title: Commissioning and initial experience with a commercial software for in vivo volumetric dosimetry.
abstract: OBJECTIVE
  Dosimetry Check (DC) (Math Resolutions) is a commercial EPID-based dosimetry software, which allows performing pre-treatment and transit dosimetry. DC provides an independent verification of the treatment, being potentially of great interest due to the high benefits of the in vivo volumetric dosimetry, which guarantee the treatment delivery and anatomy constancy. The aim of this work is to study the differences in dose between DC and the Treatment Planning System (TPS) to establish an accuracy level of the system.
  
  
  METHODS
  DC v.3.8 was used along with Varian Clinac iX accelerator equipped with EPID aS1000 and Eclipse v.10.0 with AAA and Acuros XB calculation algorithms. The DC evaluated version is based on a pencil beam calculation algorithm. Various plans were generated over several homogeneous and heterogeneous phantoms. Isocentre point doses and gamma analysis were evaluated.
  
  
  RESULTS
  Total dose differences at the isocentre between DC and TPS for the studied plans are less than 2%, but single field contributions achieve greater values. In the presence of heterogeneities, the discrepancies can reach up to 15%. In transit mode, DC does not consider properly the couch attenuation, especially when there is an air gap between phantom and couch.
  
  
  CONCLUSIONS
  The possibility of this in vivo evaluation and the potentiality of this new system have a very positive impact on improving patient QA. But improvements are required in both calculation algorithm and integration with the record and verify system.
authors.affiliation: Physics Section, Radiotherapy Department, La Fe University and Polytechnic Hospital, E-46026 Valencia, Spain. Electronic address: josegimenoolmos@gmail.com.
authors.forename: J
authors.initials: J
authors.lastname: Gimeno
authors.affiliation: National Dosimetry Centre, E-46009 Valencia, Spain.
authors.forename: M C
authors.initials: MC
authors.lastname: Pujades
authors.affiliation: Physics Section, Radiotherapy Department, La Fe University and Polytechnic Hospital, E-46026 Valencia, Spain.
authors.forename: T
authors.initials: T
authors.lastname: García
authors.affiliation: Physics Section, Radiotherapy Department, La Fe University and Polytechnic Hospital, E-46026 Valencia, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Carmona
authors.affiliation: Physics Section, Radiotherapy Department, La Fe University and Polytechnic Hospital, E-46026 Valencia, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Lliso
authors.affiliation: Physics Section, Radiotherapy Department, La Fe University and Polytechnic Hospital, E-46026 Valencia, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Palomo
authors.affiliation: Physics Section, Radiotherapy Department, La Fe University and Polytechnic Hospital, E-46026 Valencia, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Candela-Juan
authors.affiliation: Radiotherapy Department, Hospital Clinica Benidorm, E-03501 Benidorm, Alicante, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Richart
authors.affiliation: Physics Section, Radiotherapy Department, La Fe University and Polytechnic Hospital, E-46026 Valencia, Spain; Radiotherapy Department, Hospital Clinica Benidorm, E-03501 Benidorm, Alicante, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Perez-Calatayud
mesh_terms: D000465:Algorithms; D006801:Humans; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012984:Software
keywords: Dosimetry check; IMRT-VMAT verification; In vivo dosimetry; Transit dosimetry