Real-time Tumor Localization and Guidance for Radiotherapy Using US and MR

The goal of radiotherapy treatment of cancer is to cure or locally control the disease while minimizing complications to healthy tissue. Given the complexity of tumor and normal tissue response to radiation, precise and accurate delivery of absorbed dose distributions, within known tolerances, is necessary to achieve the maximum therapeutic ratio. The complex treatment process of radiotherapy introduces geometrical uncertainties including respiratory induced tumor motion. The goal of this research is to develop and validate a novel image-guidance technique to directly track tumor motion using a 4-dimensional (4D) planar ultrasound (US) transducer during radiation therapy that is coupled to a pre-treatment calibration training image set consisting of a simultaneous 4D ultrasound and 4D magnetic resonance imaging (MRI) acquisition. The image sets will be rapidly matched using advanced image and signal processing algorithms, allowing the display of virtual MR images of the tumor/organ motion in real-time from an ultrasound acquisition.