The Realization And Application Of MR Thermometry In The Focused Ultrasound Surgery System

Focused ultrasound surgery is a promising noninvasive thermotherapy.With the help of MRI,the safety of the surgery has made a great progress as well as the postoperative evaluation.During the surgery,the MR thermometry technique helps to ensure adequate thermal dose for ablation and protects non-target areas from overheating at the same time.MRI should be integrated into our lab’s FUS system.Two projects are introduced in this dissertation.One is a matlab-based software for MR thermometry,the second is a focal positioning method used in the FUS surgery.The software obtains image files from the MR device to calculate the temperature distribution,based on which various types of data can show on the user interface.Experiments prove the software is practical and effective.For the focal positioning,at least 4 3D-coordinate points are selected in the ultrasound system coordinates.They are then sonicated with low energy that won’t make any damage.The temperature rise can be observed in the MR temperature maps,so the MR coordinates of these points can be obtained.Then,a mapping relationship between the two coordinates is established to help the focal positioning.By experimental verification,this method can make the positioning error less than 1 mm,which guarantees the accomplishment of the treatment plan.