title: Moving beam helical CT scanning.
abstract: Images generated with helical scanning are degraded by partial volume artifacts caused by an increased slice thickness when compared to conventional computed tomography (CT) scanning. The slice thickness for a helical scan is proportional to the sum of the thickness of the fan of radiation and the distance the patient moves during data acquisition. The authors present a method called moving beam helical scanning (MBHS) which significantly reduces the partial volume artifacts caused by helical scanning. The key element of MBHS is a rotatable collimator that is placed between the X-ray source and the patient. As the patient is translated, the collimator is used to aim the fan on a fixed position in the patient. Once sufficient data are obtained to reconstruct a slice, the collimator is quickly reset to scan a target in the next slice. The authors examined the performance of MBHS by scanning wires and phantoms on a modified scanner. The full-width-at-tenth-maximum of the slice profile at iso-center for MBHS is identical to conventional CT versus a 59% increase for conventional helical scanning. It is concluded that MBHS can be used to obtain the scan rate advantages of helical scanning with image quality comparable to conventional scanning.
authors.affiliation: Analogic Corp., Peabody, MA.
authors.forename: C R
authors.initials: CR
authors.lastname: Crawford
authors.forename: K F
authors.initials: KF
authors.lastname: King
authors.forename: T L
authors.initials: TL
authors.lastname: Toth
authors.forename: H
authors.initials: H
authors.lastname: Hu