Modelling the x-ray source for the Australian MRI-Linac

Authors

Natalia Roberts, University of Wollongong, Ingham Institute for Applied Medical ResearchFollow
Bradley M. Oborn, University of Wollongong, Wollongong HospitalFollow
U Jelen, Ingham Institute For Applied Medical Research
B Dong, Ingham Institute For Applied Medical Research
Jarrad Begg, Ingham Institute For Applied Medical Research, Liverpool and Macarthur Cancer Therapy Centres, University of New South Wales
Armia George, Liverpool and Macarthur Cancer Therapy Centres
Saree Alnaghy, University of Wollongong, Ingham Institute for Applied Medical ResearchFollow
Trent Causer, University of Wollongong, Wollongong Hospital, Ingham Institute for Applied Medical ResearchFollow
Thahabah Alharthi, University of Sydney, Ingham Institute for Applied Medical Research
Lois C. Holloway, University of Wollongong, Ingham Institute for Applied Medical Research, Wollongong Hospital, Liverpool and Macarther Cancer Therapy Centre, University of New South WalesFollow
Peter E. Metcalfe, University of Wollongong, Ingham Institute for Applied Medical ResearchFollow

RIS ID

135222

Publication Details

Roberts, N., Oborn, B., Jelen, U., Dong, B., Begg, J., George, A., Alnaghy, S. J., Causer, T., Alharthi, T., Holloway, L. & Metcalfe, P. (2019). Modelling the x-ray source for the Australian MRI-Linac. Journal of Physics: Conference Series, 1154 (Congerence 1), 1-4.

Abstract

MRI-guided radiotherapy allows real-time imaging during treatment however the magnetic field influences the dose distribution in the patient. An accurate model of the radiation beam and the encompassing magnetic field is important to predict dosimetry changes. The purpose of this work is to develop a Monte Carlo model of the Australian MRI-Linac to be used as input into a dose calculation tool for treatment planning. The Australian MRI-Linac is a 1 T inline system with a 6MV flattening filter free photon beam. Commissioning measurements were undertaken both with and without the magnetic field present, PDDs and profiles were used to develop a model with the Geant4 toolkit. To date the model at 0 T matches within ± 2% of measured data. Ongoing work involves measurements at 1 T at various linac to MRI isocentre distances, the magnetic field model at each configuration is also under development.