Assessing Inter and Intrafraction Uncertainties in Adult Brain Cancer Patients Using 2D/3D Kv and CBCT Imaging

METHOD:2D/3D kV imaging and CBCT data using 6 degrees of freedom (6DoF) were compared to evaluate inter and intrafraction motion. RESULTS:Results showed that intrafraction errors were low and interfraction levels were within institutional protocols. CONCLUSION:Confidence was given to use low dose 2D/3D kV imaging to confirm daily patient set up errors, and to use pre-treatment CBCT only once weekly for additional imaging information. IMPLICATIONS FOR PRACTICE:Further research is necessary to assess other uncertainties, to enable the calculation of a margin and determining the feasibility of further reduction of this.