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European Radiology

, Volume 27, Issue 1, pp 279–285 | Cite as

Determination of size-specific exposure settings in dental cone-beam CT

  • Ruben PauwelsEmail author
  • Reinhilde Jacobs
  • Ria Bogaerts
  • Hilde Bosmans
  • Soontra Panmekiate
Physics

Abstract

Objectives

To estimate the possible reduction of tube output as a function of head size in dental cone-beam computed tomography (CBCT).

Methods

A 16 cm PMMA phantom, containing a central and six peripheral columns filled with PMMA, was used to represent an average adult male head. The phantom was scanned using CBCT, with 0-6 peripheral columns having been removed in order to simulate varying head sizes. For five kV settings (70-90 kV), the mAs required to reach a predetermined image noise level was determined, and corresponding radiation doses were derived. Results were expressed as a function of head size, age, and gender, based on growth reference charts.

Results

The use of 90 kV consistently resulted in the largest relative dose reduction. A potential mAs reduction ranging from 7 % to 50 % was seen for the different simulated head sizes, showing an exponential relation between head size and mAs. An optimized exposure protocol based on head circumference or age/gender is proposed.

Conclusions

A considerable dose reduction, through reduction of the mAs rather than the kV, is possible for small-sized patients in CBCT, including children and females. Size-specific exposure protocols should be clinically implemented.

Key Points

Fixed exposure settings in CBCT results in overexposure for smaller patients

For children, considerable dose reduction is possible without compromising image quality

A reduction in mAs is more dose-efficient than a kV reduction

An optimized exposure protocol was proposed based on phantom measurements

This protocol should be validated in a clinical setting

Keywords

Cone-beam computed tomography Dentistry Paediatrics Radiation protection Noise 

Notes

Acknowledgments

The scientific guarantor of this publication is Dr. Ruben Pauwels. The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article. This study has received funding by Chulalongkorn University.

No complex statistical methods were necessary for this paper. Institutional Review Board approval was not required because this was a phantom study. Methodology: experimental, multicenter study.

Supplementary material

330_2016_4353_MOESM1_ESM.pdf (633 kb)
ESM 1 (PDF 633 kb)
330_2016_4353_Fig7_ESM.gif (8 kb)
Figure A1

Attenuation of a 50 keV X-ray beam passing through polymethyl methacrylate (PMMA), as a function of PMMA thickness. Data based on NIST tables [1]. (GIF 7 kb)

330_2016_4353_MOESM2_ESM.tif (930 kb)
High resolution image (TIF 930 kb)
330_2016_4353_Fig8_ESM.gif (9 kb)
Figure A2

Relative mAs required to achieve a constant detector signal as a function of PMMA thickness, relative to 160 mm. Data based on NIST tables [1]. (GIF 8 kb)

330_2016_4353_MOESM3_ESM.tif (979 kb)
High resolution image (TIF 978 kb)

