常见类型医用X射线摄影的剂量指导水平研究

发布时间：2018-07-11 16:15

本文选题：医疗照射 + X射线摄影　；参考：《复旦大学》2013年硕士论文

【摘要】：[研究目的]医疗照射是人工电离辐射的最大来源,人类在对X射线积极开发利用时,发现它是一把双刃剑,我们要注意其辐射防护问题。适时掌握医用X射线诊断所致受检者剂量水平现状和变化情况,可以为制订医用X射线诊断的剂量参考(指导)水平(DRL)及其相应辐射防护措施提供依据。常规方法的剂量水平普查准确但耗时费力,而利用剂量估算模式开展剂量水平调查存在有一定的不确定度但相对便捷。我国十年来未更新指导水平,且各地区未根据本地实际制订本地参考水平。本研究旨在通过实际调查和模式估算两种方式得到剂量指导水平,借鉴国外经验,制订出上海市常见三种类型医用X射线摄影的剂量指导水平,并为相关研究提供方法和依据。 [研究方法]为实现上述主要目的,本论文从以下三个方面开展研究：1)通过分析上海市的医疗照射应用频率及其发展趋势,获取当前医用X射线摄影诊断的主要类型；在严格控制数据质量的基础上,用热释光剂量计(TLD)开展三种摄影(胸部正位、胸部侧位和腰椎侧位)共1726名成年受检者的入射体表剂量(ESD)测量；2)基于课题组已经开发的剂量估算模式,先通过实验调查验证,比较实测ESD值和估算ESD值间的差异；再将估算模式应用于本研究的调查中计算得到剂量,并对估算结果进行分析；评定估算模式的不确定度；3)基于剂量指导水平建立方法,结合国内外指导水平的建立现状和发展趋势,将实际调查和模式估算两种方法获取的剂量进一步推导得到剂量指导水平,进行结果分析和比较：根据本地实际,尝试建立上海市三种常见类型医用X射线摄影的剂量指导水平。 [研究结果]上海市医用X射线摄影的应用频率和单次剂量调查结果表明,胸部正位、胸部侧位、腰椎侧位为三个常见或主要类型。本次调查结果显示,上海市这三种类型X射线摄影所致1726名成年受检者的ESD差别较大,三者的ESD均值分别为0.23mGy,0.57mGy,4.48mGy；入射体表剂量值和主要曝光参数(kVp和mAs)的变化趋势与国外同类调查的结果相似。验证实验结果表明,利用剂量估算模式求得这三种类型摄影的ESD与实测结果的相对误差分别为1.9%,5.1%和1.7%,说明了可用该估算模式开展剂量水平的评估。对于全市而言,三种类型摄影所致受检者的入射体表剂量估算值与实测值的均值相差分别为13.0%,12.3%,3.3%,配对t检验显示差异无统计学意义。不同国家或地区DRL的制订时间和类别有一定的差异,但DRL的变化均呈现出下降的趋势。上海市这三种类型X射线诊断在各个设备间所致受检者入射体表剂量均值的75%分位值分别为0.32mGy,0.75mGy和6.84mGy与0.28mGy,0.81mGy,6.92mGy,均小于我国当前推荐的剂量指导水平。 [研究结论]本课题组建立的剂量估算模式可用于医用X射线诊断所致受检者入射体表剂量水平的评估。医用X射线诊断所致受检者剂量在不断降低,建议可将胸部正位、胸部侧位、腰椎侧位摄影诊断剂量指导水平分别设定为0.30mGy,1.0mGy和8.0mGy。
[Abstract]:[Objective] medical irradiation is the largest source of artificial ionizing radiation. When human beings are actively developing and utilizing X rays, it is found that it is a double-edged sword. We should pay attention to the problem of radiation protection. Timely grasp the current situation and changes of the dose level of the examiner caused by medical X ray diagnosis can be a reference for the formulation of the dose of medical X ray diagnosis ( Guidance) level (DRL) and corresponding radiation protection measures provide the basis. The general survey of the dose level of the conventional methods is accurate but time-consuming, but it has some uncertainty but relatively convenient to use the dose estimation model to carry out the dose level survey. In China, the water leveling has not been updated in ten years, and the local reference has not been formulated in various regions according to the local reality. The purpose of this study is to obtain dose guidance level by two ways of actual investigation and model estimation, and draw lessons from foreign experience to draw up the dose guidance level of three types of medical X ray photography common in Shanghai, and provide methods and basis for related research.
[research methods] in order to achieve the above main purpose, this paper carries out the following three aspects: 1) to obtain the main types of medical X ray photography diagnosis by analyzing the frequency of medical irradiation application and its development trend in Shanghai. On the basis of strictly controlling the quality of data, three kinds of photography (chest radiography) are carried out with the thermoluminescence dosimeter (TLD). The incident body surface dose (ESD) measurements of 1726 adult subjects were measured in the Department, the chest side and the lumbar side. 2) based on the dose estimation model developed by the project group, the difference between the measured ESD value and the estimated ESD value was compared with the experimental investigation, and the estimated model formula was used to calculate the dose in the study. The estimation results are analyzed; the uncertainty of evaluation model; 3) based on the method of setting up the dose guidance level, combined with the present situation and development trend of the guidance level at home and abroad, the dose obtained by the actual survey and model estimation is further derived to obtain the level of the dose finger guide, and the results are analyzed and compared. In fact, we try to establish the dose guidance level of three common types of medical X - ray radiography in Shanghai.
[results] the application frequency and single dose survey of medical X ray photography in Shanghai showed that the chest position, the chest lateral position and the lumbar lateral position were three common or main types. The results of this survey showed that the 1726 adult subjects of the three types of X ray photography in the city of Shanghai were different in ESD, and the mean of the three was 0.2, respectively. 3mGy, 0.57mGy, 4.48mGy; the variation trend of the incident body surface dose value and the main exposure parameters (kVp and mAs) is similar to the result of the similar survey in foreign countries. The experimental results show that the relative error between the ESD and the measured results of these three types of photography by using the dose estimation model is 1.9%, 5.1% and 1.7%, indicating that the model can be opened. The assessment of the level of spread dose. For the whole city, the difference between the estimated value of the incident body surface dose and the measured value of the three types of photographers was 13%, 12.3%, 3.3% respectively. The paired t test showed that there was no statistical difference. The time and category of DRL in different countries and regions were different, but the changes of DRL were all present. The downward trend. The three types of X - ray diagnosis in Shanghai were 0.32mGy, 0.75mGy and 6.84mGy with 0.28mGy, 0.81mGy, 6.92mGy, respectively, which were less than the recommended dose level in our country.
[Conclusion] the dose estimation model established by our group can be used to evaluate the level of incidence of incident body surface in the patients with medical X ray diagnosis. The dose of the subjects who are diagnosed with medical X ray is decreasing continuously. It is suggested that the dose guidance of chest position, chest lateral position and lumbar lateral position can be set to 0.30mGy, 1.0mGy and 8 respectively. .0mGy.
【学位授予单位】：复旦大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R814.2

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