Dosimetric validation of a commercial Monte Carlo based IMRT planning system.
OBJECTIVE
Recently a commercial Monte Carlo based IMRT planning system (Monaco version 1.0.0) was released. In this study the dosimetric accuracy of this new planning system was validated.


METHODS
Absolute dose profiles, depth dose curves, and output factors calculated by Monaco were compared with measurements in a water phantom. Different static on-axis and off-axis fields were tested at various source-skin distances for 6, 10, and 18 MV photon beams. Four clinical IMRT plans were evaluated in a water phantom using a linear diode detector array and another six IMRT plans for different tumor sites in solid water using a 2D detector array. In order to evaluate the accuracy of the dose engine near tissue inhomogeneities absolute dose distributions were measured with Gafchromic EBT film in an inhomogeneous slab phantom. For an end-to-end test a four-field IMRT plan was applied to an anthropomorphic lung phantom with a simulated tumor peripherally located in the right lung. Gafchromic EBT film, placed in and around the tumor area, was used to evaluate the dose distribution.


RESULTS
Generally, the measured and the calculated dose distributions agreed within 2% dose difference or 2 mm distance-to-agreement. But mainly at interfaces with bone, some larger dose differences could be observed.


CONCLUSIONS
Based on the results of this study, the authors concluded that the dosimetric accuracy of Monaco is adequate for clinical introduction.
Department of Radiation Oncology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam, Groene Hilledijk 301, 3008 AE, The Netherlands. d.grofsmid@erasmusmc.nl
Dennis
D
Grofsmid
Maarten
M
Dirkx
Hans
H
Marijnissen
Evert
E
Woudstra
Ben
B
Heijmen
D000465:Algorithms; D003198:Computer Simulation; D006801:Humans; D008954:Models, Biological; D009010:Monte Carlo Method; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012984:Software