title: Modelling optical scattering artefacts for varying pathlength in a gel dosimeter phantom.
abstract: A gelatin phantom containing an optically scattering funnel-shaped region of elevated optical density (OD) was used to examine light-scattering-induced artefacts in a cone-beam optical CT scanner used for gel dosimetry. To simulate polymer gel dosimeters, the opacity was introduced by adding a colloidal scatterer to the gelatin. Scatter results in an underestimate of OD (hence dose). In line profiles of OD taken from 3D reconstructions of the funnel, those profiles with a long pathlength through high OD regions exhibited a 'dishing' (or 'cupping') artefact, while those of short pathlength exhibited the opposite effect-'doming'. These phenomena are accounted for by a model that includes the effect of stray, scattered light.
authors.affiliation: Department of Radiation Oncology, Prince of Wales Hospital, Randwick, NSW 2031, Australia. s.bosi@physics.usyd.edu.au
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Bosi
authors.forename: Saxby
authors.initials: S
authors.lastname: Brown
authors.forename: Sarvenaz
authors.initials: S
authors.lastname: Sarabipour
authors.forename: Yves
authors.initials: Y
authors.lastname: De Deene
authors.forename: Clive
authors.initials: C
authors.lastname: Baldock
mesh_terms: D055592:Biophysical Phenomena; D005780:Gelatin; D005782:Gels; D006801:Humans; D021621:Imaging, Three-Dimensional; D008027:Light; D008962:Models, Theoretical; D019047:Phantoms, Imaging / Q000706:statistics & numerical data; D011857:Radiographic Image Interpretation, Computer-Assisted; D011874:Radiometry / Q000295:instrumentation* / Q000706:statistics & numerical data; D012542:Scattering, Radiation; D014057:Tomography, X-Ray Computed
chemical_list: D005782:Gels; D005780:Gelatin