基于扫描部位特征的低剂量CT扫描参数优化临床研究

发布时间：2018-03-05 05:08

本文选题：体层摄影术　切入点：X线计算机　出处：《天津大学》2012年硕士论文　论文类型：学位论文

【摘要】：CT低剂量参数优化的研究,近些年来一直是大家关注的热点不同的领域从如何设计及优化CT低剂量扫描方案重建算法等方面进行探索，使受检者在接受较低辐射剂量的同时获得较好的有足够诊断信息的图像本课题研究旨在通过实验得到不同人体扫描部位CT低剂量扫描最优曝光参数，降低辐射剂量，为影像技师提供合理的扫描参数针对目前CT低剂量的研究多集中在改变扫描参数上，本研究引入体型因素作为修正，选择与图像质量相关性最大的体厚周径元素，依据受检者体厚周径的不同，设定扫描参数，并与常规参数的图像质量及辐射剂量对比，以探讨在图像满足临床诊断的同时，体厚周径指导降低CT扫描剂量的可行性，最终得出临床实际应用的合理参数本研究首先对QA模体进行不同KV mAs的扫描，分析图像质量评价参数包括密度分辨率空间分辨率均匀性及噪声，在其符合中华人民共和国国家计量检定规程中的医用诊断螺旋计算机断层摄影装置（CT）X射线辐射源检定规程，即文件JJG1026一2007要求的前提下，筛选出合理的低剂量扫描参数然后对不同体厚的头胸腹各270例受检者行低剂量参数扫描，通过对低剂量扫描图像的对比评价及噪声的定量测量，在图像具有一定的密度分辨率空间分辨率均匀性及适度噪声满足临床诊断的前提下，得出不同体厚受检者最优扫描参数，使得辐射剂量最低最后将最优参数应用于病例组，头胸腹各60例患者，与常规扫描参数进行比较，进一步验证并修正扫描参数，应用于临床研究表明对受检者进行体型分类后行低剂量扫描与之前所有患者均采用统一常规剂量扫描的方法比较，在不降低图像诊断结果的情况下，总体扫描剂量有大幅降低，头胸腹平均扫描剂量降低分别约为28%39%27%患者的受照剂量趋于合理化，，达到了图像质量与射线剂量的均衡，具有良好的社会效益
[Abstract]:In recent years, the research on the optimization of low dose CT parameters has been a hot topic in different fields, such as how to design and optimize the reconstruction algorithm of low dose CT scanning schemes, and so on. The purpose of this study is to get optimal exposure parameters of CT low dose scanning in different human body scanning sites through experiments, and to reduce radiation dose. Provide reasonable scanning parameters for image technician. In view of the current research of CT low dose is focused on changing the scanning parameters, this study introduces the body shape factor as a correction, and selects the body thickness circumference element, which has the greatest correlation with image quality, according to the difference of the body thickness circumference of the subject. The scanning parameters are set, and compared with the image quality and radiation dose of conventional parameters, so as to discuss the feasibility of reducing CT scanning dose under the guidance of body thickness circumference while the image meets the clinical diagnosis. Finally, the reasonable parameters for clinical application are obtained. In this study, the QA motifs were scanned with different KV mAs, and the image quality evaluation parameters including density resolution spatial resolution uniformity and noise were analyzed. In accordance with the verification regulation of the medical diagnostic helical computed tomography equipment of the people's Republic of China in the national metrological verification regulation, namely, the document JJG1026-2007, The reasonable low dose scanning parameters were screened, and 270 cases of head, chest and abdomen with different body thickness were scanned with low dose parameters. The contrast evaluation of low dose scanning images and the quantitative measurement of noise were carried out. Under the premise that the image has a certain spatial resolution uniformity of density resolution and moderate noise to satisfy the clinical diagnosis, the optimal scanning parameters of the patients with different body thickness are obtained, so that the optimal parameters are applied to the case group at the end of the radiation dose. 60 patients with head, chest and abdomen were compared with the conventional scanning parameters. The parameters were further verified and modified, and applied to clinical practice. The study showed that the total scanning dose was significantly reduced without lowering the diagnostic results of the image, compared with that of all the previous patients using the unified routine dose scanning method after the classification of the body types of the subjects. The average scanning dose of head, chest and abdomen decreased by about 289% of the patients respectively, and the radiation dose tended to be rationalized, which achieved the balance between the image quality and the dose of radiation, and had good social benefit.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R814.42

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