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CC BY 4.0 · World J Nucl Med 2023; 22(03): 217-225
DOI: 10.1055/s-0043-1771287
Original Article

Impact of Wolfmet Tungsten Alloys as Parallel-Hole Collimator Material on Single-Photon Emission Computed Tomography Image Quality and Functional Parameters: A Simulating Medical Imaging Nuclear Detectors Monte Carlo Study

Maryam Darami
1   Medical Radiation Sciences Research Team, Tabriz University of Medical Sciences, Tabriz, Iran
,
Babak Mahmoudian
2   Department of Nuclear Medicine, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
,
Michael Ljungberg
3   Medical Radiation Physics, Lund University, Lund, Sweden
,
Jalil Pirayesh Islamian 
4   Department of Medical Physics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
› Author Affiliations Funding This work was financially supported by a grant from the Medical Radiation Sciences Research Team, Tabriz University of Medical Sciences, Tabriz, Iran (Grant no # 65077).
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Abstract

Objectives Collimators have a significant role in image quality and detectability in single-photon emission computed tomography (SPECT) imaging. Using an appropriate alloy that effectively absorbs scattered photons, without induced secondary x-rays, and with proper rigidity and weight may provide an effective approach to the image improvement that conventionally collimators made of lead (Pb).

Materials and Methods A Siemens E.CAM SPECT imaging system equipped with low-energy high-resolution (LEHR) collimator was simulated by the Simulating Medical Imaging Nuclear Detectors Monte Carlo program. Experimental and simulated data were compared based on a 2-mm 99mTc point source in an acrylic cylindrical Deluxe phantom (Data Spectrum, Inc). Seven types of tungsten (W) alloys (Wolfmet), with W content from 90 to 97% by weight, were then used as collimator materials of the simulated system. Camera parameters, such as energy- and spatial resolution, image contrast, and collimator-related parameters, such as fraction of septal penetration, scatter-to-primary ratios, and percentage of induced secondary x-rays, due to interactions in the collimator, were evaluated.

Results Acceptable conformity was found for the simulated and experiment systems in terms of energy spectra, 10.113 and 10.140%, full width at half-maximum (FWHM) of the point spread function (PSF) curves, 8.78 and 9.06 mm, sensitivity, 78.46 and 78.34 cps/MBq, and contrast in images of 19.1 mm cold spheres in the Deluxe phantom, 79.17 and 78.97%, respectively. Results on the parameters of the simulated system with LEHR collimator made from the alloys showed that the alloy consisting of 90% W, 6% nickel, and 4% copper provided an FWHM of 8.76 mm, resulting in a 0.2% improvement in spatial resolution. Furthermore, all the Wolfmet collimators showed a 48% reduction in the amount of X-rays production compared to the Pb.

Conclusion A Wolfmet LEHR collimator, made by a combination of W (90%), Ni (6%), and Cu (6%) provides a better image quality and detectability compared to the Pb.

Keywords

Wolfmet - collimator - image quality - SPECT - SIMIND - tungsten

Authors' Contribution

M.D. was responsible for writing—original draft, visualization, methodology, investigation, data curation, and conceptualization. B.M was responsible for writing—review and editing, supervision, formal analysis, and conceptualization. M.L. was responsible for providing materials for SIMIND simulation, review, and editing. J.P.I. was responsible for writing—review and editing, supervision, funding acquisition, and conceptualization.




Publication History

Article published online:
06 September 2023

© 2023. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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  • References

