayscale(t)registration showed a better trend.Analysis of the different treatment modes showed differences in the three registration methods;however,these were not statistically significant.Analysis according to tumor sizes showed significant differences between the three registration methods(P<0.05).Analysis according to tumor positions showed differences in the X-and Y-axes that were not significant(P>0.05),while the autopsy registration in the Z-axis showed the largest difference in the mediastinal and hilar lymph nodes(P<0.05).Conclusion The treatment mode was not the main factor affecting registration error in lung cancer.Three registration methods are available for tumors in the upper and lower lungs measuring<3 cm;among these,automatic gray registration is recommended,while any gray registration method is recommended for tumors located in the mediastinal hilar site measuring<3 cm and in the upper and lower lungs≥3 cm.展开更多
Currently the voxel based registration methods have been used widely such as the well known mutual information (MI). Although the accuracy of their results is plausible, the registration procedure is slow. This paper ...Currently the voxel based registration methods have been used widely such as the well known mutual information (MI). Although the accuracy of their results is plausible, the registration procedure is slow. This paper proposed some methods to rigid registration based on mutual information, aiming for an acceleration of the registration process without significantly loss of precision in the final results. The efficiency of these methods is examined by registration of CT MR and PET MR. Experimental results show that the speedup is effective and efficient. By using the fast methods, the registration of 3 D medical image could also be implemented on PC rapidly.展开更多
Three characteristic points in the deformation history of a fractured tensile specimen are selected tocalculate two values of n( n1 and n2 ) to represent the hardening ability of material during the homogeneous plas-t...Three characteristic points in the deformation history of a fractured tensile specimen are selected tocalculate two values of n( n1 and n2 ) to represent the hardening ability of material during the homogeneous plas-tic deformation and the following large plastic deformation. Experimental results obtained with mild streel andred copper show that n determined using the three-point method proposed is better to describe the hardening a-bility of material. It is therefore concluded that three-point method can be used to describe the hardening prop-erty of material during both homogeneous deformation and large plastic deformation.展开更多
目的:研究iCBCT引导前列腺癌调强放疗中盆腔淋巴引流区和前列腺精囊腺靶区位移的差异性,为临床上选择合理的图像引导策略提供参考依据。方法:回顾性选取2023年01月至2023年09月在中山大学肿瘤防治中心进行调强放疗的21例前列腺癌患者,...目的:研究iCBCT引导前列腺癌调强放疗中盆腔淋巴引流区和前列腺精囊腺靶区位移的差异性,为临床上选择合理的图像引导策略提供参考依据。方法:回顾性选取2023年01月至2023年09月在中山大学肿瘤防治中心进行调强放疗的21例前列腺癌患者,要求患者在定位及治疗前充盈膀胱、排空直肠,对患者治疗前扫描的iCBCT影像分别以盆腔骨性结构、前列腺精囊腺为参考进行离线配准(自动配准后手动调整),分别评估盆腔淋巴引流区、前列腺精囊腺的靶区位移误差,得到左右(left-right,LR)、头脚(superior-inferior,SI)和前后(anterior-posterior,AP)方向的位移数值,分析两个区域位移的差异性、相关性,并且计算相对位移,应用公式M_(PTV)=2.5Σ+0.7σ计算PTV外扩边界。结果:盆腔淋巴引流区、前列腺精囊腺在左右、头脚、前后平移方向位移误差分别为LR:(0.27±0.58)mm vs (0.31±0.61)mm;SI:(0.53±0.91)mm vs (0.68±0.98);AP:(2.03±1.86)mm vs (2.79±2.52)mm。头脚、前后方向位移差异有统计学意义(H=4.577、5.035,P<0.05),左右方向为高度相关(r=0.736),头脚方向为中度相关(r=0.542),前后方向为极低度相关(r=0.190)。两个区域在LR、SI和AP的相对位移5 mm的百分比分别为4.9%、5.3%和29.2%。盆腔淋巴引流区LR、SI、AP方向PTV外扩范围分别为1.08 mm、1.96 mm、6.38 mm,前列腺精囊腺LR、SI、AP方向PTV外扩范围为1.20 mm、2.39 mm、8.74 mm。结论:在前列腺癌调强放疗中,盆腔淋巴引流区和前列腺精囊腺靶区在分次治疗间前后方向位移较大,且两区域靶区在前后方向容易发生较大的相对位移,无法通过影像引导校正误差,应尽可能保持膀胱和直肠状态与CT定位时一致。展开更多
基金Supported by grants from the Nanchong City School Cooperation Project(No.18SXHZ0542)Hubei Chen Xiaoping Science and Technology Development Foundation Project(No.CXPJJH11900002-037)Sichuan Medical Research Youth Innovation Project(No.Q18031).
