Technical notes Quality and dose optimization in hand computed radiography A.L.M. Pavan a , A.F.F. Alves a , S.B. Duarte b , G. Giacomini a , T. Sardenberg c , J.R.A. Miranda a , D.R. Pina d, * a Dept of Physics and Biophysics, Biosciences Institute of Botucatu, S~ ao Paulo State University, Distrito de Rubi~ ao Junior S/N, Botucatu, S~ ao Paulo 18618-000, Brazil b Brasilian Center of Physics Research -CBPF-MCT, Rio de Janeiro 22290-180, Brazil c Dept of Orthopedics and Traumatology, Botucatu Medical School, S~ ao Paulo State University, Distrito de Rubi~ ao Junior S/N, Botucatu, S~ ao Paulo 18618-000, Brazil d Dept of Tropical Diseases and Diagnostic Imaging, Botucatu Medical School, Univ Estadual Paulista, Distrito de Rubi~ ao Junior S/N, Botucatu, S~ ao Paulo 18618-000, Brazil article info Article history: Received 7 April 2015 Received in revised form 26 May 2015 Accepted 15 June 2015 Available online xxx Keywords: Phantom Figure of merit Visual Grading Analysis Image optimization 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 pa- tient's hand were imaged using a CR system at various tube voltages and current settings (40e55 kVp, 1.25e2.8 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. © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved. Introduction Many disease processes are manifested in the small bones of the hands, wrists, and associated soft tissues [1,2]. Several diagnostic decisions depend on detecting the details and image contrast of interfaces in the hand and wrist. The early detection, diagnosis, and continuous evaluation of disease states are essential for successful treatment [1,2]. Radiography is the first choice for the evaluation of diseases of the hands, and other image techniques are rarely used to establish diagnosis and treatment. Therefore, the image quality of X-ray examinations is essential. Homogeneous phantoms are widely used in image quality optimization to determine the optimal technique and establish protocols for clinical routines while ensuring maximal image quality with as low as reasonably achievable (ALARA) doses [3,4]. Such phantoms are constructed of tissue-equivalent materials to simulate the absorption and scatter of the X-ray beam in the body. These phantoms are generally made with polymethyl methacrylate (acrylic) and aluminum. Numerous homogeneous phantoms have been constructed for different anatomical regions, such as the chest, abdomen, lumbar spine, skull, and extremities [3e5]. With technical advances from analog to digital systems, tech- niques that have been traditionally considered optimum for analog systems may no longer be considered optimal for digital systems [6,7]. Operators base their choice of technique on trial and error * Corresponding author. Prof. Montenegro Avenue, Rubi~ ao Junior District, Botu- catu, S~ ao Paulo 18618-970, Brazil. Tel.: þ55 1438116088; fax: þ55 1438159898. E-mail addresses: analuiza@ibb.unesp.br (A.L.M. Pavan), allan@ibb.unesp.br (A.F.F. Alves), sbd@cbpf.br (S.B. Duarte), guigiacomini92@aluno.ibb.unesp.br (G. Giacomini), tsarden@fmb.unesp.br (T. Sardenberg), jmiranda@ibb.unesp.br (J.R.A. Miranda), drpina@fmb.unesp.br (D.R. Pina). Contents lists available at ScienceDirect Physica Medica journal homepage: http://www.physicamedica.com http://dx.doi.org/10.1016/j.ejmp.2015.06.010 1120-1797/© 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved. Physica Medica xxx (2015) 1e5 Please cite this article in press as: Pavan ALM, et al., Quality and dose optimization in hand computed radiography, Physica Medica (2015), http:// dx.doi.org/10.1016/j.ejmp.2015.06.010