Open AccessThe commissioning and validation of Monaco treatment planning system on an Elekta Versa HD linear accelerator
Author(s) -
Snyder Jeffrey E.,
Hyer Daniel E.,
Flynn Ryan T.,
Boczkowski Amanda,
Wang Dongxu
Publication year - 2019
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1002/acm2.12507
Subject(s) - linear particle accelerator , monte carlo method , ionization chamber , physics , radiation treatment planning , beam (structure) , photon , optics , computational physics , nuclear medicine , radiation , radiation therapy , mathematics , ion , ionization , medicine , statistics , radiology , quantum mechanics
Accurate beam modeling is essential to help ensure overall accuracy in the radiotherapy process. This study describes our experience with beam model validation of a Monaco treatment planning system on a Versa HD linear accelerator. Data were collected such that Monaco beam models could be generated using three algorithms: collapsed cone ( CC ) and photon Monte Carlo ( MC ) for photon beams, and electron Monte Carlo ( eMC ) for electron beams. Validations are performed on measured percent depth doses ( PDD s) and profiles, for open‐field point‐doses in homogenous and heterogeneous media, and for obliquely incident electron beams. Gamma analysis is used to assess the agreement between calculation and measurement for intensity modulated radiation therapy ( IMRT ) and volumetric modulated arc therapy ( VMAT ) plans, including volumetric modulated arc therapy for stereotactic body radiation therapy ( VMAT SBRT ). For all relevant conditions, gamma index values below 1 are obtained when comparing Monaco calculated PDD s and profiles with measured data. Point‐doses in a water medium are found to be within 2% agreement of commissioning data in 99.5% and 98.6% of the points computed by MC and CC , respectively. All point‐dose calculations for the eMC algorithm in water are within 4% agreement of measurement, and 92% of measurements are within 3%. In heterogeneous media of air and cortical bone, both CC and MC yielded better than 3% agreement with ion chamber measurements. eMC yielded 3% agreement to measurement downstream of air with oblique beams of up to 27°, 5% agreement distal to bone, and within 4% agreement at extended source to surface distance ( SSD ) for all electron energies except 6 MeV. The 6‐MeV point of measurement is on a steep dose gradient which may impact the magnitude of discrepancy measured. The average gamma passing rate for IMRT / VMAT plans is 96.9% (±2.1%) and 98.0% (±1.9%) for VMAT SBRT when evaluated using 3%/2 mm criteria. Monaco beam models for the Versa HD linac were successfully commissioned for clinical use.