CT/CT图像融合技术评价食管癌二程放疗的可靠性研究

目的：探讨利用CT/CT图像融合技术来评价食管癌二程放疗的准确性和可靠性。方法：9例食管癌患者,接受调强放疗46Gy后,行二次CT定位,制定后程适形或调强计划,给予处方剂量20Gy。将两次CT图像融合得到全程融合计划,总处方剂量66Gy。比较两个疗程危及器官的体积变化,将首程计划移植到二次定位图像上,计算并比较危及器官受照剂量的差别;将一程计划和二程计划的危及器官评价结果直接相加,与融合计划进行比较。结果：两次定位肺与心脏的体积变化差异无统计学意义（P〉0.05）;CT/CT融合精度对肺和心脏的受量评价差异无统计学意义（P〉0.05）,而对于脊髓最大受照剂量差异具有统计学意义（P〈0.05）;分次计划评价指标相加与融合计划的比较结果是,双侧肺V20、心脏V30的差异有统计学意义（P〈0.05）,双侧肺平均受照剂量和脊髓的最大受照剂量差异无统计学意义（P〉0.05）。结论：在食管癌分程放疗中,宜采用融合计划来评价肺和心脏的受照剂量,可以采用两次计划分别评价得出的脊髓最大受照剂量之和来作为全程脊髓最大受量的评价指标。

Reliability study of CT/CT image fusion in evaluation of two-phase radiotherapy for esophageal carcinoma

Objective：To analyze the accuracy and reliability of CT/CT image fusion in evaluation of two-phase radiotherapy for esophageal carcinoma.Methods：Nine patients with esophageal carcinoma were treated by IMRT.After a dose of 46Gy,they were performed with CT scan again.CRT or IMRT plans were designed with a dose of 20Gy.The two-phase images were fused to the whole course plan at the total dose of 66Gy.The volume of organs at risk（OAR） was compared between two-phase radiotherapy.The original plan was transplanted to the second-time images,and the radiation dose of OAR was compared.The DVH parameters of the original plan plus the second plan were compared with the fusion plan.Results：There was no statistical difference in the volume of lungs and hearts between two phases（P0.05）.There was no statistical difference in the radiation dose of lungs and hearts after CT/CT fusion（P0.05）,but there was statistical difference in the maximal dose to spinal cord（P0.05）.There was statistical difference in V20 to all lungs,V30 to heart between the original plan plus the second plan and the fusion plan（P0.05）,but there was no statistical difference in the mean dose to all lungs,the maximal dose to spinal cord（P0.05）.Conclusion： During two-phase radiotherapy for esophageal carcinoma,the radiation dose of lung and heart should be evaluated by the fusion plan,and the whole course maximum dose of spinal cord should be the sum of respective the maximum dose of two phase plans.