title: Evaluation of a bilinear model for attenuation correction using CT numbers generated from a parametric method.
abstract: A parametric model is used for the calculation of the CT number of some selected human tissues of known compositions (Hi) in two hybrid systems, one SPECT-CT and one PET-CT. Only one well characterized substance, not necessarily tissue-like, needs to be scanned with the protocol of interest. The linear attenuation coefficients of these tissues for some energies of interest (μ(i)) have been calculated from their tabulated compositions and the NIST databases. These coefficients have been compared with those calculated with the bilinear model from the CT number (μ(B)i). No relevant differences have been found for bones and lung. In the soft tissue region, the differences can be up to 5%. These discrepancies are attributed to the different chemical composition for the tissues assumed by both methods.
authors.affiliation: Medical Physics and Radiation Protection Service, 12 de Octubre University Hospital, Avda. de Córdoba s/n, 28041 Madrid, Spain. Electronic address: luisc.martinez@salud.madrid.org.
authors.forename: L C
authors.initials: LC
authors.lastname: Martinez
authors.affiliation: Radiology Department, Medicine School, Complutense University, Pza. Ramón y Cajal s/n, 28040 Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Calzado
mesh_terms: D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D015233:Models, Statistical; D064847:Multimodal Imaging; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000706:statistics & numerical data; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015899:Tomography, Emission-Computed, Single-Photon / Q000706:statistics & numerical data; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*
keywords: Attenuation correction; Hybrid systems; Stoichiometric calculation