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Evaluation of technical image quality and
radiation dose of a Thai cone-beam CT scanner
Authors :
- Ruben Pauwels, Ph.D.
- Saowapak Thongvigitmanee, Ph.D.
- Sorapong Aootaphao, M.S.
- Chalinee Thanasupsombat, M.S.
- Walita Narkbuakaew, D.Eng.
- Reinhilde Jacobs, Ph.D.
- Hilde Bosmans, Ph.D.
- Soontra Panmekiate, Ph.D.
- Pairash Thajchayapong, Ph.D.
Abstract :
Objectives The aim of this study is to evaluate the technical image quality and radiation dose of the
DentiiScan 2.0 cone-beam computed tomography (CBCT) scanner before widespread clinical use.
Materials and methods Image quality was measured for 4 scanning protocols of the DentiiScan
2.0, using 2 dedicated test objects: the SEDENTEXCT IQ phantom and the QRM-ConeBeam
phantom. The following image quality parameters were evaluated: contrast-detail, contrast-to-noise
ratio (CNR), spatial resolution, grey value uniformity, metal artefacts, and geometric accuracy. Radiation
dose was measured using a calibrated ionization chamber placed at the isocenter of rotation, allowing
for the calculation of the dose-area product (DAP).
Results For contrast-detail, scores were almost identical for all protocols, with all 5 rods being
distinguishable for aluminium, air, hydroxyapatite 200 mg/cm3, polytetrafluorethylene, and low-density
polyethylene. CNR values were commensurate with the contrast-detail results. Visual evaluation of
the line pair patterns revealed considerable differences between scanning protocols. Some consistency
between voxel size and sharpness could be seen. High grey value uniformity was found for Protocols
1-3; for Protocol 4 the uniformity was slightly worse. There was no difference in artefact severity
between scanning protocols. For geometric accuracy, average errors between 0.04 and 0.08 mm
were found, indicating high accuracy. The dose-area product was 897.1 mGy.cm2 for Protocol 1,
1058.4 mGy.cm2 for Protocol 2, 474.1 mGy.cm2 for Protocol 3, and 424.4 mGy.cm2 for Protocol 4.
Conclusion The DentiiScan 2.0 showed adequate performance in terms of technical image quality,
and a low radiation dose compared with other CBCT models. The protocol with the smallest FOV
provided the best balance between image quality and dose.
(CU Dent J. 2017;40:27-38)
Keywords :
cone-beam computed tomography, dentistry, image quality, radiation dose, Thailand
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