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Poster — Thur Eve — 73: Dosimetric Performance of Radionics Mini‐MLC on Elekta Synergy S Linear Accelerator: A Monte Carlo Evaluation
Author(s) -
Lahroodi KA,
Heydarian M
Publication year - 2010
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3476178
Subject(s) - isocenter , monte carlo method , linear particle accelerator , nuclear medicine , ionization chamber , physics , collimator , field size , radiosurgery , multileaf collimator , dosimetry , beam (structure) , optics , imaging phantom , mathematics , medicine , ionization , radiation therapy , radiology , ion , statistics , quantum mechanics
This work contributed new information of dosimetric evaluation of Radionics mini‐multileaf collimator (MMLC) attached on the head of an Elekta Synergy S linear accelerator using Monte Carlo simulations. The penumbrae, depth and lateral dose profiles of the Radionics MMLC for the 6 MV photon beams, were determined first time using the EGSnrc‐based Monte Carlo codes (BEAMnrc) verified by measurements. The Monte Carlo modelled MMLC has a maximum field size of 9.6 × 12 cm 2 and 3.8 mm leaf thickness at the isocenter. Monte Carlo verification was carried out using CC13 Wellhofer ionization chamber (cavity volume = 0.13 cm 3 ) and a Wellhofer water tank for measurements. Dosimetric parameters such as the penumbrae, percentage depth doses, the in‐plane and cross‐plane off‐axis dose profiles were measured and calculated for different field sizes and depths. Penumbra widths (80%−20%) for the reference field of 9.6 × 10.4 cm 2 at the isocenter with a depth of 10 cm were 4.8 and 5.1 mm for the leaf‐sides and leaf‐ends, respectively. The corresponding values of penumbrae at depths of 1.5 and 5 cm were 3.6 and 4.2 mm for the leaf‐sides and 3.8 and 4.5 mm for the leaf‐ends. Dosimetric results based on our Monte Carlo model demonstrated excellent agreement to within 1% or 1 mm when compared to measurements. Our Monte Carlo model for the MMLC is expected to benefit the commissioning of the stereotactic radiosurgery planning for the small intracranial and extracranial lesions.