title: Quality assurance of carbon ion and proton beams: A feasibility study for using the 2D MatriXX detector.
abstract: OBJECTIVE
  The quality assurance (QA) procedures in particle therapy centers with active beam scanning make extensive use of films, which do not provide immediate results. The purpose of this work is to verify whether the 2D MatriXX detector by IBA Dosimetry has enough sensitivity to replace films in some of the measurements.
  
  
  METHODS
  MatriXX is a commercial detector composed of 32×32 parallel plate ionization chambers designed for pre-treatment dose verification in conventional radiation therapy. The detector and GAFCHROMIC® films were exposed simultaneously to a 131.44MeV proton and a 221.45MeV/u carbon-ion therapeutic beam at the CNAO therapy center of Pavia - Italy, and the results were analyzed and compared.
  
  
  RESULTS
  The sensitivity MatriXX on the beam position, beam width and field flatness was investigated. For the first two quantities, a method for correcting systematic uncertainties, dependent on the beam size, was developed allowing to achieve a position resolution equal to 230μm for carbon ions and less than 100μm for protons. The beam size and the field flatness measured using MatriXX were compared with the same quantities measured with the irradiated film, showing a good agreement.
  
  
  CONCLUSIONS
  The results indicate that a 2D detector such as MatriXX can be used to measure several parameters of a scanned ion beam quickly and precisely and suggest that the QA would benefit from a new protocol where the MatriXX detector is added to the existing systems.
authors.affiliation: Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria 1, I-10125 Torino, Italy; Dipartimento di Fisica dell'Università di Torino, via P. Giuria 1, I-10125 Torino, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Varasteh Anvar
authors.affiliation: Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria 1, I-10125 Torino, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Attili
authors.affiliation: Centro Nazionale Adroterapia Oncologica (CNAO), Strada Campeggi 53, I-27100 Pavia, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Ciocca
authors.affiliation: Centro Nazionale Adroterapia Oncologica (CNAO), Strada Campeggi 53, I-27100 Pavia, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Donetti
authors.affiliation: Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria 1, I-10125 Torino, Italy; Dipartimento di Fisica dell'Università di Torino, via P. Giuria 1, I-10125 Torino, Italy.
authors.forename: L K
authors.initials: LK
authors.lastname: Fanola Guarachi
authors.affiliation: Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria 1, I-10125 Torino, Italy; Dipartimento di Elettronica e Telecomunicazioni del Politecnico di Torino, Corso Duca degli Abruzzi, 24, I-10129 Torino, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Fausti
authors.affiliation: Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria 1, I-10125 Torino, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Giordanengo
authors.affiliation: Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria 1, I-10125 Torino, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Marchetto
authors.affiliation: Centro Nazionale Adroterapia Oncologica (CNAO), Strada Campeggi 53, I-27100 Pavia, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Molinelli
authors.affiliation: Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria 1, I-10125 Torino, Italy; Dipartimento di Fisica dell'Università di Torino, via P. Giuria 1, I-10125 Torino, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Monaco
authors.affiliation: Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria 1, I-10125 Torino, Italy; Dipartimento di Fisica dell'Università di Torino, via P. Giuria 1, I-10125 Torino, Italy. Electronic address: roberto.sacchi@unito.it.
authors.forename: R
authors.initials: R
authors.lastname: Sacchi
authors.affiliation: Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria 1, I-10125 Torino, Italy; Dipartimento di Fisica dell'Università di Torino, via P. Giuria 1, I-10125 Torino, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Vignati
authors.affiliation: Istituto Nazionale di Fisica Nucleare, sez. di Torino, via P. Giuria 1, I-10125 Torino, Italy; Dipartimento di Fisica dell'Università di Torino, via P. Giuria 1, I-10125 Torino, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Cirio
mesh_terms: D005240:Feasibility Studies; D063193:Heavy Ion Radiotherapy / Q000592:standards*; D061766:Proton Therapy / Q000592:standards*; D011785:Quality Assurance, Health Care; D011874:Radiometry / Q000295:instrumentation*; D011879:Radiotherapy Dosage
keywords: Active beam scanning; MatriXX; Particle therapy; Quality assurance