title: Small field output factors evaluation with a microDiamond detector over 30 Italian centers.
abstract: OBJECTIVE
  The aim of the study was a multicenter evaluation of MLC&jaws-defined small field output factors (OF) for different linear accelerator manufacturers and for different beam energies using the latest synthetic single crystal diamond detector commercially available. The feasibility of providing an experimental OF data set, useful for on-site measurements validation, was also evaluated.
  
  
  METHODS
  This work was performed in the framework of the Italian Association of Medical Physics (AIFM) SBRT working group. The project was subdivided in two phases: in the first phase each center measured OFs using their own routine detector for nominal field sizes ranging from 10×10cm2to 0.6×0.6cm2. In the second phase, the measurements were repeated in all centers using the PTW 60019 microDiamond detector.
  
  
  RESULTS
  The project enrolled 30 Italian centers. Micro-ion chambers and silicon diodes were used for OF measurements in 24 and 6 centers respectively. Gafchromic films and TLDs were used for very small field OFs in 3 and 1 centers. Regarding the measurements performed with the user's detectors, OF standard deviations (SD) for field sizes down to 2×2cm2were in all cases <2.7%. In the second phase, a reduction of around 50% of the SD was obtained using the microDiamond detector.
  
  
  CONCLUSIONS
  The measured values presented in this multicenter study provide a consistent dataset for OFs that could be a useful tool for improving dosimetric procedures in centers. The microDiamond data present a small variation among the centers confirming that this detector can contribute to improve overall accuracy in radiotherapy.
authors.affiliation: Medical Physics Unit, Azienda USL Toscana Centro, Firenze, I-50012 Firenze, Italy. Electronic address: serenella.russo@uslcentro.toscana.it.
authors.forename: Serenella
authors.initials: S
authors.lastname: Russo
authors.affiliation: Medical Physics Unit of Radiation Oncology Dept., Humanitas Research Hospital, Milano, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Reggiori
authors.affiliation: IRCCS - Arcispedale Santa Maria Nuova, Reggio Emilia, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Cagni
authors.affiliation: A.O.U. Federico II, Napoli, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Clemente
authors.affiliation: Medical Physics Unit, Azienda USL Toscana Centro, Firenze, I-50012 Firenze, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Esposito
authors.affiliation: SS. Annunziata Hospital, Chieti, Italy.
authors.forename: Maria Daniela
authors.initials: MD
authors.lastname: Falco
authors.affiliation: Dep. of Oncology, Radiation Oncology Unit, University of Torino, Italy.
authors.forename: Christian
authors.initials: C
authors.lastname: Fiandra
authors.affiliation: A.O.U. Città della Salute e della Scienza di Torino, Torino, Italy.
authors.forename: Francesca Romana
authors.initials: FR
authors.lastname: Giglioli
authors.affiliation: INFN - Dipartimento di Ingegneria Industriale, Università di Roma 'Tor Vergata', Roma, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Marinelli
authors.affiliation: Humanitas C.C.O., Catania, Italy.
authors.forename: Carmelo
authors.initials: C
authors.lastname: Marino
authors.affiliation: Department of Medical Physics and Radiation Oncology, IFCA, I-50139 Firenze, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Masi
authors.affiliation: Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti, ENEA-INMRI C R Casaccia, Roma, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Pimpinella
authors.affiliation: A.O. Ordine Mauriziano di Torino, Torino, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Stasi
authors.affiliation: Laboratory of Medical Physics and Expert Systems, Regina Elena Cancer Center IFO, Roma, Italy.
authors.forename: Lidia
authors.initials: L
authors.lastname: Strigari
authors.affiliation: Università degli Studi di Firenze, A.O.U. Careggi-Medical Physics Unit, Firenze, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Talamonti
authors.affiliation: AUSL Piacenza, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Villaggi
authors.affiliation: Medical Physics Unit of Radiation Oncology Dept., Humanitas Research Hospital, Milano, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Mancosu
mesh_terms: D018130:Diamond; D005240:Feasibility Studies; D009010:Monte Carlo Method; D010315:Particle Accelerators; D011874:Radiometry / Q000295:instrumentation*; D012825:Silicon
chemical_list: D018130:Diamond; D012825:Silicon
keywords: Multicenter evaluation; PTW-60019 microDiamond detector; Small field output factor