Filters for single slice helical image reconstruction in a computed tomography system

Abstract

Filtering algorithms which offer tradeoffs between slice profile widening and the noise and mAs, reduction are described. In one embodiment, the FWHM is adjusted based on the helical pitch to provide a constant reduction of noise. The percentage increase of FWHM is a function of helical pitch as described below in more detail. The amount of projection data used to reconstruct an image is fixed, independent of the helical pitch. In another embodiment, a roughly constant percentage increase of FWHM is maintained while the amount of reduction of mAs or noise decreases as helical pitch increases. The amount of projection data used to reconstruct an image is also a function of helical pitches. The above described filters provide that for various helical pitches, the filter maintains the same amount of mAs or noise reduction, or maintains the same percentage increase of FWHM. Such filters can be implemented without significantly increasing the processing time.

Dependencies are inferred from the claim text.