Methods to improve the precision of positioning in the MR-guided focused ultrasound surgery system

MR-guided pHIFU (phased High Intensity Focused Ultrasound) system can realize non-invasive ablation of tumors. In order to use MR as the guidance, there must be a precise transfer matrix between the MR and HIFU system. In this paper, some methods are proposed to improve the precision of positioning. One image-processing algorithm is used to automatically pick up the points. Furthermore, this paper proposes a new temperature positioning method based on multiple foci heating mode, and use optimal selection algorithmto reduce errors. In terms of results, using the automatic algorithm only took about 10 seconds to get all the points coordinates. It was shorter than the artificial method, which took at least one minute. It also proved that the optimal selection algorithmcould reduce errors. The standard deviationusing artificial method was 6.5899, and the standard deviationof automatic method reduced to 1.8445.