Image quality and dose assessment in inner ear computed tomography imaging with a flat panel-based system.

PURPOSE: The temporal bone includes several important structures of the human body, some of which are smaller than 1 mm. The aim of this study is to demonstrate the feasibility of a computed tomography system capable of providing 3-dimensional images of the inner ear with low doses and a spatial resolution adequate for providing the surgeon with good guidance. METHODS: A laboratory prototype, based on a CMOS Hamamatsu model C10900D detector, was set up, and several tomographic tests were carried out on 2 dedicated phantoms. RESULTS: The proposed system is able to achieve a 150-µm spatial resolution (5% of modulation transfer function) with a voxel size of 88 µm, with an acceptable contrast and an estimated effective dose ranging from 1/20 up to 1/100 of the mean effective dose reported in literature for head computed tomography. CONCLUSION: The new tomographic system has shown excellent characteristics and proves suitable for the imaging of the inner ear. In particular, this prototype requires very low radiation doses.