  • 1 Lee SJ, Park HJ. Single photon emission computed tomography (SPECT) or positron emission tomography (PET) imaging for radiotherapy planning in patients with lung cancer: a meta-analysis. Sci Rep 2020; 10 (01) 14864
    CrossrefPubMedGoogle Scholar
  • 2 Sadremomtaz A, Telikani Z. Validation and optimization studies of small animal SPECT using GATE Monte Carlo simulation. Nucl Instrum Methods Phys Res A 2019; 915: 94-101
    CrossrefGoogle Scholar
  • 3 Taherparvar P, Sadremomtaz A. Development of GATE Monte Carlo simulation for a CsI pixelated gamma camera dedicated to high resolution animal SPECT. Australas Phys Eng Sci Med 2018; 41 (01) 31-39
    CrossrefPubMedGoogle Scholar
  • 4 Wang Y. . Development and applications of high-sensitivity and high-resolution fully three-dimensional SPECT imaging techniques using two different collimator designs. The University of North Carolina at Chapel Hill; 2004.
  • 5 Baghani HR. Image quality parameters in brain imaging with fan-beam collimator: a Monte Carlo study on radiation scattering effects. Radiological Phys Technol 2019; 12 (02) 194-200
    CrossrefPubMedGoogle Scholar
  • 6 McQuaid SJ, Southekal S, Kijewski MF, Moore SC. Joint optimization of collimator and reconstruction parameters in SPECT imaging for lesion quantification. Phys Med Biol 2011; 56 (21) 6983-7000
    CrossrefPubMedGoogle Scholar
  • 7 Islamian JP, Toossi MT, Momennezhad M, Zakavi SR, Sadeghi R, Ljungberg M. Monte Carlo study of the effect of collimator thickness on T-99m source response in single photon emission computed tomography. World J Nucl Med 2012; 11 (02) 70-74
    Article in Thieme ConnectPubMedGoogle Scholar
  • 8 Khorshidi A, Ashoor M, Hosseini SH, Rajaee A. Estimation of fan beam and parallel beam parameters in a wire mesh design. J Nucl Med Technol 2012; 40 (01) 37-43
    CrossrefPubMedGoogle Scholar
  • 9 Khorshidi A, Ashoor M, Hosseini SH, Rajaee A. Evaluation of collimators' response: round and hexagonal holes in parallel and fan beam. Prog Biophys Mol Biol 2012; 109 (03) 59-66
    CrossrefPubMedGoogle Scholar
  • 10 Rajaee A, Shahriari M, Kamali AA, Hosseini S. Simulation study of the influence of collimator material on image quality improvement for high energy photons in nuclear medicine using MCNP code. J Theor Appl Phys 2011; 4 (04) 13-18
    Google Scholar
  • 11 Lee Y-J, Kim D-H, Kim H-J. The effect of high-resolution parallel-hole collimator materials with a pixelated semiconductor SPECT system at equivalent sensitivities: Monte Carlo simulation studies. J Korean Phys Soc 2014; 64: 1055-1062
    CrossrefGoogle Scholar
  • 12 Gopal S, Sanjeevaiah B. A method to determine the γ-ray attenuation coefficients. Nucl Instrum Methods 1973; 107 (02) 221-225
    CrossrefGoogle Scholar
  • 13 Rezaei-Ochbelagh D, Azimkhani S. Investigation of gamma-ray shielding properties of concrete containing different percentages of lead. Appl Radiat Isot 2012; 70 (10) 2282-2286
    CrossrefPubMedGoogle Scholar
  • 14 Kobayashi S, Hosoda N, Takashima R. Tungsten alloys as radiation protection materials. Nucl Instrum Methods Phys Res A 1997; 390 (03) 426-430
    CrossrefGoogle Scholar
  • 15 Directive E. Restriction of the use of certain hazardous substances in electrical and electronic equipment (RoHS). Off J Eur Communities 2013; 46: 19-23
    Google Scholar
  • 16 Van Audenhaege K, Van Holen R, Vandenberghe S, Vanhove C, Metzler SD, Moore SC. Review of SPECT collimator selection, optimization, and fabrication for clinical and preclinical imaging. Med Phys 2015; 42 (08) 4796-4813
    CrossrefPubMedGoogle Scholar
  • 17 Lee Y-J, Ryu H-J, Lee S-W, Park S-J, Kim H-J. Comparison of ultra-high-resolution parallel-hole collimator materials based on the CdTe pixelated semiconductor SPECT system. Nucl Instrum Methods Phys Res A 2013; 713: 33-39
    CrossrefGoogle Scholar
