A basic study of high resolution CT

High resolution CT is useful in the evaluation of complex anatomy and disease processes of the temporal bones, skullbase and orbital bones. Spatial and contrast resolution is an important parameter for the evaluation of performance of computerized tomography (CT) scanners. A survey of seven production CT scanners in clinical use has been carried out with two types of phantoms : commercially available phantoms and a phantom developed by the author. The CT scanners evaluated in this study were TCT60A-50, SCT2000T-11, CT/T8800, CT/T9800, DELTA 2020G, DELTA 2020HR, and TCT-900S. Measurements were made of spatial resolution, magnification, slice thickness and dose relationship with use of these phantoms. The phantom developed by the author was designed to evaluate CT scanner performance relative to spatial resolution of smaller objects. This study also evaluated the relationship between dose and picture quality parameters. The performance of seven CT scanners, five of third, and two of fourth generation, was carefuly evaluated and the desirable techniques to obtain good images were disscussed in relation to X-ray dose, slice thickness and magnification. (author)