Radiation Dosimetry of Thyroid, Eye Lens and Salivary Glands in Adult and Paediatric Dental CBCT Scans: A Monte Carlo and Experimental Phantom Study

Zainab A.H. Al-Tamemi; Huda Ashur Shati Qutbi; Hussein Haleem Jasim

doi:10.51699/cajmns.v7i2.3153

Authors

Zainab A.H. Al-Tamemi College of Dentistry, University of Wasit, Wasit, Iraq
Huda Ashur Shati Qutbi College of Medicine, University of Wasit, Wasit, Iraq
Hussein Haleem Jasim College of Dentistry, University of Wasit, Wasit, Iraq

DOI:

https://doi.org/10.51699/cajmns.v7i2.3153

Keywords:

CBCT, Dosimetry, Monte Carlo, Pediatric, TLD

Abstract

Cone-beam computed tomography (CBCT) has been invaluable in modern dental and maxillofacial imaging, but much remains to be desired in terms of patient radiation safety especially to sensitive organs in the head and neck area and in children. This is a thorough research utilizing an integrated Monte Carlo computational and experimental phantom-based dosimetric technique to measure the primary, secondary and tertiary organ-specific doses to the thyroid gland, lens of the eye, and salivary glands in adult and pediatric dental CBCT scans. A phantom-based dosimetric study was a cross-sectional study with 20 anthropomorphic phantoms (12 adults, 8 children, age 5, 10, 15 years old) and three clinically representative CBCT protocols. Simulations Monte Carlo simulations Monte Carlo simulations (MCNPX version 2.7.0) were carried out and their results compared with experimental results of thermoluminescent dosimetry (TLD) using calibrated anthropomorphic phantoms. Two thousand and zero individual TLD measurements along with the Monte Carlo simulations were carried out. A thorough uncertainty analysis and statistical validation were done, and an a priori acceptance criterion was excellent agreement of <±10% different. Superior concordance was observed between Monte Carlo and experimental methods; 95.8% of measurements were rated as being exceptional (±10% difference) and zero measurements were higher than the ±15% failure limit. The analysis of linear regression produced the R 2 values of 0.994-0.998 and the slope estimate of 0.979-1.012. The comparison between groups with paired t-tests did not show any statistically significant differences (all p-values above 0.15). Intensive dose escalation with age was also reported: five year old children had 1.69 higher thyroid dose and 1.61 higher eye lens dose than adults. The mean thyroid doses varied between 1.19-3.41 mGy (adults) and 1.29-6.03 mGy (5-year-olds). The effective doses measured between 0.018 and 0.108 mSv among protocols and age. The expanded measurement uncertainty was 5.8 percent with a standard deviation of 0.8. The presented comprehensive study has definitively validated Monte Carlo computational dosimetry to maxillofacial CBCT imaging and gave empirically validated age-stratified organ dose data that can be used to optimize evidence-based protocols, develop diagnostic reference level, and make informed clinical decisions in dental practice.

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