A new method for absolute accuracy evaluation of a US-guided HIFU system with heterogeneous phantom

High Intensity Focused Ultrasound as a non-invasive treatment method has gaining its popularity in various clinical application. HIFU is usually used with navigation system with which to make pre-operative plan. Our group developed a US-guided HIFU system for breast cancer treatment. In order to precisely remove the tumor region and reduce the damage to the surrounding normal tissue to minimal level, it is important to evaluate the absolute accuracy of the treatment system, i.e. the spatial difference between the planned target region and the actual treated one. However, this task is often hard and there is few related work. In this research, we provide a method to quantitatively evaluate the accuracy of the US-guided HIFU treatment on 2D treatment plane. We use heterogeneous phantom which contains chicken meat surrounded by porcine liver to mimic tumor surrounded by normal tissue, and 3D printed markers to serve as spatial reference. The simulated tumor and simulated surrounding normal tissue as well as the markers are embedded into transparent gel with breast shape. With this setting, the boundary and shape of the treated region can be preserved. Moreover, the planned treatment region on the US image and the actual treated region can be registered into the same reference coordinate frame for comparison. The result demonstrates that the proposed method is capable of evaluating the absolute accuracy of the US-guided HIFU treatment on 2D treatment plane and our US-guided HIFU system has achieved high accuracy.