Basic Study of 3-D Non-Invasive Measurement of Temperature Distribution Using Ultrasound Images during FUS Heating

A R T I C L E I N F O A B S T R A C T Article history: Received: 16 September, 2020 Accepted: 01 December, 2020 Online: 16 December, 2020 High Intensity Focused Ultrasound (HIFU) was widely used for treating tumors noninvasively. In this treatment, ultrasound is focused on the target volume inside the human body to ablate cancerous tissues and Magnetic Resonance Imaging (MRI) is mainly used to grasp the target position and to measure the temperature distributions around the target. However, MRI is very expensive, and a large space is required. In this paper, we presented a method for measuring the temperature distribution using an ultrasound diagnostic device, which is inexpensive and commonly used in many clinics, and actually showed the results of heating experiments on a human shaped agar phantom. The proposed method for measuring the temperature distribution around the heated target was conducted by performing image processing on two ultrasound images before and after heating. Furthermore, it was confirmed that it was possible to grasp the three-dimensional temperature distribution from the images in multiple layers. The effectiveness of the temperature distribution measurement results by the proposed method was shown by comparing the temperature measurement results with the infrared thermal camera. The error between the results was approximately 1 °C. It was found that the non-invasive measurement method of the three-dimensional temperature distribution around the target volume using the ultrasound images was useful for effective HIFU treatments.