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Evaluation of Thyroid Absorption Dose During Chest Imaging by Monte Carlo Simulation (DOSXYZnrc)
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F Ghahremani1    , Z Salehi 2 |
1- Student Research Committee, Yasuj University of Medical Sciences, Yasuj, Iran
2- Department of Radiology, Yasuj University of Medical Sciences, Yasuj, Iran , phyzaker@gmail.com |
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Abstract: (1485 Views) |
Background & aim: Chest radiography is one of the most common X-ray imaging procedures performed worldwide. During this process, in addition to the thorax, other tissues, including the thyroid, are exposed to radiation. Due to the fact that one of the most important risk factors for thyroid cancer is ionizing radiation, measuring the absorption of these rays in the thyroid is of particular importance. The aim of the present study was to determine and evaluate the absorbed dose of thyroid during chest imaging by Monte Carlo simulation method.
Methods: the present descriptive study was performed in 2020 at Yasuj University of Medical Sciences. In this study, ROEM radiographic device made by Siemens company was first simulated using Monte Carlo coding method using BEAMnrc. Then, using CT scan images of the chest obtained from the patients and by CTCREATE phantom-chest method, the design and energies of 100, 70 and 80 kV in Monte Carlo code were used. 300 million particles were used in the BEAMnrc simulation and 100 million particles in the DOSXYXnrc simulation. Thyroid uptake was calculated using BEAMdp from the outputs obtained in the BEAMnrc simulation. PDD diagrams for different energies were also drawn and analyzed using Excel software.
Results: The results showed that D / Dmax in different coordinates include different values in the range of 0.54 to 6.91. The calculation error was calculated from 0.32 to 18.73%. As well as, the values obtained in PDD diagrams showed relatively higher accuracy than similar studies that used different methods in dosimetry.
Conclusion: This study showed that dose absorption in the thyroid is present in all energy ranges that are typically performed on chest radiography. The results showed that in some places the amount of absorbed dose was more than 6 times the surface dose.
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| Keywords: Monte Carlo, CXR, DOSExyznrc, BEAMdp |
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Full-Text [PDF 1203 kb]
(370 Downloads)
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Type of Study: Research |
Subject:
Special
Received: 2020/08/17 | Accepted: 2020/10/5 | Published: 2021/03/2
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