title: Comparison between two treatment planning systems for volumetric modulated arc therapy optimization for prostate cancer.
abstract: OBJECTIVE
  To investigate the performances of two commercial treatment planning systems (TPS) for Volumetric Modulated Arc Therapy (VMAT) optimization regarding prostate cancer. The TPS were compared in terms of dose distributions, treatment delivery parameters and quality control results.
  
  
  METHODS
  For ten patients, two VMAT plans were generated: one with Monaco TPS (Elekta) and one with Pinnacle TPS (Philips Medical Systems). The total prescribed dose was 78 Gy delivered in one 360° arc with a Synergy(®) linear accelerator equipped with a MLCi2(®).
  
  
  RESULTS
  VMAT with Monaco provided better homogeneity and conformity indexes but lower mean dose to PTVs than Pinnacle. For the bladder wall (p = 0.019), the femoral heads (p = 0.017), and healthy tissues (p = 0.005), significantly lower mean doses were found using Monaco. For the rectal wall, VMAT with Pinnacle provided a significantly (p = 0.047) lower mean dose, and lower dose into 50% of the volume (p = 0.047) compared to Monaco. Despite a greater number of monitor units (factor 1.5) for Monaco TPS, the total treatment time was equivalent to that of Pinnacle. The treatment delivery parameter analysis showed larger mean MLC area for Pinnacle and lower mean dose rate compared to Monaco. The quality control results gave a high passing rate (>97.4%) for the gamma index for both TPS but Monaco provided slightly better results.
  
  
  CONCLUSIONS
  For prostate cancer patients, VMAT treatment plans obtained with Monaco and Pinnacle offered clinically acceptable dose distributions. Further investigations are in progress to confirm the performances of the two TPS for irradiating more complex volumes.
authors.affiliation: Radiation Oncology Department, Centre Eugène Marquis, Rennes, France; Université de Rennes 1, LTSI, France; INSERM, U1099, France. Electronic address: c.lafond@rennes.unicancer.fr.
authors.forename: Caroline
authors.initials: C
authors.lastname: Lafond
authors.affiliation: Radiation Oncology Department, Centre Léon Bérard, Lyon, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Gassa
authors.affiliation: Institut of Physics of Rennes, IPR/UMR CNRS 6251, University of Rennes I, Rennes, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Odin
authors.affiliation: Université de Rennes 1, LTSI, France; INSERM, U1099, France.
authors.forename: Gaël
authors.initials: G
authors.lastname: Dréan
authors.affiliation: Radiation Oncology Department, Centre Eugène Marquis, Rennes, France.
authors.forename: Justine
authors.initials: J
authors.lastname: Even
authors.affiliation: Radiation Oncology Department, Centre Eugène Marquis, Rennes, France; Université de Rennes 1, LTSI, France; INSERM, U1099, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: De Crevoisier
authors.affiliation: Radiation Oncology Department, Centre Léon Bérard, Lyon, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Pommier
authors.affiliation: Radiation Oncology Department, Centre Eugène Marquis, Rennes, France; Université de Rennes 1, LTSI, France; INSERM, U1099, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Manens
authors.affiliation: Radiation Oncology Department, Centre Léon Bérard, Lyon, France.
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Biston
mesh_terms: D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011785:Quality Assurance, Health Care; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*
keywords: Monaco; Pinnacle; Prostate cancer; VMAT