Surface dose measurements in clinical 6 MeV-X-photon beams : Comparison of Measurements and MC calculations.
No Thumbnail Available
Date
2010-04-18
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Thai Society of Therapeutic Radiology and Oncology - วารสารมะเร็งวิวัฒน์
Abstract
For radiotherapy of superfi cial lesions, but alsoin intensity modulated radiotherapy (IMRT), 6MeV-X-photon beams are preferred, with relativesurface doses, dependent on fi eld size and SSD,of 8 % to 28 %. Depending on absorption materialwithin the beam this values can vary considerable.The infl uence of a block tray, different metals anda new type of transmission detector on surfacedoses as well as on other beam parameters havebeen investigated. The surface doses as well assome other fi eld parameters have been checkedby means of a plane parallel ionization chamber(Markus chamber, type 23 343, PTW-Freiburg,Germany). Because of specifi c design features thereadings have to be corrected, and the results havebeen verifi ed by Monte Carlo (MC) simulations andcalculations: Measurements agreed well withcalculations within Δ ≈ 3 %. So it could be shownfor the used Markus chamber, type 23 343, that theapplied correction function is suitable for open fi eldsas well as for blocked fi elds at different clinical usedSSDs.
Description
Keywords
Citation
Journal of Thai Society of Therapeutic Radiology and Oncology - วารสารมะเร็งวิวัฒน์; Vol. 16 No. 1 January – June 2010; 15 - 19