mutual information (mi) is a widely used similarity metric for multimodality image registration. however, it involves an extremely high computational time especially when it is applied to volume images. moreover, its robustness is affected by existence of local maxima. the multi-resolution pyramid approaches have been proposed to speed up the registration process and increase the accuracy of th...

background: medical image interpolation is recently introduced as a helpful tool to obtain further information via initial available images taken by tomography systems. this information may be useful for better diagnosis of possible lesions or better tumor delineation at radiation treatment. to do this, deformable image registration algorithms are mainly utilized to perform image interpolation ...

medical image registration methods which use mutual information as similarity measure have been improved in recent decades. mutual information is a basic concept of information theory which indicates the dependency of two random variables (or two images). in order to evaluate the mutual information of two images their joint probability distribution is required. several interpolation methods, su...

Image registration is a crucial step in most image processing tasks for which the final result is achieved from a combination of various resources. In general, the majority of registration methods consist of the following four steps: feature extraction, feature matching, transform modeling, and finally image resampling. As the accuracy of a registration process is highly dependent to the fe...

Background: One of the challenges of PET/MRI combined systems is to derive an attenuation map to correct the PET image. For that, the pseudo-CT image could be used to correct the attenuation. Until now, most existing scientific researches construct this pseudo-CT image using the registration techniques. However, these techniques suffer from the local minima of the non-rigid deformation energy f...

Background: Medical image interpolation is recently introduced as a helpful tool to obtain further information via initial available images taken by tomography systems. To do this, deformable image registration algorithms are mainly utilized to perform image interpolation using tomography images.Materials and Methods: In this work, 4DCT thoracic images of five real patients provided by DI...

Mutual information (MI) is a widely used similarity metric for multimodality image registration. However, it involves an extremely high computational time especially when it is applied to volume images. Moreover, its robustness is affected by existence of local maxima. The multi-resolution pyramid approaches have been proposed to speed up the registration process and increase the accuracy of th...

background: to reduce uncertainties of patient positioning, the computerized tomography (ct) images acquired at the treatment planning time can be compared with those images obtained during radiation dose delivery. this can be followed during dose delivery procedure as image guided radiotherapy (igrt) to verify the prescribed radiation dose delivery to the target as well as to monitor radiation...