Document Type : Original Article

Authors

1 Department of Medical Physics, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran

2 Department of Social Medicine, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran

3 Department of Radiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran

10.30476/mejc.2021.85833.1306

Abstract

Background: Despite significant diagnosis benefits, the usage of ionizing radiation is not risk-free. The aim of this study was to determine the risk of thyroid cancer for children who exposed from brain computed tomography (CT) scan.
Method: In this a cross-sectional study, 90 patients under 20 years of age who underwent brain CT-scan were selected. Parameters such as age, sex, imaging technique, imaging characteristics, and thyroid absorbed dose were considered. We used SPSS software, version 21, at 95% confidence interval to analyze the absorbed dose and risk for each individual.
Results: The mean and standard deviation of absorbed the dose for girls and boys for the spiral technique were 3.954±0.393 and 4.72±0.000 mGy and in sequential technique, they were 2.282±0.461 and 1.985±0.431 mGy, respectively. The mean and standard deviation of the absorbed dose in <5 years age group was 5.65±2.00, 3.03±1.34 in 6 to 10 years, 2.63±0.98 in11 to 15 years, and in 16 to 20 years was 2.57±1.04 mGy (P<0.001). There was a significant negative correlation between the absorbed dose and field dimensions (r = -0.604, P<0.001) and slice thickness (r = -0.777, P<0.001). The mean and standard deviation of Lifetime risk for thyroid cancer induction (×105) in <5 years age group in spiral technique was 158.79±322.50 for female subjects and 16.5±42.90 for male patients, which was significantly more than those of other groups and techniques (P<0.001).
Conclusion: The rate of thyroid absorbed dose during brain CT-scan was found to be noticeable, especially in spiral CT imaging, for female patients < 5 years. Based on our results, it was associated with an increased risk of thyroid cancer in this age group.

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This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination, and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi:10.30476/mejc.2021.85833.1306