  • 18 Weng F, Bagchi S, Huang Q, Seo Y. . Design Studies of a CZT-based detector combined with a pixel-geometry-matching collimator for SPECT imaging. Paper presented at: 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC); 2013.
  • 19 Peterson M, Strand SE, Ljungberg M. Using Rose's metal alloy as a pinhole collimator material in preclinical small-animal imaging: a Monte Carlo evaluation. Med Phys 2015; 42 (04) 1698-1709
    CrossrefPubMedGoogle Scholar
  • 20 Handtrack D, Tabernig B, Kestler H, Pohl P, Glatz W, Sigl L. . Tungsten heavy alloys for collimators and shieldings in the X-ray diagnostics. Paper presented at: Proceedings of 18th PLANSEE seminar on refractory metals and hard materials; 2013.
  • 21 Dong M, Tishkevich D, Hanfi M. et al. WCu composites fabrication and experimental study of the shielding efficiency against ionizing radiation. Radiat Phys Chem 2022; 200: 110175
    CrossrefGoogle Scholar
  • 22 Kaur T, Sharma J, Singh T. Review on scope of metallic alloys in gamma rays shield designing. Prog Nucl Energy 2019; 113: 95-113
    CrossrefGoogle Scholar
  • 23 Murty VR, Winkoun DP, Devan KR. Effective atomic numbers for W/Cu alloy using transmission experiments. Appl Radiat Isot 2000; 53 (4–5): 945-948
    CrossrefPubMedGoogle Scholar
  • 24 Murty VR. Effective atomic numbers for W/Cu alloy for total photon attenuation. Radiat Phys Chemi 2004; 71 (3–4): 667-669
    CrossrefGoogle Scholar
  • 25 Auer B, De Beenhouwer J, Kalluri K, Goding JC, Furenlid LR, King MA. . Preliminary investigation of design parameters of an innovative multi-pinhole system dedicated to brain SPECT imaging. Paper presented at: 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference Proceedings (NSS/MIC); 2018.
  • 26 Nguyen MP, Goorden MC, Kamphuis C, Beekman FJ. Evaluation of pinhole collimator materials for micron-resolution ex vivo SPECT. Phys Med Biol 2019; 64 (10) 105017
    CrossrefPubMedGoogle Scholar
  • 27 Wolfmet. Wolfmet tungesten alloys radiation shielding data sheet. Accessed April 3, 2022 at: https://www.wolfmet.com/wp-content/uploads/2017/01/Wolfmet_Radiation_Shielding2.pdf 2017 .
    PubMed
  • 28 Ljungberg M, Strand S-E. A Monte Carlo program for the simulation of scintillation camera characteristics. Comput Methods Programs Biomed 1989; 29 (04) 257-272
    CrossrefPubMedGoogle Scholar
  • 29 Bahreyni Toossi MT, Islamian JP, Momennezhad M, Ljungberg M, Naseri SH. SIMIND Monte Carlo simulation of a single photon emission CT. J Med Phys 2010; 35 (01) 42-47
    CrossrefPubMedGoogle Scholar
  • 30 Islamian JP, Toossi MT, Momennezhad M, Zakavi SR, Sadeghi R. Monte Carlo study of the effect of backscatter material thickness on 99mTc source response in single photon emission computed tomography. Iran J Med Phys 2013; 10 (1–2): 69-77
    Google Scholar
  • 31 Pirayesh IJ, Bahreyni TMT, Momennezhad M, Naseri S, Ljungberg M. Simulation of a quality control Jaszczak phantom with SIMIND Monte Carlo and adding the phantom as an accessory to the program. Iran J Med Phys 2012; 9 (02) 135-140
    Google Scholar
  • 32 Blust J. Gamma camera acceptance testing: the first quality control. J Nucl Med Technol 1994; 22 (02) 58-61
    Google Scholar
  • 33 Busemann Sokole E, Płachcínska A, Britten A, Lyra Georgosopoulou M, Tindale W, Klett R. EANM Physics Committee ; EANM Working Group on Nuclear Medicine Instrumentation Quality Control. Routine quality control recommendations for nuclear medicine instrumentation. Eur J Nucl Med Mol Imaging 2010; 37 (03) 662-671
    CrossrefPubMedGoogle Scholar
  • 34 Azarm A, Islamian JP, Mahmoudian B, Gharepapagh E. The effect of parallel-hole collimator material on image and functional parameters in SPECT imaging: A SIMIND Monte Carlo study. World J Nucl Med 2015; 14 (03) 160-164
    Article in Thieme ConnectPubMedGoogle Scholar
  • 35 Wolfmet. Wolfmet tungsten alloys technical information. Accessed April 3, 2022 at: https://www.wolfmet.com/wp-content/uploads/2017/01/Wolfmet_Tungsten_Alloys_Technical_Information1.pdf .. 2019 .
    PubMed