References

  1. 1.
    Pauwels R (2015) Cone beam CT for dental and maxillofacial imaging: dose matters. Radiat Prot Dosimetry 165:156–161CrossRefPubMedGoogle Scholar
  2. 2.
    International Commission on Radiological Protection (2007) The 2007 Recommendations of the International Commission on Radiological Protection. ICRP publication 103. Ann ICRP 37:1–332Google Scholar
  3. 3.
    Hidalgo-Rivas JA, Theodorakou C, Carmichael F, Murray B, Payne M, Horner K (2014) Use of cone beam CT in children and young people in three United Kingdom dental hospitals. Int J Paediatr Dent 24:336–348CrossRefPubMedGoogle Scholar
  4. 4.
    Pauwels R, Cockmartin L, Ivanauskaité D, Urbonienė A, Gavala S, Donta C (2014) Estimating cancer risk from dental cone-beam CT exposures based on skin dosimetry. Phys Med Biol 59:3877–3891CrossRefPubMedGoogle Scholar
  5. 5.
    Hall EJ, Brenner DJ (2008) Cancer risks from diagnostic radiology. Br J Radiol 81:362–378CrossRefPubMedGoogle Scholar
  6. 6.
    European Commission (2012) Cone Beam CT for Dental and Maxillofacial Radiology: Evidence Based Guidelines, Radiation Protection Publication 172. European Commission, Brussels, Belgium. Available via https://ec.europa.eu/energy/sites/ener/files/documents/172.pdf. Accessed 24 Aug 2015
  7. 7.
    Nemtoi A, Czink C, Haba D, Gahleitner A (2013) Cone beam CT: a current overview of devices. Dentomaxillofac Radiol. 42:20120443Google Scholar
  8. 8.
    Pauwels R, Stamatakis H, Manousaridis G, Walker A, Michielsen K, Bosmans H et al (2011) Development and applicability of a quality control phantom for dental cone-beam CT. J Appl Clin Med Phys 12:245–260Google Scholar
  9. 9.
    Pauwels R, Silkosessak O, Jacobs R, Bogaerts R, Bosmans H, Panmekiate S (2014) A pragmatic approach to determine the optimal kVp in cone beam CT: balancing contrast-to-noise ratio and radiation dose. Dentomaxillofac Radiol. 43:20140059Google Scholar
  10. 10.
    Rollins JD, Collins JS, Holden KR (2010) United States head circumference growth reference charts: birth to 21 years. J Pediatr 156:907–913CrossRefPubMedGoogle Scholar
  11. 11.
    Pauwels R, Jacobs R, Singer SR, Mupparapu M (2015) CBCT-based bone quality assessment: are Hounsfield units applicable? Dentomaxillofac Radiol. 44:20140238Google Scholar
  12. 12.
    Zhuang Z, Landsittel D, Benson S, Roberge R, Shaffer R (2010) Facial anthropometric differences among gender, ethnicity, and age groups. Ann Occup Hyg 54:391–402CrossRefPubMedGoogle Scholar
  13. 13.
    Kapila SD, Nervina JM (2015) CBCT in orthodontics: assessment of treatment outcomes and indications for its use. Dentomaxillofac Radiol. 44:20140282Google Scholar
  14. 14.
    Matzen LH, Wenzel A (2015) Efficacy of CBCT for assessment of impacted mandibular third molars: a review - based on a hierarchical model of evidence. Dentomaxillofac Radiol. 44:20140189Google Scholar
  15. 15.
    Alqerban A, Jacobs R, van Keirsbilck PJ, Aly M, Swinnen S, Fieuws S et al (2014) The effect of using CBCT in the diagnosis of canine impaction and its impact on the orthodontic treatment outcome. J Orthod Sci 3:34–40CrossRefPubMedPubMedCentralGoogle Scholar
  16. 16.
    Shahbazian M, Jacobs R, Wyatt J, Denys D, Lambrichts I, Vinckier F et al (2013) Validation of the cone beam computed tomography-based stereolithographic surgical guide aiding autotransplantation of teeth: clinical case-control study. Oral Surg Oral Med Oral Pathol Oral Radiol 115:667–675CrossRefPubMedGoogle Scholar
  17. 17.
    Starbuck JM, Ghoneima A, Kula K (2014) Facial soft-tissue asymmetry in three-dimensional cone-beam computed tomography images of children with surgically corrected unilateral clefts. J Craniofac Surg 25:476–480CrossRefPubMedGoogle Scholar
  18. 18.
    Iwasaki T, Hayasaki H, Takemoto Y, Kanomi R, Yamasaki Y (2009) Oropharyngeal airway in children with Class III malocclusion evaluated by cone-beam computed tomography. Am J Orthod Dentofacial Orthop 136:318.e1-9Google Scholar
  19. 19.
    Huntjens E, Kiss G, Wouters C, Carels C (2008) Condylar asymmetry in children with juvenile idiopathic arthritis assessed by cone-beam computed tomography. Eur J Orthod 30:545–551CrossRefPubMedGoogle Scholar
  20. 20.
    Bansal V, Singh S, Garg N, Dubey P (2014) Transport distraction osteogenesis as a method of reconstruction of the temporomandibular joint following gap arthroplasty for post-traumatic ankylosis in children: a clinical and radiological prospective assessment of outcome. Int J Oral Maxillofac Surg 43:227–236CrossRefPubMedGoogle Scholar
  21. 21.
    Sterkers F, Merklen F, Piron JP, Vieu A, Venail F, Uziel A et al (2015) Outcomes after cochlear reimplantation in children. Int J Pediatr Otorhinolaryngol 79:840–843CrossRefPubMedGoogle Scholar

Copyright information

© European Society of Radiology 2016

Authors and Affiliations

  • Ruben Pauwels
    • 1
    • 2
    Email author
  • Reinhilde Jacobs
    • 2
  • Ria Bogaerts
    • 3
  • Hilde Bosmans
    • 4
  • Soontra Panmekiate
    • 1
  1. 1.Department of Radiology, Faculty of DentistryChulalongkorn UniversityPatumwanThailand
  2. 2.OMFS-IMPATH Research Group, Department of Imaging and Pathology, Biomedical Sciences GroupUniversity of LeuvenLeuvenBelgium
  3. 3.Laboratory of Experimental Radiotherapy, Department of Oncology, Biomedical Sciences GroupUniversity of LeuvenLeuvenBelgium
  4. 4.Medical Physics & Quality Assessment, Department of Imaging and Pathology, Biomedical Sciences GroupUniversity of LeuvenLeuvenBelgium

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