Optical fibre dosimetry in external beam radiotherapy: Measurements and Monte Carlo simulation

The introduction of new radiation therapy treatment techniques such as intensity modulated radiotherapy and volumetric modulated arc therapy cause well established dosimetry systems to be extended to their capability limits. Optical fibre dosimetry systems offer several advantages over conventional dosimeters for real time dosimetry. This thesis considered the use of a novel inorganic scintillation detector based on a terbium doped gadolinium oxysulphide inorganic scintillator. Essential dosimetry characterisation of the inorganic scintillation detector system for external beam radiotherapy was evaluated. Results obtained demonstrated promising characteristics when used in external beam radiation therapy settings. However, the system overestimated the dose when measuring percentage depth dose and lateral dose profiles. The contribution of Cerenkov radiation and the absorbed-dose energy dependence to the overall signal measured with the inorganic scintillation detector system was also considered in this work. To achieve this, an accurate Cerenkov removal technique using the hyperspectral approach and accurate Monte Carlo model of the linear accelerator was used. Results obtained suggest mechanisms other than the stem effect and the absorbed-dose energy dependence influence the response of the inorganic scintillation detector system at depth.

Funder

Ministry of Education – Kingdom of Saudi Arabi

Publisher

NUI Galway

Rights

Attribution-NonCommercial-NoDerivs 3.0 Ireland

cbn

Collections

University of Galway Theses (PhD Theses)