计算机断层扫描中空气比释动能指数的测量：方法学比较。

Measurements of air kerma index in computed tomography: A comparison among methodologies.

作者信息

Alonso Thêssa C, Mourão Filho Arnaldo P, Da Silva Teógenes A

机构信息

Program of Nuclear Science and Techniques - Federal University of Minas Gerais, UFMG, Av. Pres. Antônio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, MG, Brazil; Centro de Desenvolvimento da Tecnologia Nuclear, CDTN, Av. Pres. Antônio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, MG, Brazil.

Program of Nuclear Science and Techniques - Federal University of Minas Gerais, UFMG, Av. Pres. Antônio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, MG, Brazil; Federal Centre of Technological Education of Minas Gerais, CEFET-MG, Belo Horizonte, MG, Brazil.

出版信息

Appl Radiat Isot. 2018 Aug;138:10-13. doi: 10.1016/j.apradiso.2017.10.008. Epub 2017 Oct 5.

DOI:10.1016/j.apradiso.2017.10.008

PMID:29033210

Abstract

As CT exams impart high doses to patients in comparison to other radiologist techniques, reliable dosimetry is required. In this work, dosimetry in CT beams was carried out in terms of air kerma index in air or in a phantom measured by a pencil ionization chamber, thermoluminescent (TL) detectors and radiochromic film. Calibration results showed the low energy dependence of all three dosimetric systems for the 100-120kV range, the very high uncertainty of the TL dosimeters in comparison to the other systems and high nonlinearity response in terms of air kerma of the radiochromic film. Measurements with the three systems in a 120kV CT protocol showed an acceptable agreement among the weighted air kerma index values, but TL dosimeters presented the highest uncertainties in the values.

摘要

与其他放射学技术相比，CT检查会给患者带来高剂量辐射，因此需要可靠的剂量测定。在这项工作中，通过铅笔电离室、热释光（TL）探测器和放射变色胶片测量空气或体模中的空气比释动能指数，从而对CT束进行剂量测定。校准结果表明，在100 - 120kV范围内，所有三种剂量测定系统的能量依赖性较低，与其他系统相比，TL剂量计的不确定性非常高，并且放射变色胶片在空气比释动能方面具有高非线性响应。在120kV CT协议中使用这三种系统进行的测量显示，加权空气比释动能指数值之间具有可接受的一致性，但TL剂量计的值具有最高的不确定性。