Shams, RamtinSadeghi, ParastooKennedy, RodneyHartley, Richard2015-12-100169-2607http://hdl.handle.net/1885/56763Due to processing constraints, automatic image-based registration of medical images has been largely used as a pre-operative tool. We propose a novel method named sort and count for efficient parallelization of mutual information (MI) computation designed for massively multi-processing architectures. Combined with a parallel transformation implementation and an improved optimization algorithm, our method achieves real-time (less than 1. s) rigid registration of 3D medical images using a commodity graphics processing unit (GPU). This represents a more than 50-fold improvement over a standard implementation on a CPU. Real-time registration opens new possibilities for development of improved and interactive intraoperative tools that can be used for enhanced visualization and navigation during an intervention.Keywords: 3D medical image; Graphics Processing Unit; Graphics processor unit (GPU); Graphics processor units; Image-based; Intra-operative; Medical images; Mutual informations; Novel methods; Optimization algorithms; Parallel Computation; Parallel processing; Para Graphics processor unit (GPU); Histogram; Image registration; Mutual information (MI); Parallel processing200910.1016/j.cmpb.2009.11.0042016-02-24