PET image reconstruction based on several respiratory-phase low-dose CT images

Positron emission tomography (PET) can provide functional information in the human body. However, thoracic and abdominal PET images suffer from attenuation-related errors due to respiratory motion as well as blurs due to respiratory motion itself. In our previous study, to obtain respiratory-gated PET images, we proposed a novel method for respiratory phase matched attenuation correction (AC) and motion compensation (MC). That method utilizes a virtual 4D CT image generated via non-rigid registrations among a 3D CT image and a couple of respiratory-phase 3D MR images. In this paper, for respiratory phase matched attenuation correction and motion compensation, we propose to use a couple of respiratory-phase low-dose CT images rather than MR images. Experimental result for a clinical dataset shows that the proposed method can also provide much clearer organ boundaries as well as more accurate lesion information than the conventional method in a 3D PET image.