Fan-beam And Cone-beam CT Image Reconstruction Based On The Field Theory

Computer tomography(CT)is a common method in the diagnosis of modern clinical medical imaging.According to that different tissues and organs of the human body have different penetrating for X-rays,people use sensitive instruments to measure X-rays those through the body,thereby we can reconstruct the internal cross-section or three-dimensional image of the body,so that doctors can diagnose the disease.CT has high resolution and short scan period,it is widely used in the detection of bone,organs,brain,lungs and other parts.The image scanning way is the basis of CT,and the pros and cons of scanning way directly affect the quality of CT reconstruction image.The first image scanning way of CT is parallel beam,but because of the too long scanning time and the limit of machinery cost and precision,it's difficult to get a set of parallel X-ray.It's only commonly used in the first generation of CT.Fan beam scanning is a single X-ray source and multi-detector,it can collect multiple projections at a time.From the second generation until the fifth generation of CT machines are used fan beam scanning.Cone beam scanning is the inheritance and development of two-dimensional fan beam scanning.It can simultaneously scan multiple layers of tissue,and there are a lot of advantages,such as low cost,high speed,higher spatial resolution,shorter data acquisition time,higher radiation efficiency,according with the actual production,save costs.So it's widely used in CT.Through the study of Natterer's reconstruction theory,we find that the problem of image reconstruction can be regarded as the inverse problem of field source.The application of field theory can help us to understand the problem of image reconstruction from another angle.Based on field-based parallel beam image reconstruction,the research of fan beam,three-dimensional parallel beam and cone beam CT image reconstruction based on field theory has been carried out in this paper,and extended to the accurate three-dimensional reconstruction based on field theory.In order to verify the feasibility of this method,we use the model to carry out experiment.The experimental results show that the reconstructed image is consistent with the model.