Improved Deep Thermal Rehabilitation System with Temperature Measurement Function Using Ultrasound Images

Abstract

This paper describes an improved deep thermal osteoarthritis (OA) rehabilitation system which has a temperature distribution measurement system. In a previous study, we developed a resonant cavity applicator for treating OA and proved that this system was able to heat the knee joint more effectively than other methods; however, this heating system did not have a temperature measurement function. Meanwhile, in a different study, we developed a method using ultrasound imaging techniques to calculate temperature distributions inside the human body. In consideration of clinical application of this applicator, it is necessary to be able to measure the temperature of human tissue during heating. With our applicator, the most important thing is to create an electromagnetic resonant mode deep inside the cavity. Unfortunately, because of electromagnetic interference, we could not utilize an ultrasound imaging probe inside the cavity during heating. To overcome this critical problem, we developed a heating system with a new temperature measurement system. We designed an original jig made of PTFE and developed the remote controllable robotic arm to properly position the probe to take ultrasound images as precisely as possible. Furthermore, the resonant cavity applicator was modified so that it was able to house the ultrasound imaging probe during the heating treatment. In this paper, we first evaluate the performance of the jig by comparing displacement vector distributions. Second, we discuss the results of a heating experiment using this prototype applicator. From our results, it was found that our thermal rehabilitation system with the added temperature measurement function would be useful in clinics for treating osteoarthritis inside the knee joint.