title: A multi-phased study of optimisation methodologies and radiation dose savings for head CT examinations.
abstract: The impact of optimisation methods on dose reductions for head computerised tomography was undertaken in three phases for two manufacturer models. Phase 1: a Catphan(®)600 was employed to evaluate protocols where the impact of parameter manipulation on dose and image quality was gauged by psychophysical measurements of contrast and spatial resolution in terms of contrast discs and line pairs. mA, kV and pitch were systematically altered until the optimisation threshold was identified. Phantom studies provide dose comparisons during optimisation but lack anatomical detail. Phase 2: optimised protocols were tested on a porcine model permitting further dose reductions over phantom findings providing anatomical structures for image quality evaluation using relative visual grading analysis of anatomical criteria. Phase 3: patient images using pre- and post-optimised protocols were clinically audited using visual grading characteristic analysis and ordinal regression analysis providing a robust analysis of image quality data prior to clinical implementation.
authors.affiliation: Department of Radiography, Faculty of Health Sciences, University of Malta, Msida, Malta francis.zarb@um.edu.mt.
authors.forename: Francis
authors.initials: F
authors.lastname: Zarb
authors.affiliation: Discipline of Medical Radiation Sciences and Brain and Mind Research Institute, Faculty of Health Sciences, The University of Sydney, Sydney, Australia.
authors.forename: Mark F
authors.initials: MF
authors.lastname: McEntee
authors.affiliation: School of Medicine and Medical Science, Health Science Centre, University College Dublin, Belfield Dublin 4, Ireland.
authors.forename: Louise
authors.initials: L
authors.lastname: Rainford
mesh_terms: D000818:Animals; D006257:Head / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D013552:Swine; D014057:Tomography, X-Ray Computed / Q000379:methods*