Aim-1: Ultrasound Elasticity Imaging Acquisition. USEI data (both raw US data and B-mode data) will be recorded during standard operative ultrasound imaging used to guide thermal ablative therapy in the operating room. Images will be acquired before, during, and after RFA or MWA therapy. Raw data acquisition will be conducted using a Siemens Antares US scanner (Siemens Medical Solutions USA, Inc. Ultrasound Division, Issaquah, WA) with an ultrasound research interface (URI) to access raw US data. A Siemens VF 10-5 linear array will be used to acquire data using manual handling. Typically, the ultrasound probe is tracked and spatially registered with the coordinate frame of the of the CT images, so the pixels of the B-mode images are known in the coordinate frame of the CT volume. Thus if one localizes the target anatomy in the B-mode images, then the position of the target is automatically known with respect to the CT volume for validation of the performance of the elastography. The tracking beams are standard B-mode pulses (6.67 MHz center frequency, F/1.5 focal configuration, apodized, pulse repetition frequency (PRF) of 10.6 KHz, with a pulse length of 0.3μs). This US device is one of the standard machines available for clinical US.