SU‐E‐T‐365: IMRT Monte Carlo Dose Calculations for a Novalis TX LINAC Equipped with HD‐120 MLC

l. Vazquez Quino, Sotirios Stathakis, A. Gutierrez, C. Esquivel, Nikos Papanikolaou

Research output: Contribution to journalArticlepeer-review


Purpose: To investigate the accuracy of a Monte Carlo dose calculation engine for IMRT using a Novalis Tx LINAC with the HD‐120 MLC. Methods: PDD and beam profiles ranging from 1×1 to 20×20 cm2 were calculated and compared against measured data in water to commission the LINAC built on the BEAMNRC platform. An in‐house, MATLAB‐based software was used to extract the parameters needed for the MC simulation from the DICOM‐RT plan and create input files for the MCSim egs4 Monte Carlo code. MCSim egs4 software was used to simulate the IMRT treatment plans in a cylindrical solid‐water phantom and ultimately used to compute the dose. In‐house software using a MATLAB platform was utilized to convert the 3D dose file obtained from the Monte Carlo simulation to a universal file which can be read on the RIT Software platform. Within RIT, the MC and treatment planning system (TPS) dose calculations could be compared. Results: 5 IMRT plan simulations were performed and good agreement results were achieved for TPS and MC dose comparison. Gamma analysis with a 3% dose and 3 mm DTA criteria shows a mean gamma index value of 92% for the cases studied. Conclusions: Based on our preliminary results, the Monte Carlo based Novalis Tx linear accelerator and the MCSim simulations of the IMRT treatments on a cylindrical phantom demonstrate good accuracy with regards to the treatment planning dose calculation.

Original languageEnglish (US)
Pages (from-to)3788
Number of pages1
JournalMedical physics
Issue number6
StatePublished - Jun 2012

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging


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