目的：比较4DCT呼吸周期八分法、四分法与传统十分法重建模式对肺孤立灶靶区构建的影响，探讨八分法、四分法在4DCT模拟定位中的可行性。方法24例肺孤立灶行4DCT扫描，按3种呼吸周期均分法进行图像重建及ITV构建，比较ITV10、ITV8、ITV...目的：比较4DCT呼吸周期八分法、四分法与传统十分法重建模式对肺孤立灶靶区构建的影响，探讨八分法、四分法在4DCT模拟定位中的可行性。方法24例肺孤立灶行4DCT扫描，按3种呼吸周期均分法进行图像重建及ITV构建，比较ITV10、ITV8、ITV4大小和中心点位置及三维方向运动度。 Friedman M 法非参数检验差异。结果 ITV10、ITV8、ITV4大小分别为（9．09±12.29）、（9．10±12.47）、（8．98±12.61） cm3（P＝0.001），ITV10与ITV8相近（P＝0.721），ITV10与ITV4不同（P＝0.002）。 ITV10、ITV8、ITV4中心点坐标分别为x轴（12．22±7.71）、（12．23±7.71）、（12．22±7.71）（P＝0.668）；y轴：（43．30±29.38）、（43．30±29.40）、（43．31±29.39）（P＝0.643）；z轴：（5．66±3.67）、（5．66±3.67）、（5．66±3.67）（P＝0.878）。3种重建模式下肿瘤中心在三维方向的运动度分别为x轴：（0．69±0.56）、（0．69±0.68）、（0．79±0.51） mm （P＝0.356）；y轴：（3．13±3.78）、（3．13±4.05）、（3．19±4.06） mm （P＝0.978）；z轴：（1．18±1.31）、（1．03±1.32）、（1．16±1.34） mm （P＝0.302）。结论肺孤立灶4DCT模拟定位呼吸周期八分法与十分法重建模式下ITV大小、中心点位置及三维方向的运动度均相近，八分法减少了重建图像的数量和靶区勾画负荷，在4DCT模拟定位中具有可行性。展开更多
Purpose: To investigate the feasibility of partial arc volumetric modulated arc therapy (VMAT) in lung cancer stereotactic body radiotherapy (SBRT), as well the volumetric and dosimetric effects of different internal ...Purpose: To investigate the feasibility of partial arc volumetric modulated arc therapy (VMAT) in lung cancer stereotactic body radiotherapy (SBRT), as well the volumetric and dosimetric effects of different internal target volume (ITV) definitions with 4D CT. Methods: Fourteen patients with primary and metastatic lung cancer underwent SBRT were enrolled. Full and partial arc VMAT plans were generated with four different ITVs: ITVall, ITVMIP, ITVAIP and ITV2phases, representing ITVs generated from all 10 respiratory phases, maximum intensity projection (MIP), average intensity projection (AIP), and 2 extreme respiratory phases. Volumetric and dosimetric differences, as well as MU and delivery time were investigated. Results: Partial arc VMAT irradiated more dose at 2 cm away from planning target volume (PTV) (P = 0.002), however, it achieved better protection on mean lung dose , lung V5, spinal cord, heart and esophagus compared with full arc VMAT. The average MU and delivery time of partial arc VMAT were 240 and 1.6 min less than those of full arc VMAT. There were no significant differences on target coverage and organ at risks (OARs) sparing among four ITVs. The average percent volume differences of ITVMIP, ITVAIP and ITV2phases to ITVall were 8.6%, 13.4%, and 25.2%, respectively. Conclusions: Although partial arc VMAT delivered more dose 2 cm out of PTV, it decreases the dose to lung, spinal cord, and esophagus, as well decreased the total MU and delivery time compared with full arc VMAT without sacrificing target coverage. Partial arc VMAT was feasible and more efficient for lung SBRT.展开更多
文摘目的：比较4DCT呼吸周期八分法、四分法与传统十分法重建模式对肺孤立灶靶区构建的影响，探讨八分法、四分法在4DCT模拟定位中的可行性。方法24例肺孤立灶行4DCT扫描，按3种呼吸周期均分法进行图像重建及ITV构建，比较ITV10、ITV8、ITV4大小和中心点位置及三维方向运动度。 Friedman M 法非参数检验差异。结果 ITV10、ITV8、ITV4大小分别为（9．09±12.29）、（9．10±12.47）、（8．98±12.61） cm3（P＝0.001），ITV10与ITV8相近（P＝0.721），ITV10与ITV4不同（P＝0.002）。 ITV10、ITV8、ITV4中心点坐标分别为x轴（12．22±7.71）、（12．23±7.71）、（12．22±7.71）（P＝0.668）；y轴：（43．30±29.38）、（43．30±29.40）、（43．31±29.39）（P＝0.643）；z轴：（5．66±3.67）、（5．66±3.67）、（5．66±3.67）（P＝0.878）。3种重建模式下肿瘤中心在三维方向的运动度分别为x轴：（0．69±0.56）、（0．69±0.68）、（0．79±0.51） mm （P＝0.356）；y轴：（3．13±3.78）、（3．13±4.05）、（3．19±4.06） mm （P＝0.978）；z轴：（1．18±1.31）、（1．03±1.32）、（1．16±1.34） mm （P＝0.302）。结论肺孤立灶4DCT模拟定位呼吸周期八分法与十分法重建模式下ITV大小、中心点位置及三维方向的运动度均相近，八分法减少了重建图像的数量和靶区勾画负荷，在4DCT模拟定位中具有可行性。
文摘Purpose: To investigate the feasibility of partial arc volumetric modulated arc therapy (VMAT) in lung cancer stereotactic body radiotherapy (SBRT), as well the volumetric and dosimetric effects of different internal target volume (ITV) definitions with 4D CT. Methods: Fourteen patients with primary and metastatic lung cancer underwent SBRT were enrolled. Full and partial arc VMAT plans were generated with four different ITVs: ITVall, ITVMIP, ITVAIP and ITV2phases, representing ITVs generated from all 10 respiratory phases, maximum intensity projection (MIP), average intensity projection (AIP), and 2 extreme respiratory phases. Volumetric and dosimetric differences, as well as MU and delivery time were investigated. Results: Partial arc VMAT irradiated more dose at 2 cm away from planning target volume (PTV) (P = 0.002), however, it achieved better protection on mean lung dose , lung V5, spinal cord, heart and esophagus compared with full arc VMAT. The average MU and delivery time of partial arc VMAT were 240 and 1.6 min less than those of full arc VMAT. There were no significant differences on target coverage and organ at risks (OARs) sparing among four ITVs. The average percent volume differences of ITVMIP, ITVAIP and ITV2phases to ITVall were 8.6%, 13.4%, and 25.2%, respectively. Conclusions: Although partial arc VMAT delivered more dose 2 cm out of PTV, it decreases the dose to lung, spinal cord, and esophagus, as well decreased the total MU and delivery time compared with full arc VMAT without sacrificing target coverage. Partial arc VMAT was feasible and more efficient for lung SBRT.
