Original paper Gamma camera calibrations for the Italian multicentre study for lesion dosimetry in 223 Ra therapy of bone metastases Massimiliano Pacilio a,⇑ , Bartolomeo Cassano b , Rosanna Pellegrini c , Elisabetta Di Castro d , Alessandra Zorz e , Giuseppe De Vincentis d , Guido Ventroni f , Lucio Mango f , Stefano Giancola g , Mahila Ferrari h , Marta Cremonesi i , Claudia Bianchi j , Giorgio Virotta k , Claudia Carbonini l , Patrizia Cesana m , Cristian Fulcheri n , Valentina Reggioli n , Alessandra Ricci o , Edoardo Trevisiol p , Silvia Anglesio p , Roberto Pani q a Department of Medical Physics, Azienda Ospedaliera Universitaria Policlinico Umberto I, Viale del Policlinico 155, 00161 Rome, Italy b Postgraduate School of Medical Physics, ‘‘Sapienza” University of Rome, Piazzale Aldo Moro no. 5, 00185 Rome, Italy c Department of Molecular Medicine, ‘‘Sapienza” University of Rome, Viale Regina Elena 291, 00161 Rome, Italy d Department of Radiological, Oncological and Anatomo Pathological Sciences, ‘‘Sapienza” University of Rome, Viale del Policlinico 155, 00161 Rome, Italy e Department of Medical Physics, Veneto Institute of Oncology IOV – IRCCS, Via Gattamelata 64, 35128 Padua, Italy f Department of Nuclear Medicine, Azienda Ospedaliera San Camillo Forlanini, Circonvallazione Gianicolense 87, 00152 Rome, Italy g Department of Medical Physics, Azienda Sanitaria Locale Latina, Via Canova 3, 04100 Latina, Italy h Department of Medical Physics, Istituto Europeo di Oncologia, Via Giuseppe Ripamonti 435, 20141 Milan, Italy i Radiation Research Unit, Istituto Europeo di Oncologia, Via Giuseppe Ripamonti 435, 20141 Milan, Italy j Department of Medical Physics, ASST Papa Giovanni XXIII, Piazza OMS 1, 24127 Bergamo, Italy k Department of Nuclear Medicine, ASST Papa Giovanni XXIII, Piazza OMS 1, 24127 Bergamo, Italy l Department of Medical Physics, Ospedale Niguarda, P.zza Ospedale Maggiore 3, 20162 Milan, Italy m Department of Medical Physics, Azienda Ospedaliera Universitaria Città della Salute e della Scienza di Torino, C.so Bramante 88, 10126 Turin, Italy n Department of Medical Physics, Azienda Ospedaliera di Perugia – Ospedale S. Maria della Misericordia, S. Andrea delle Fratte, 06156 Perugia, Italy o Department of Medical Physics, Azienda Sanitaria Locale Viterbo, Via Enrico Fermi 15, 01100 Viterbo, Italy p Department of Radiotherapy, Azienda Ospedaliero-Universitaria San Luigi Gonzaga, Regione Gonzole 10, 10043 Orbassano, Turin, Italy q Department of Medico-Surgical Sciences and Biotechnologies, ‘‘Sapienza” University of Rome, Corso della Repubblica 79, 04100 Latina, Italy article info Article history: Received 28 December 2016 Received in Revised form 20 March 2017 Accepted 19 April 2017 Available online xxxx Keywords: 223 Ra-dichloride Radionuclide therapy Dosimetry Calibration abstract Purpose: The aim was to calibrate gamma cameras in the framework of the Italian multicentre study for lesion dosimetry in 223 Ra therapy of bone metastases. Equipments of several manufacturers and different models were used. Methods: Eleven gamma cameras (3/8- and 5/8-inch crystal) were used, acquiring planar static images with double-peak (82 and 154 keV, 20% wide) and MEGP collimator. The sensitivity was measured in air, varying source-detector distance and source size. Transmission curves were measured, calculating the parameters used for attenuation/scatter correction with the pseudo-extrapolation number method, and assessing their variations with the source size. Results: Values of the calibration factor (geometric mean of both detector sensitivities) ranged from 41.1 to 113.9 cps/MBq. For the smallest source (diameter of 3.5 cm), the calibration factor decrease ranged from À30% to À4%, highlighting the importance of partial volume effects according to the equipment involved. The sensitivity variation with the source-detector distance, with respect to the 15 cm-value, reached 10% (in absolute value) in the range 5–30 cm, but fixing the distance between the two heads, the calibration factor variation with the distance from the midline was within 3.6%. Appreciable variation of the transmission curves with the source size were observed, examining the results obtained with six gamma cameras. Conclusion: Assessments of sensitivity and transmission curve variations with source size should be reg- ularly implemented in calibration procedures. The results of this study represent a useful compendium to check the obtained calibrations for dosimetric purposes. Ó 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ejmp.2017.04.019 1120-1797/Ó 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: M.Pacilio@policlinicoumberto1.it (M. Pacilio). Physica Medica xxx (2017) xxx–xxx Contents lists available at ScienceDirect Physica Medica journal homepage: http://www.physicamedica.com Please cite this article in press as: Pacilio M et al. Gamma camera calibrations for the Italian multicentre study for lesion dosimetry in 223 Ra therapy of bone metastases. Phys. Med. (2017), http://dx.doi.org/10.1016/j.ejmp.2017.04.019