title: A dosimetric evaluation of the Eclipse AAA algorithm and Millennium 120 MLC for cranial intensity-modulated radiosurgery.
abstract: The aim of this study is to assess the accuracy of a convolution-based algorithm (anisotropic analytical algorithm [AAA]) implemented in the Eclipse planning system for intensity-modulated radiosurgery (IMRS) planning of small cranial targets by using a 5-mm leaf-width multileaf collimator (MLC). Overall, 24 patient-based IMRS plans for cranial lesions of variable size (0.3 to 15.1cc) were planned (Eclipse, AAA, version 10.0.28) using fixed field-based IMRS produced by a Varian linear accelerator equipped with a 120 MLC (5-mm width on central leaves). Plan accuracy was evaluated according to phantom-based measurements performed with radiochromic film (EBT2, ISP, Wayne, NJ). Film 2D dose distributions were performed with the FilmQA Pro software (version 2011, Ashland, OH) by using the triple-channel dosimetry method. Comparison between computed and measured 2D dose distributions was performed using the gamma method (3%/1mm). Performance of the MLC was checked by inspection of the DynaLog files created by the linear accelerator during the delivery of each dynamic field. The absolute difference between the calculated and measured isocenter doses for all the IMRS plans was 2.5% ± 2.1%. The gamma evaluation method resulted in high average passing rates of 98.9% ± 1.4% (red channel) and 98.9% ± 1.5% (blue and green channels). DynaLog file analysis revealed a maximum root mean square error of 0.46mm. According to our results, we conclude that the Eclipse/AAA algorithm provides accurate cranial IMRS dose distributions that may be accurately delivered by a Varian linac equipped with a Millennium 120 MLC.
authors.affiliation: Departamento de Oncología Radioterápica, Hospital Quirón, Barcelona, Spain. Electronic address: jfcdrr@yahoo.es.
authors.forename: Juan Francisco
authors.initials: JF
authors.lastname: Calvo Ortega
authors.affiliation: Departamento de Oncología Radioterápica, Hospital Quirón, Barcelona, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: Moragues
authors.affiliation: Departamento de Oncología Radioterápica, Hospital Quirón, Barcelona, Spain.
authors.forename: Miquel
authors.initials: M
authors.lastname: Pozo
authors.affiliation: Departamento de Oncología Radioterápica, Hospital Quirón, Barcelona, Spain.
authors.forename: Sol San
authors.initials: SS
authors.lastname: José
authors.affiliation: Departamento de Oncología Radioterápica, Hospital Quirón, Barcelona, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Puertas
authors.affiliation: Departamento de Oncología Radioterápica, Hospital Quirón, Barcelona, Spain.
authors.forename: Jaime
authors.initials: J
authors.lastname: Fernández
authors.affiliation: Departamento de Oncología Radioterápica, Hospital Quirón, Barcelona, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Casals
mesh_terms: D000465:Algorithms; D001927:Brain Diseases / Q000601:surgery*; D006801:Humans; D016634:Radiosurgery; D011880:Radiotherapy Planning, Computer-Assisted
keywords: AAA; EBT2; Eclipse; IMRS; Radiosurgery