A new method for evaluation of slice sensitivity profiles (SSPz) for spatial variation in 64-channel MSCT

The purpose of this study is to evaluate Slice- sensitive profile on Z-axis (SSPz) at any point in XY plane of multi-slice helical CT (MSCT) by new method that we are proposing. It is very important to understand MSCT physical property to provide high-integrity information and get the best possible images. Quality evaluation around the images has been gaining more importance by needs of proof diversity on evaluation of CT physical property. However, in conventional method of image quality edge of the images, we had some unignorable data variation in every measurement. Considering the development, we assumed that in acquiring helical, the relative position of tube trajectory for the measuring object becomes the problem. Setting the proper scan interval and acquiring the data continuously, we devised the method for property evaluation with controlling tube trajectory. We obtained SSPZ in multiple positions and measured full width at half maximum (FWHM) distribution in axial plane. As a result, we found periodic variation in FWHM especially around the images. The degree of the variation changes depends on helical pitch (HP). If HP is small, the variation is also small, and if HP become larger, the variation also become larger. We figured out the variation in SSPz and FWHM planes through the method that we proposed.