Cone-beam computed tomography for routine orthodontic treatment planning: a radiation dose evaluation.
BACKGROUND
Because of the advantages and possibilities of cone-beam computed tomography (CBCT), orthodontists use this method routinely for patient assessment. The aim of this study was to compare the radiation doses for conventional panoramic and cephalometric imaging with the doses for 2 different CBCT units and a multi-slice CT unit in orthodontic practice.


METHODS
The absorbed organ doses were measured by using an anthropomorphic phantom loaded with thermoluminescent dosimeters at 16 sites related to sensitive organs. The 4 devices (Sirona DS Plus [Sirona Dental Systems, Bernsheim, Germany], i-CAT [Imaging Sciences International, Hatfield, Pa], NewTom DVT 9000 [QR, Verona, Italy], and Somatom Sensation [Siemens Medical Solutions, Erlangen, Germany]) were used with standard protocols and, when possible, in the auto-exposure mode. Equivalent and effective doses were calculated. The calculation of the effective doses was based on the International Commission on Radiological Protection's 2005 recommendations.


RESULTS
The lowest organ dose (13.1 microSv) was received by the thyroid gland during conventional panoramic and lateral cephalometric imaging. The highest mean organ dose (15,837.2 microSv) was received by the neck skin from the multi-slice CT. The effective dose was also lower for the panoramic and lateral cephalometric device (10.4 microSv), and highest for the multi-slice CT (429.7 microSv).


CONCLUSIONS
From a radiation-protection point of view, conventional images still deliver the lowest doses to patients. When 3-dimensional imaging is required in orthodontic practice, a CBCT should be preferred over a CT image. Further studies are necessary to justify the routine use of CBCT in orthodontic treatment planning.
Silva
Maria Alves Garcia
MA
Department of Stomatologic Sciences, School of Dentistry, Federal University of Goiás, Goiás, Brazil. magss@odonto.ufg.br
Wolf
Ulrich
U
Heinicke
Frank
F
Bumann
Axel
A
Visser
Heiko
H
Hirsch
Edgar
E
D002508:Cephalometry; D054893:Cone-Beam Computed Tomography / Q000295:instrumentation; D008310:Malocclusion / Q000000981:diagnostic imaging*; D010347:Patient Care Planning; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011861:Radiography, Dental / Q000379:methods*; D011862:Radiography, Panoramic; D014057:Tomography, X-Ray Computed