Transesophageal high-intensity focused ultrasound(HIFU) energy can be used to treat cardiac arrhythmiaefficiently non-invasively. Since the esophagus is locatedjust behind the heart, it offers a perfect acoustic window.Hence, HIFU can be directed toward the heart to performablation. In a previous study a HIFU probe with one 2DUS image perpendicular to the esophagus axis for guid-ance purpose has been proposed. A new dual-mode HIFUprobe with two perpendicular 2D US imaging plane is nowunder development. In this paper we propose a therapyguidance system, based on an intensity-based registrationof the two perpendicular 2D US to preoperative 3D CT.As a proof of concept we developed the following evalua-tion framework on a numerical phantom: 1) because theprobe is under development we define a ground truth (GT)initial pose inside a CT volume and simulated two perpen-dicular US images from the CT data; 2) we run the regis-tration framework from 55 randomly defined pose initial-izations around the initial GT pose; and 3) we estimatedthe accuracy of the registration by (a) the transformation parameter estimation errors (translation error and quater-nion distance for rotation) and (b) Target Registration Error (TRE) on 8 features. The accuracy of the registration using two 2D US plane has been compared to the previous work performed on only one US plane. An improvement was observed when using two 2D US planes with regards to the previous one US plane