The Effects of Single and Bimetallic Silicon Composite Shields in Medical Imaging Methods: A Monte Carlo Study

Abbas Ali  Nazeri; Reza  Malekzadeh; Parinaz  MehnatiMehnati; Soheila  Refahi

doi:10.18502/fbt.v12i1.17741

Abbas Ali Nazeri Department of Medical Physics, School of Medicine Tabriz University of Medical Sciences, Tabriz, Iran
Reza Malekzadeh Department of Medical Physics, School of Medicine Tabriz University of Medical Sciences, Tabriz, Iran
Parinaz MehnatiMehnati Medical Radiation Sciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Soheila Refahi Department of Medical Physics, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran

DOI: https://doi.org/10.18502/fbt.v12i1.17741

Keywords: Bismuth; Tin; Tungsten; Nanocomposites; Computed Tomography Shields; Patient Radiation

Abstract

Purpose: Nowadays, the use of polymer composites with several metals to design and build new radiation composite shields with practical features in radiology is expanding.

Materials and Methods: Three metal oxides, including Bismuth oxide (Bi₂O₃), Tungsten oxide (WO₃), and Tin oxide (SnO₂) were used as mono-metal and bimetallic compound silicon matrixes for clarification of their practical use. Monte Carlo simulation methods were used to enter the specifications of each metal in combination with silicon. The mass attenuation coefficients of the mono- and bimetallic composites were calculated in the energy ranges of 40 to 150 KeV by classification to low/ medium/high groups.

Results: The results showed the beam reduction ability for both the mono- and the bimetallic composites. The mass attenuation coefficients of Bi₂O₃, WO₃, and SnO₂ at 80 KeV were 0.38, 0.33, and 0.57 cm²/gr, respectively. Moreover, the Bismuth-Tin bimetallic combination at low energies and the Bismuth-Tungsten at high energies had better attenuation than the other samples. To select bimetallic compounds with a high attenuation coefficient, it is better to match the energy used in the imaging method specifically. For example, in the 70-90 KeV energy range, the Sn-W combination had the highest beam attenuation coefficient.

Conclusion: The advantage of mono- and bimetallic shields in terms of energy attenuation amount depends on beam energy and shielding metal “K-absorption” edge. In comparing the attenuation of recorded beams in low, medium, and high ranges of energy, mono-metallic Bismuth shows higher attenuation coefficients than mono-metallic Tungsten and bi-metallic Bismuth–Tungsten. Dose reduction of the bi-metallic state of Bismuth - Tin was greater than that of mono-metallic Bismuth and Tin in low energies. Also, the attenuation of the Bi-Sn composite shield in low energy was the highest amount among all silicon composite shields.