| Wang Jinzhi,Li Jianbin,Wang Wei,Zhang Yingjie,Ding Yun,Liu Tonghai,Shang Dongping.Variations of the spatial position and overlap ratio for primary thoracic esophageal cancer target during radiotherapy based on four-dimensional CT scans[J].Chinese Journal of Radiological Medicine and Protection,2014,34(8):592-596 |
| Variations of the spatial position and overlap ratio for primary thoracic esophageal cancer target during radiotherapy based on four-dimensional CT scans |
| Received:October 31, 2013 |
| DOI：10.3760/cma.j.issn.0254-5098.2014.08.008 |
| KeyWords:Esophageal neoplasm/radiotherapy Tomography, X ray computed, four-dimensional Tumor volume Degree of inclusion Matching index |
| FundProject:山东省科技发展计划项目（2011YD18039）；山东省科技发展计划项目（2011YD18082） |
| Author Name | Affiliation | E-mail | | Wang Jinzhi | Department of Radiation Oncology, Shandong Cancer Hospital, Medicine and Life Sciences College of Shandong Academy of Medical Sciences, Jinan University, Jinan 250117, China | | | Li Jianbin | Department of Radiation Oncology, Shandong Cancer Hospital, Medicine and Life Sciences College of Shandong Academy of Medical Sciences, Jinan University, Jinan 250117, China | lijianbin@msn.com | | Wang Wei | Department of Radiation Oncology, Shandong Cancer Hospital, Medicine and Life Sciences College of Shandong Academy of Medical Sciences, Jinan University, Jinan 250117, China | | | Zhang Yingjie | Department of Radiation Oncology, Shandong Cancer Hospital, Medicine and Life Sciences College of Shandong Academy of Medical Sciences, Jinan University, Jinan 250117, China | | | Ding Yun | Department of Radiation Oncology, Shandong Cancer Hospital, Medicine and Life Sciences College of Shandong Academy of Medical Sciences, Jinan University, Jinan 250117, China | | | Liu Tonghai | Department of Radiation Oncology, Shandong Cancer Hospital, Medicine and Life Sciences College of Shandong Academy of Medical Sciences, Jinan University, Jinan 250117, China | | | Shang Dongping | Department of Radiation Oncology, Shandong Cancer Hospital, Medicine and Life Sciences College of Shandong Academy of Medical Sciences, Jinan University, Jinan 250117, China | |
|
| Hits: 3021 |
| Download times: 1943 |
| Abstract:: |
| Objective To investigate the variations of the spatial position and overlap ratio of the internal target volume (ITV) and planning target volume (PTV) of primary thoracic esophagus carcinoma using repeated four-dimensional computed tomography (4D-CT) scanning during conventional fractionated radiotherapy. Methods Thirty patients with thoracic esophageal carcinoma were included whose 4D-CT scans were conducted before radiotherapy and between every ten fractions. The gross tumor volumes (GTVs) were delineated by the same radiation oncologist on each 4D-CT image phase, and the ITV and PTV were constructed afterwards. Results No significant difference of the isocenters was observed for the ITV and PTV during the treatment course, yet both the volumes of the ITV and PTV decreased. The median DI (the degree of inclusion) of the target acquired subsequently in the original target were 0.85,0.77 (Z=-3.10, P<0.05) for ITV and 0.86、0.82(Z=-2.49, P<0.05)for PTV respectively during entire treatment. The variation of volume ratio correlated strongly with the variation of DI (the DI of the target acquired subsequent in the original target) (rITV=0.71, rPTV=0.77, P<0.05). The variation of volume ratio and the variation of the matching index (MI) were positively correlated (rITV=0.47, rPTV=0.59, P<0.05). The 3D vectors of ITV and PTV motions were negatively correlated with the corresponding MI (rITV=-0.52, rPTV=-0.36, P<0.05). If the initial PTV was used for treatment planning, 8.80% and 6.37% of the target volume would be missed at the tenth and twentieth fraction (Z=-0.55, P>0.05), respectively. In the meanwhile, 11.45% and 18.49% of the normal tissues would be wrongly irradiated at the corresponding time points (Z=-2.49,P<0.05). Conclusions The variations of the spatial position of all targets were all less than 0.6 cm. The DI and the MI of the target decrease by various degrees during the treatment course, which lead to target mispositioning and normal tissue irradiation at different levels. |
| HTML View Full Text View/Add Comment Download reader |
| Close |
|
|
|
