4DCT在肺癌放射治疗中的应用及剂量学研究
发布时间：2019-06-05 17:09
【摘要】：目前，肺癌放射治疗通常采用螺旋CT在患者自由呼吸状态下行定位扫描，每层扫描时间远小于一个呼吸周期所需时间，由此所采集到的图像只是肿瘤在某一呼吸周期中一个随机时相点的影像，既不能反映肿瘤在静止状态下的情况，也不能准确反映肿瘤在呼吸周期中的运动范围。由此图像进行计划设计，不但增大了正常组织的受量，同时也增加了肿瘤漏照的可能。 本论文对30例肺癌患者同时采用统一体位固定装置行常规CT扫描与4DCT扫描，对所得到的的图像按照ICRU62号报告规定进行以下处理：对常规CT定位图像进行GTV的勾画；在4DCT10各呼吸时相图像上分别勾画取平均值IGTV，用4DCT图像中的最大密度投影图像进行GTVMIP勾画；用平静呼气末时相和平静吸气末时相的融合图像进行GTV0+50勾画，按照不同的外放形成PTV后进行计划设计，将此计划投影到4DCT各时相上去，，进行剂量学分析。同时，对基于最大密度投影图像和平静呼气末时相和平静吸气末时相的融合图像所设计的和资料计划进行剂量学比较。 体积比较显示：GTV与IGTV比较无统计学差异，GTVMIP和GTV0+50与IGTV比较均有统计学差异，GTVMIP和GTV0+50比较无统计学差异。 剂量学比较显示：基于常规CT的治疗计划对上肺癌患无统计学差异，中下肺均有统计学差异；基于MIP的治疗计划和基于双时相融合图像的治疗计划对所有肺癌患者均有统计学差异。所有的治疗计划对全肺剂量学比较均有统计学差异。 应用4DCT进行肺癌的放射治疗，在不增加正常组织受量的前提下，提高靶区覆盖率，可以获得更好的局部控制率。
[Abstract]:At present, radiotherapy for lung cancer usually uses spiral CT to localize the patient's free breathing state, and the scanning time per layer is much less than that required for a respiratory cycle. The obtained images are only a random time-point image of the tumor in a certain respiratory cycle, which can neither reflect the static state of the tumor nor accurately reflect the range of motion of the tumor in the respiratory cycle. The planning of the image not only increases the amount of normal tissue, but also increases the possibility of tumor leakage. In this paper, 30 patients with lung cancer were scanned by conventional CT scanning and 4DCT scanning with unified posture fixation device at the same time. According to the ICRU62 report, the obtained images were processed as follows: the conventional CT localization images were sketched by GTV; The average value of IGTV, was sketched on the images of each breathing phase of 4DCT10, and the maximum density projection image of 4DCT image was used for GTVMIP sketching. The fusion images of calm end-breath phase and calm inspiratory end-phase were used to sketch GTV0 50. After PTV was formed according to different explants, the plan was projected to each phase of 4DCT, and dosimetric analysis was carried out. At the same time, the dosimetric comparison of the fusion images based on the maximum density projection image and the calm end-breath phase and the calm end-inspiratory phase was carried out. The volume comparison showed that there was no significant difference between GTV and IGTV, GTVMIP and GTV0 50 were statistically different from IGTV, but there was no significant difference between GTVMIP and GTV0 50. The dosimetric comparison showed that there was no significant difference in the treatment plan based on conventional CT for patients with upper lung cancer, but there was significant difference between the middle and lower lungs. There were significant differences between MIP-based treatment plan and dual-phase fusion image-based treatment plan for all patients with lung cancer. All treatment plans were statistically different in whole lung dosimetry. The radiotherapy of lung cancer with 4DCT can obtain better local control rate by increasing the coverage of target area without increasing the amount of normal tissue.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R734.2;R730.55
本文编号：2493685
[Abstract]:At present, radiotherapy for lung cancer usually uses spiral CT to localize the patient's free breathing state, and the scanning time per layer is much less than that required for a respiratory cycle. The obtained images are only a random time-point image of the tumor in a certain respiratory cycle, which can neither reflect the static state of the tumor nor accurately reflect the range of motion of the tumor in the respiratory cycle. The planning of the image not only increases the amount of normal tissue, but also increases the possibility of tumor leakage. In this paper, 30 patients with lung cancer were scanned by conventional CT scanning and 4DCT scanning with unified posture fixation device at the same time. According to the ICRU62 report, the obtained images were processed as follows: the conventional CT localization images were sketched by GTV; The average value of IGTV, was sketched on the images of each breathing phase of 4DCT10, and the maximum density projection image of 4DCT image was used for GTVMIP sketching. The fusion images of calm end-breath phase and calm inspiratory end-phase were used to sketch GTV0 50. After PTV was formed according to different explants, the plan was projected to each phase of 4DCT, and dosimetric analysis was carried out. At the same time, the dosimetric comparison of the fusion images based on the maximum density projection image and the calm end-breath phase and the calm end-inspiratory phase was carried out. The volume comparison showed that there was no significant difference between GTV and IGTV, GTVMIP and GTV0 50 were statistically different from IGTV, but there was no significant difference between GTVMIP and GTV0 50. The dosimetric comparison showed that there was no significant difference in the treatment plan based on conventional CT for patients with upper lung cancer, but there was significant difference between the middle and lower lungs. There were significant differences between MIP-based treatment plan and dual-phase fusion image-based treatment plan for all patients with lung cancer. All treatment plans were statistically different in whole lung dosimetry. The radiotherapy of lung cancer with 4DCT can obtain better local control rate by increasing the coverage of target area without increasing the amount of normal tissue.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R734.2;R730.55
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