Determination of size-specific exposure settings in dental cone-beam CT
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To estimate the possible reduction of tube output as a function of head size in dental cone-beam computed tomography (CBCT).
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.
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.
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.
• 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
KeywordsCone-beam computed tomography Dentistry Paediatrics Radiation protection Noise
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.
- 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
- 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.Nemtoi A, Czink C, Haba D, Gahleitner A (2013) Cone beam CT: a current overview of devices. Dentomaxillofac Radiol. 42:20120443Google Scholar
- 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.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
- 11.Pauwels R, Jacobs R, Singer SR, Mupparapu M (2015) CBCT-based bone quality assessment: are Hounsfield units applicable? Dentomaxillofac Radiol. 44:20140238Google Scholar
- 13.Kapila SD, Nervina JM (2015) CBCT in orthodontics: assessment of treatment outcomes and indications for its use. Dentomaxillofac Radiol. 44:20140282Google Scholar
- 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
- 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
- 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
- 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