ABSTRACT

Objectives

To analyze the effect of changes in exposure settings, field of view (FOV), and shielding on radiation to an adult and child phantom from cone-beam computed tomography (CBCT) imaging compared to panoramic and lateral cephalometric radiographs.

Materials and Methods

The effective dose to an adult and child anthropomorphic phantom by the CS 9300 using various scan protocols was recorded. Absorbed radiation was measured with optically stimulated luminescence dosimeters and effective dose calculated using 2007 International Commission on Radiological Protection tissue weighting factors. Scan protocols included different FOVs, voxel sizes, and standard versus low-dose protocols. Radiation shielding was used when it did not interfere with FOV. Panoramic and lateral cephalometric radiographs were taken with the Orthophos SL.

Results

Even with shielding, smaller FOVs, and increased voxel sizes, the effective dose of standard CBCT scans was higher than panoramic and lateral cephalometric radiographs. A shielded limited FOV standard scan combined with a lateral cephalometric radiograph resulted in a lower dose (P < .001) than a full FOV standard scan. Low-dose shielded scans resulted in significant dose reductions to the adult (P < .05) and child (P < .001) phantoms compared to the respective panoramic and lateral cephalometric radiographs combined. Image quality analysis was not possible with radiation equivalent phantoms.

Conclusions

Unlike standard CBCTs, shielded low-dose CBCT protocols in the CS 9300 have lower effective doses than conventional radiographs for adult and child phantoms. If high resolution and cranial base visualization are necessary, combining a shielded LFOV standard exposure with a cephalometric radiograph is recommended.

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Author notes

a

Orthodontic Resident, Harvard School of Dental Medicine, Boston, Mass, USA.

b

Teaching Assistant, Department of Oral and Maxillofacial Radiology, Ain Shams University, Cairo, Egypt.

c

Assistant Clinical Professor, Department of Diagnostic Sciences, University of North Carolina School of Dentistry, Chapel Hill, N.C., USA.

d

Assistant Professor, Military Technical College, Cairo, Egypt.

e

Associate Professor, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Mass, USA.

f

Brodie Craniofacial Endowed Chair and Professor, Department of Orthodontics, University of Illinois College of Dentistry, Chicago, Ill, USA.

g

Assistant Professor, Department of Developmental Biology, Director of Advanced Graduate Education in Orthodontics, Harvard School of Dental Medicine, Boston, Mass, USA.