sentences:  Image fusion has become a common term used within medical diagnostics and treatment.The term is used when multiple images of a patient are registered and overlaid or merged to provide additional information.Fused images may be created from multiple images from the same imaging modality, or by combining information from multiple modalities, such as magnetic resonance image (MRI), computed tomography (CT), positron emission tomography (PET), and single photon emission computed tomography (SPECT).