Stereotactic radiosurgery with several static conformal beams shaped by a micro multileaf collimator (muMLC) is used for treating small irregularly shaped brain lesions. Specific requirements for this technique are a precise localization and positioning of the target (1mm) and a precise (1mm) and numerically accurate (+/-5%) dose delivery. In this work, a pencil beam algorithm based treatment planning software BrainScan 5.2 (Brainlab, Germany) is validated against measurements (diode, radiographic films) and Monte Carlo simulations (BEAMnrc and XVMC codes). The latter is required because of difficulties in obtaining precise and accurate dose measurements for small fields. A dedicated muMLC component module for the BEAMnrc code was developed as part of this project. Results show that Monte Carlo calculations agree with measured dose distributions to within 2% and/or 1 mm except for field sizes smaller than 1.2 cm where agreement is within 5% due to uncertainties in measured output factors. Comparison with the pencil beam algorithm calculations were performed for square and irregularly shaped fields at different incidence angles on rectangular and humanoid homogeneous phantoms. Results show that the pencil beam algorithm is suitable for radiosurgery although some differences were found in the comparison of interleaf leakage and beam profile penumbras.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.81266 |
| Date | January 2004 |
| Creators | Bélec, Jason |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Medical Radiation Physics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 002166660, proquestno: AAIMR06376, Theses scanned by UMI/ProQuest. |
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