Spatial resolution measurements by Radia diagnostic software with SEDENTEXCT image quality phantom in cone beam CT for dental use

Abstract

Objectives: We aimed to employ the Radia diagnostic software with the safety and efficacy of a new emerging dental X-ray modality (SEDENTEXCT) image quality (IQ) phantom in CT, and to evaluate its validity.

Methods: The SEDENTEXCT IQ phantom and Radia diagnostic software were employed. The phantom was scanned using one medical full-body CT and two dentomaxillofacial cone beam CTs. The obtained images were imported to the Radia software, and the spatial resolution outputs were evaluated. The oversampling method was employed using our original wire phantom as a reference. The resultant modulation transfer function (MTF) curves were compared. The null hypothesis was that MTF curves generated using both methods would be in agreement. One-way analysis of variance tests were applied to the f50 and f10 values from the MTF curves. The f10 values were subjectively confirmed by observing the line pair modules.

Results: The Radia software reported the MTF curves on the xy-plane of the CT scans, but could not return f50 and f10 values on the z-axis. The null hypothesis concerning the reported MTF curves on the xy-plane was rejected. There were significant differences between the results of the Radia software and our reference method, except for f10 values in CS9300. These findings were consistent with our line pair observations.

Conclusions: We evaluated the validity of the Radia software with the SEDENTEXCT IQ phantom. The data provided were semi-automatic, albeit with problems and statistically different from our reference. We hope the manufacturer will overcome these limitations.

Figure 1.

SEDENTEXCT image quality phantom (a). The appearance of the phantom and the lid. (b). The left image shows a sectional view at the section of 4 of the phantom using the Radia software, and the right drawing explains the insert modules. The modules of ①, ②, ③ and ④ were an edge for a line spread function, a 0.25 µm wire for a point spread function, line pairs on the xy-plane and line pairs on the z-axis, respectively. (c). The left photograph shows the line pairs for the xy-plane (the left side of the photo) and z-axis (the right side of the photo). The right radiological image is a projection image of the line pair module on the xy-plane. SEDENTEXCT, safety and efficacy of a new emerging dental X-ray modality.

Figure 2.

The MTF curves, and the line pair images in multislice CT, Sensation 64. MTF on the xy-plane (a) and z-axis (b). The curves are representative of the three repeated measurements (c). The images show the line pairs modules, which were reconstructed with H60s kernel, with a slice thickness of 0.6 mm. MTF, modulation transfer function.

Figure 3.

The modulation transfer function (MTF) curves, and the line pair images in the two types of cone beam CT, CS9300 (a–c) and 3D eXam (d–f). MTF on the xy-plane (a and d) and z-axis (b and e). These curves are representative of the three repeated measurements. The Radia software returned errors against the MTF in the z-axis and failed to demonstrate the data (c). The images show the line pairs on the xy-plane and z-axis, the slice thicknesses are the same as the voxel sizes, (i.e. 0.25 mm in CS9300 and 0.3 mm in 3D eXam).