Development of a low-dose protocol for cone beam CT examinations of the anterior maxilla in children.
OBJECTIVE
The aim of this study was to develop a low-dose protocol suitable for cone beam CT (CBCT) examination of an impacted maxillary canine in children by using a combination of dosimetry with subjective and objective image quality assessment.


METHODS
Radiation dose and image quality measurements were made using a dental CBCT machine. An image quality phantom was used to investigate the relationship between objective image quality and dose-area product (DAP) for a broad range of exposure settings. Subjective image quality assessment was achieved using a paediatric skull phantom submerged in a water bath for the same range of exposure settings. Eight clinicians assessed each CBCT data set for nine aspects of image quality using a five-point rating scale of agreement.


RESULTS
Acceptable image quality, defined using subjective judgements by the clinicians of the skull phantom images, was achievable with DAP values of 127 mGy cm(2) or greater and a polytetrafluoroethylene (PTFE) contrast-to-noise ratio (CNR) of 4.8 or greater. A cautious choice was made to recommend a low-dose protocol of 80 kV and 3 mA for implementation into clinical practice, corresponding to a DAP value of 146 mGy cm(2) and a PTFE CNR of 5.0.


CONCLUSIONS
A low-dose protocol for this particular CBCT machine was established which represents as much as a 50% reduction compared with manufacturer's recommendations.


CONCLUSIONS
To the authors' best knowledge, this is the first study that addresses dose optimization in paediatric clinical protocols in dental CBCT. Furthermore, this study explores the relationship between radiation dose, objective and subjective image quality.
1 School of Dentistry, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK.
Jose A
JA
Hidalgo Rivas
1 School of Dentistry, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK.
Keith
K
Horner
1 School of Dentistry, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK.
Badri
B
Thiruvenkatachari
1 School of Dentistry, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK.
Jonathan
J
Davies
2 Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK (Hidalgo Rivas is now with Depto. de Estomologia, Universidad deTalca, Talca, Chile).
Chrysoula
C
Theodorakou
D002648:Child; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008437:Maxilla / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D011829:Radiation Dosage