Development and validation of two phantoms for quality control in cone-beam CT

This study aimed at the development and validation of the models of phantom: CQ-02-IFBA and CQ-01-IFBA, the first filled with water and the second fully with a solid structure in polymethylmethacrylate (PMMA). Both models allow its use in various models of cone beam computed tomography (CBCT), independent of the size of the field of view. The two phantoms are used to evaluate seven parameters of quality control: intensity or average value of pixels of five different plastics, signal to noise ratio, resolution, low contrast, spatial resolution, the accuracy of distances on the z axis, the geometric distortion and image uniformity. Spatial resolution is a critical parameter that differs significantly in the various imaging modalities in dental radiology, and in these two phantoms, it can be evaluated by two different methods: MTF obtained by Fourier transformation of the function LSF (line spread function) and/or by analysis visual image to a pattern of bars up to 16 lp/cm. Validation was performed in three models CBCT: CareStream CS 9000 3D, i-CAT Classical and Sirona Orthophos XG 3D. The two phantom models were viable and also complied with the specifications and data available in the literature. It is concluded that the two phantom models are viable for use in CBCT with different characteristics.