3D Surface Reconstruction and Registration for Image Guided Medialization Laryngoplasty

The purpose of our project is to develop an image guided system for the medialization laryngoplasty. One of the fundamental challenges in our system is to accurately register the preoperative 3D CT data to the intraoperative 3D surfaces of the patient. In this paper, we will present a combined surface and fiducial based registration method to register the preoperative 3D CT data to the intraoperative surface of larynx. To accurately model the exposed surface area, an active illumination based stereo vision technique is used for the surface reconstruction. To register the point clouds from the intraoperative stage to the preoperative 3D GT data, a shape priori based ICPmethod is proposed to quickly register the two surfaces. The proposed approach is capable of tracking the fiducial markers and reconstructing the surface of larynx with no damage to the anatomical structure. Although, the proposed method is specifically designed for the image guided laryngoplasty, it can be applied to other image guided surgical areas. We used off-the-shelf digital cameras, LCD projector and rapid 3D prototyper to develop our experimental system. The final RMS error in the registration is less than 1mm. © Springer-Verlag Berlin Heidelberg 2006

Geometrical transformation approximation for 2D/3D intensity-based registration of portal images and CT scan

Conformal radiotherapy treatments need accurate patient positioning in order to spare normal tissues. Patient pose can be evaluated by registering portal images (PI) with Digitally Reconstructed Radiographs (DRR). Several methods involve segmentation which is known to be a dicult task for noisy PI. In this paper, we study another approach by using a fully 3D intensity-based registration method, without segmentation. Our approach uses the correlation ratio as similarity measure and replace DRR generation with a treatment on pre-computed DRR. A specic geometrical transformation is applied to approximate a given projection by the composition of out-of-plane rotations and inplane transformation. Some preliminary experiments on both simulated and real portal images, lead to good results (RMS error lower than 2 mm). 1 Medical contex