A framework for image-guided breast surgery

Breast-conserving surgery for the treatment of cancer frequently requires a repeat operation due to the initial excision of the tumour being incomplete. Improved image guidance, using preoperative MR images, might help to reduce this high re-excision rate. Since the diagnostic MR images are acquired prone, but surgery is performed supine, significant deformation of the soft tissue of the breast occurs. We have developed an approach to account for this deformation based on a patient-specific biomechanical model. The model is constructed from a supine MR image, and it is used to initialize a non-rigid intensity-based registration of the diagnostic prone MR image with the supine image. In the operating theatre the surface of the breast is acquired with a stereo camera, and the model is deformed to match this surface in order to predict the position of the lesion. We illustrate our framework with initial results for one patient case, in which we estimate our target registration error to be 4mm.