Feasibility 3D Perfusion Ultrasound for Liver Cancer SABR Planning and Response Evaluation

Primary Objective: The primary objectives of this prospective pilot study is to: 1. determine the feasibility and reproducibility of 3D contrast enhanced ultrasound imaging in liver cancer patients undergoing Stereotactic Ablative Radiotherapy and 2. evaluate whether there are treatment induced early changes in imaging metrics derived from 3D contrast enhanced ultrasound. This study will provide valuable insight as to the potential of baseline and/or early post-treatment 3D ultrasound perfusion characteristics (measurements of blood-flow) of primary and metastatic liver tumors to predict tumor response to Stereotactic Ablative Radiotherapy. The investigators' underlying goal is to assess whether early perfusion changes at 1-7 days after SABR initiation can be used as a non-invasive early biomarker for treatment response assessment. Secondary Objectives: Evaluate the feasibility of contrast-enhanced ultrasound-to-CT fusion by assisting three-dimensional (3D) perfusion ultrasound (US) imaging with optical and electromagnetic tracking of the ultrasound probe on patients with liver cancer that will undergo CT for treatment planning and/or response evaluation.