Determination of lower dose protocols with suitable image quality for an off-axis geometry computed tomography unit

Abstract

Although dental computed tomography exams offer a relatively low radiation dose to the patient, substantial evidences regarding stochastic effects of ionizing radiation indicate that even small doses may induce effects such as carcinogenesis. Therefore, exposure parameters should be adjusted keeping radiation dose as low as diagnostically acceptable. The aim of this study is to determine the optimal balance between energetic parameters of tube voltage and tube current on the partial detectors systems Picasso Trio (Vatech, Vatech, Hwaseong, Korea), OP300 Maxio (Instrumentarium Dental, Tuusula, Finland) and PaX-i3D Green Premium (Vatech, Vatech, Hwaseong, Korea), for adult and pediatric patients, as well as to study the influence of using partial detectors in image quality and radiation dose. To achieve the optimal balance between energetic parameters, anthropomorphic phantoms will be scanned under several combinations of tube voltage, tube current and fields of view. Clinical assessment regarding general quality and anatomical structures related to diagnostic tasks will be performed, as well as quantitative assessment of image noise and artifacts. A Polymethyl Methacrylate (PMMA) phantom with coupled ionization chambers will be exposed to radiation under different energetic parameters on Picasso Trio, OP300 Maxio and PaX-i3D Green Premium systems for the dosimetric study. Moreover, to study the influence of using partial detector a PMMA phantom with inserts containing aluminium and air will be scanned on Picasso Trio, OP300 Maxio, PaX-i3D Green Premium and Accuitomo 3D 170 (J. Morita MFG. Corp., Kyoto, Japan) systems to measure noise in basis images and compare systems. (AU)