A Monte Carlo based phase space model for quality assurance of intensity modulated radiotherapy incorporating leaf specific characteristics

Randi F. Aaronson, John J. DeMarco, Indrin J. Chetty, Timothy D. Solberg

Research output: Contribution to journalArticle

24 Scopus citations


Dose calculations for intensity modulated radiation therapy (IMRT) require an accurate description of the radiation field defined by the multileaf collimator. A previously developed Monte Carlo phase space model has been modified to provide accurate dose verification for IMRT treatments on a Novalis linear accelerator. We have incorporated into the model the effects of the multileaf collimator geometry, including leaf transmission, interleaf leakage, the rounded leaf tips and the effects of leaf sequencing, as well as the beam divergence and energy variation across the field. The modified source model was benchmarked against standard depth dose and profile measurements, and the agreement between the calculation and measurement is within the AAPM Task Group No. 53 criteria for all benchmark fields used. Film dosimetry was used to evaluate the model for IMRT sequences and plans, and the ability of the model to account for leaf sequencing effects is also demonstrated.

Original languageEnglish (US)
Pages (from-to)2952-2958
Number of pages7
JournalMedical Physics
Issue number12
Publication statusPublished - Dec 1 2002



  • IMRT treatment plan verification
  • Intensity modulated radiotherapy
  • Monte Carlo
  • Multileaf collimator

ASJC Scopus subject areas

  • Biophysics

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