Out-of-Field Dose to the Eye Lens and Cardiac Implantable Electronic Devices (CIEDs) during VMAT of the prostate

Volumetric Modulated Arc Therapy (VMAT) is a new type of Intensity Modulated Radiation Therapy (IMRT) technique as it can deliver a more accurate shape of sculpted 3D dose distribution to the targeted tumour volume in a single 360 degree gantry rotation or multiple sub-arcs. This improvement, however, has not mitigated the problem of doses to normal tissues outside the treated volume. The out-of-field dose associated risks remains high clinical and scientific interests for investigations. A re-evaluation of the eye lens radio-sensitivity by the ICRP 2011 has resulted in a significant reduction of the threshold for lens opacities from 8 Gy to 0.5 Gy. The objective of this thesis study is to investigate the out-of-field doses to critical structures such as eye lens and CIEDs (cardiac implantable electronic devices) such as pacemakers and ICDs during 6 MV VMAT treatment of the prostate.