文摘Objective To explore the differences in three different registration methods of cone beam computed tomography(CBCT)-guided down-regulated intense radiation therapy for lung cancer as well as the effects of tumor location,treatment mode,and tumor size on registration.Methods This retrospective analysis included 80 lung cancer patients undergoing radiotherapy in our hospital from November 2017 to October 2019 and compared automatic bone registration,automatic grayscale(t+r)registration,and automatic grayscale(t)positioning error on the X-,Y-,and Z-axes under three types of registration methods.The patients were also grouped according to tumor position,treatment mode,and tumor size to compare positioning errors.Results On the X-,Y-,and Z-axes,automatic grayscale(t+r)and automatic grayscale(t)registration showed a better trend.Analysis of the different treatment modes showed differences in the three registration methods;however,these were not statistically significant.Analysis according to tumor sizes showed significant differences between the three registration methods(P<0.05).Analysis according to tumor positions showed differences in the X-and Y-axes that were not significant(P>0.05),while the autopsy registration in the Z-axis showed the largest difference in the mediastinal and hilar lymph nodes(P<0.05).Conclusion The treatment mode was not the main factor affecting registration error in lung cancer.Three registration methods are available for tumors in the upper and lower lungs measuring<3 cm;among these,automatic gray registration is recommended,while any gray registration method is recommended for tumors located in the mediastinal hilar site measuring<3 cm and in the upper and lower lungs≥3 cm.
文摘Currently the voxel based registration methods have been used widely such as the well known mutual information (MI). Although the accuracy of their results is plausible, the registration procedure is slow. This paper proposed some methods to rigid registration based on mutual information, aiming for an acceleration of the registration process without significantly loss of precision in the final results. The efficiency of these methods is examined by registration of CT MR and PET MR. Experimental results show that the speedup is effective and efficient. By using the fast methods, the registration of 3 D medical image could also be implemented on PC rapidly.
文摘Three characteristic points in the deformation history of a fractured tensile specimen are selected tocalculate two values of n( n1 and n2 ) to represent the hardening ability of material during the homogeneous plas-tic deformation and the following large plastic deformation. Experimental results obtained with mild streel andred copper show that n determined using the three-point method proposed is better to describe the hardening a-bility of material. It is therefore concluded that three-point method can be used to describe the hardening prop-erty of material during both homogeneous deformation and large plastic deformation.
文摘目的:研究iCBCT引导前列腺癌调强放疗中盆腔淋巴引流区和前列腺精囊腺靶区位移的差异性,为临床上选择合理的图像引导策略提供参考依据。方法:回顾性选取2023年01月至2023年09月在中山大学肿瘤防治中心进行调强放疗的21例前列腺癌患者,要求患者在定位及治疗前充盈膀胱、排空直肠,对患者治疗前扫描的iCBCT影像分别以盆腔骨性结构、前列腺精囊腺为参考进行离线配准(自动配准后手动调整),分别评估盆腔淋巴引流区、前列腺精囊腺的靶区位移误差,得到左右(left-right,LR)、头脚(superior-inferior,SI)和前后(anterior-posterior,AP)方向的位移数值,分析两个区域位移的差异性、相关性,并且计算相对位移,应用公式M_(PTV)=2.5Σ+0.7σ计算PTV外扩边界。结果:盆腔淋巴引流区、前列腺精囊腺在左右、头脚、前后平移方向位移误差分别为LR:(0.27±0.58)mm vs (0.31±0.61)mm;SI:(0.53±0.91)mm vs (0.68±0.98);AP:(2.03±1.86)mm vs (2.79±2.52)mm。头脚、前后方向位移差异有统计学意义(H=4.577、5.035,P<0.05),左右方向为高度相关(r=0.736),头脚方向为中度相关(r=0.542),前后方向为极低度相关(r=0.190)。两个区域在LR、SI和AP的相对位移5 mm的百分比分别为4.9%、5.3%和29.2%。盆腔淋巴引流区LR、SI、AP方向PTV外扩范围分别为1.08 mm、1.96 mm、6.38 mm,前列腺精囊腺LR、SI、AP方向PTV外扩范围为1.20 mm、2.39 mm、8.74 mm。结论:在前列腺癌调强放疗中,盆腔淋巴引流区和前列腺精囊腺靶区在分次治疗间前后方向位移较大,且两区域靶区在前后方向容易发生较大的相对位移,无法通过影像引导校正误差,应尽可能保持膀胱和直肠状态与CT定位时一致。
