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Abstract：
OBJECTIVE: Respiratory movement has an important impact on the radiotherapy for lung tumor. Respiratory gating technology is helpful to improve the accuracy of target delineation. This study investigated the value of prospective and retrospective respiratory gating simulations in target delineation and radiotherapy plan design for solitary pulmonary tumors (SPTs) in radiotherapy.
METHODS: The enrolled patients underwent CT simulation with three-dimensional (3D) CT non gating, prospective respiratory gating, and retrospective respiratory gating simulation. The target volumes were delineated on three sets of CT images, and radiotherapy plans were prepared accordingly. Tumor displacements and movement information obtained using the two respiratory gating approaches, as well as the target volumes and dosimetry parameters in the radiotherapy plan were compared.
RESULTS: No significant difference was observed in tumor displacement measured using the two gating methods (p > 0.05). However, the internal gross tumor volumes (IGTVs), internal target volumes (ITVs), and planning target volumes (PTVs) based on the retrospective respiratory gating simulation were larger than those obtained using prospective gating (group A: pIGTV = 0.041, pITV = 0.003, pPTV = 0.008; group B: pIGTV = 0.025, pITV = 0.039, pPTV = 0.004). The two-gating PTVs were both smaller than those delineated on 3D non gating images (p < 0.001). V5Gy, V10Gy, V20Gy, V30Gy, and mean lung dose in the two gated radiotherapy plans were lower than those in the 3D non gating plan (p < 0.001); however, no significant difference was observed between the two gating plans (p > 0.05).
CONCLUSIONS: The application of respiratory gating could reduce the target volume and the radiation dose that the normal lung tissue received. Compared to prospective respiratory gating, the retrospective gating provides more information about tumor movement in PTV.
METHODS: The enrolled patients underwent CT simulation with three-dimensional (3D) CT non gating, prospective respiratory gating, and retrospective respiratory gating simulation. The target volumes were delineated on three sets of CT images, and radiotherapy plans were prepared accordingly. Tumor displacements and movement information obtained using the two respiratory gating approaches, as well as the target volumes and dosimetry parameters in the radiotherapy plan were compared.
RESULTS: No significant difference was observed in tumor displacement measured using the two gating methods (p > 0.05). However, the internal gross tumor volumes (IGTVs), internal target volumes (ITVs), and planning target volumes (PTVs) based on the retrospective respiratory gating simulation were larger than those obtained using prospective gating (group A: pIGTV = 0.041, pITV = 0.003, pPTV = 0.008; group B: pIGTV = 0.025, pITV = 0.039, pPTV = 0.004). The two-gating PTVs were both smaller than those delineated on 3D non gating images (p < 0.001). V5Gy, V10Gy, V20Gy, V30Gy, and mean lung dose in the two gated radiotherapy plans were lower than those in the 3D non gating plan (p < 0.001); however, no significant difference was observed between the two gating plans (p > 0.05).
CONCLUSIONS: The application of respiratory gating could reduce the target volume and the radiation dose that the normal lung tissue received. Compared to prospective respiratory gating, the retrospective gating provides more information about tumor movement in PTV.
摘要：
目的：呼吸运动对肺部肿瘤的放疗有重要影响。呼吸门控技术有助于提高目标描绘的准确性。这项研究调查了前瞻性和回顾性呼吸门控模拟在放射治疗中孤立性肺肿瘤（SPT）的目标描绘和放射治疗计划设计中的价值。
方法：入选患者接受了三维（3D）CT无门CT模拟，前瞻性呼吸门控，和回顾性呼吸门控模拟。在三组CT图像上描绘了目标体积，并据此编制放疗计划。使用两种呼吸门控方法获得的肿瘤位移和移动信息，以及放疗计划中的靶区体积和剂量学参数进行了比较。
结果：在使用两种门控方法测量的肿瘤位移中未观察到显着差异（p>0.05）。然而,内部总肿瘤体积(IGTV)，内部目标体积(ITV)，和基于回顾性呼吸门控模拟的计划目标体积(PTV)大于使用前瞻性门控获得的目标体积(A组:pIGTV=0.041,pITV=0.003,pPTV=0.008;B组:pIGTV=0.025,pITV=0.039,pPTV=0.004).双门控PTV均小于在3D非门控图像上描绘的那些(p<0.001)。V5Gy,V10Gy,V20Gy,V30Gy,两种门控放疗计划的平均肺剂量均低于3D非门控计划(p<0.001);两种门控方案之间无显著差异(p>0.05)。
结论：应用呼吸门控可以降低靶体积和正常肺组织接受的辐射剂量。与前瞻性呼吸门控相比，回顾性门控提供了关于PTV中肿瘤运动的更多信息.
方法：入选患者接受了三维（3D）CT无门CT模拟，前瞻性呼吸门控，和回顾性呼吸门控模拟。在三组CT图像上描绘了目标体积，并据此编制放疗计划。使用两种呼吸门控方法获得的肿瘤位移和移动信息，以及放疗计划中的靶区体积和剂量学参数进行了比较。
结果：在使用两种门控方法测量的肿瘤位移中未观察到显着差异（p>0.05）。然而,内部总肿瘤体积(IGTV)，内部目标体积(ITV)，和基于回顾性呼吸门控模拟的计划目标体积(PTV)大于使用前瞻性门控获得的目标体积(A组:pIGTV=0.041,pITV=0.003,pPTV=0.008;B组:pIGTV=0.025,pITV=0.039,pPTV=0.004).双门控PTV均小于在3D非门控图像上描绘的那些(p<0.001)。V5Gy,V10Gy,V20Gy,V30Gy,两种门控放疗计划的平均肺剂量均低于3D非门控计划(p<0.001);两种门控方案之间无显著差异(p>0.05)。
结论：应用呼吸门控可以降低靶体积和正常肺组织接受的辐射剂量。与前瞻性呼吸门控相比，回顾性门控提供了关于PTV中肿瘤运动的更多信息.
