Stereotactic Ablative Body Radiotherapy (SABR) is an established treatment for both primary and secondary liver malignancies and is a highly effective treatment, but precise dose delivery is challenging due to organ motion. Currently, there is a lack of widely available options for performing real-time tumour localisation to assist with accurate delivery of liver SABR. This study will provide an assessment of the impact of Kilovoltage Intrafraction Monitoring (KIM) as a potential solution for real-time image guidance in liver SABR. It is hoped that this information will improve cancer targeting accuracy and lead to better patient outcomes in the future.