用于计算机断层扫描中剂量降低的铅制乳房屏蔽物的特性描述
Characterization of a lead breast shielding for dose reduction in computed tomography.
作者信息
Correia Paula Duarte, Granzotti Cristiano Roberto Fabri, Santos Yago da Silva, Brochi Marco Aurelio Corte, de Azevedo-Marques Paulo Mazzoncini
机构信息
Bachelor degree, Fellow Master degree in Medicine - Area of Investigation in Medical Practice - Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Ribeirão Preto, SP, Brazil.
Bachelor degree, Student of the Program for Mastership and Doctorate in Physics Applied to Medicine and Biology (FAMB), Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto da Universidade de São Paulo (FFCLRP-USP), Ribeirão Preto, SP, Brazil.
出版信息
Radiol Bras. 2014 Jul-Aug;47(4):223-7. doi: 10.1590/0100-3984.2013.1861.
OBJECTIVE
Several studies have been published regarding the use of bismuth shielding to protect the breast in computed tomography (CT) scans and, up to the writing of this article, only one publication about barium shielding was found. The present study was aimed at characterizing, for the first time, a lead breast shielding.
MATERIALS AND METHODS
The percentage dose reduction and the influence of the shielding on quantitative imaging parameters were evaluated. Dose measurements were made on a CT equipment with the aid of specific phantoms and radiation detectors. A processing software assisted in the qualitative analysis evaluating variations in average CT number and noise on images.
RESULTS
The authors observed a reduction in entrance dose by 30% and in CTDIvol by 17%. In all measurements, in agreement with studies in the literature, the utilization of cotton fiber as spacer object reduced significantly the presence of artifacts on the images. All the measurements demonstrated increase in the average CT number and noise on the images with the presence of the shielding.
CONCLUSION
As expected, the data observed with the use of lead shielding were of the same order as those found in the literature about bismuth shielding.
目的
关于在计算机断层扫描（CT）中使用铋屏蔽来保护乳房，已经发表了多项研究，截至本文撰写时，仅发现一篇关于钡屏蔽的出版物。本研究旨在首次对铅制乳房屏蔽进行特性描述。
材料与方法
评估了屏蔽对剂量的降低百分比以及对定量成像参数的影响。借助特定体模和辐射探测器在CT设备上进行剂量测量。一款处理软件协助进行定性分析，评估图像上平均CT值和噪声的变化。
结果
作者观察到入射剂量降低了30%，容积CT剂量指数（CTDIvol）降低了17%。在所有测量中，与文献中的研究一致，使用棉纤维作为间隔物显著减少了图像上伪影的出现。所有测量均表明，有屏蔽时图像上的平均CT值和噪声增加。
结论
正如预期的那样，使用铅屏蔽观察到的数据与文献中关于铋屏蔽的数据处于同一量级。
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