Development Of Magnetic Resonance Guided Focused Ultrasound Ablation Machine

BACKGROUND:High-intensity focused ultrasound (HIFU) is a new generation of tumor treatment equipment. The equipment machine use ultrasonic transducers to generate high-intensity ultrasound in vitro, which focused on tumor in vivo. Because of the thermal and cavitation effects of ultrasound, the temperature in the focus tissue was raised to600C-1000C. It is non-invasive, accurate, therefore it is considered to be new, safe and efficient means of cancer treatment following surgery, chemotherapy, and radiotherapy by the international medical community.The positioning method is the key factor of safety and efficiency in the HIFU treatment. After using ultrasound scanner positioning method in the previous generation, the latest HIFU system use magnetic resonance (MR) to position generally. The use of magnetic resonance is high field superconducting MR in the world at present, which is expensive, so the actual product is not yet dominate the market. This thesis develop the system of low field home-built permanent MR guided HIFU integration system, which can improve the image quality compared with the ultrasound scanner guided HIFU, and is inexpensive compared with high field MR.OBJECTIVE:This thesis have done so a lot of research on low field home-built permanent MR and HIFU that the two system as one, to achieve a real integration system.MAIN METHODS:Traditional MR is C-shaped, this thesis transform magnet to U-shaped, so that the HIFU treatment head can be placed above the opening on the MR. This idea is the first in the world. At the same time, this thesis do a lot of research in the magnetic compatibility, fast magnetic resonance imaging, magnetic resonance temperature measurement, phased array transducers, HIFU treatment plan by the latest technology and a breakthrough.After the completion of the integration system, this thesis verifies the system performance in type test, and validates function in experiments.RESULTS: By type test and related experiments to validate that the integration system can provide the following features:diagnostic by MR, positioning by MR, therapy by HIFU, monitoring by MR, thermometry or imaging for efficacy assessment by MR; and the performance of the system has completed the intended requirements, the design is accord with clinical applications.CONCLUSIONS:In the low field home-built permanent MR guided, the integration system can achieve all the functions, the positioning image is much clearer than ultrasound scanner, and the price of low field MR is much cheaper than high field MR, means that the integration system reduces the cost of products greatly and improves the practicability. But there is a certain gap of the image quality needs to be further improved in the integration system compare with high field superconducting MR.