title: Quality and dose optimization in hand computed radiography.
abstract: The objective of the present study was to optimize a radiographic technique for hand examinations using a computed radiography (CR) system and demonstrate the potential for dose reductions compared with clinically established technique. An exposure index was generated from the optimized technique to guide operators when imaging hands. Homogeneous and anthropomorphic phantoms that simulated a patient's hand were imaged using a CR system at various tube voltages and current settings (40-55 kVp, 1.25-2.8 mAs), including those used in clinical routines (50 kVp, 2.0 mAs) to obtain an optimized chart. The homogeneous phantom was used to assess objective parameters that are associated with image quality, including the signal difference-to-noise ratio (SdNR), which is used to define a figure of merit (FOM) in the optimization process. The anthropomorphic phantom was used to subjectively evaluate image quality using Visual Grading Analysis (VGA) that was performed by three experienced radiologists. The technique that had the best VGA score and highest FOM was considered the gold standard (GS) in the present study. Image quality, dose and the exposure index that are currently used in the clinical routine for hand examinations in our institution were compared with the GS technique. The effective dose reduction was 67.0%. Good image quality was obtained for both techniques, although the exposure indices were 1.60 and 2.39 for the GS and clinical routine, respectively.
authors.affiliation: Dept of Physics and Biophysics, Biosciences Institute of Botucatu, São Paulo State University, Distrito de Rubião Junior S/N, Botucatu, São Paulo 18618-000, Brazil. Electronic address: analuiza@ibb.unesp.br.
authors.forename: A L M
authors.initials: ALM
authors.lastname: Pavan
authors.affiliation: Dept of Physics and Biophysics, Biosciences Institute of Botucatu, São Paulo State University, Distrito de Rubião Junior S/N, Botucatu, São Paulo 18618-000, Brazil. Electronic address: allan@ibb.unesp.br.
authors.forename: A F F
authors.initials: AFF
authors.lastname: Alves
authors.affiliation: Brasilian Center of Physics Research -CBPF-MCT, Rio de Janeiro 22290-180, Brazil. Electronic address: sbd@cbpf.br.
authors.forename: S B
authors.initials: SB
authors.lastname: Duarte
authors.affiliation: Dept of Physics and Biophysics, Biosciences Institute of Botucatu, São Paulo State University, Distrito de Rubião Junior S/N, Botucatu, São Paulo 18618-000, Brazil. Electronic address: guigiacomini92@aluno.ibb.unesp.br.
authors.forename: G
authors.initials: G
authors.lastname: Giacomini
authors.affiliation: Dept of Orthopedics and Traumatology, Botucatu Medical School, São Paulo State University, Distrito de Rubião Junior S/N, Botucatu, São Paulo 18618-000, Brazil. Electronic address: tsarden@fmb.unesp.br.
authors.forename: T
authors.initials: T
authors.lastname: Sardenberg
authors.affiliation: Dept of Physics and Biophysics, Biosciences Institute of Botucatu, São Paulo State University, Distrito de Rubião Junior S/N, Botucatu, São Paulo 18618-000, Brazil. Electronic address: jmiranda@ibb.unesp.br.
authors.forename: J R A
authors.initials: JRA
authors.lastname: Miranda
authors.affiliation: Dept of Tropical Diseases and Diagnostic Imaging, Botucatu Medical School, Univ Estadual Paulista, Distrito de Rubião Junior S/N, Botucatu, São Paulo 18618-000, Brazil. Electronic address: drpina@fmb.unesp.br.
authors.forename: D R
authors.initials: DR
authors.lastname: Pina
mesh_terms: D006225:Hand / Q000000981:diagnostic imaging*; D006801:Humans; D019047:Phantoms, Imaging; D011786:Quality Control; D011829:Radiation Dosage; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Figure of merit; Image optimization; Phantom; Visual Grading Analysis