Spect Study Of Partial Reconstruction Algorithm

SPECT (single photon emission computed tomography) is a tomography technique that can greatly show information about the metabolic activity and improve clinical diagnosis. In 2000, R. Novikov discovered the explicit SPECT reconstruction formula with non-uniform attenuation. Like the conventional CT reconstruction algorithm, the algorithm requires full projection data in order to reconstruct the image even though reconstruction area is a small part of the body (e.g. heart). That is to say, bigger detector is needed in order to collect all projection data from the patient and more reconstruction time will be required. In clinic, doctors used to pay more attention to a local region of cross-section instead of whole section, such as a particular organ or tissue (e.g. heart). In this case, if we can find a SPECT local reconstruction method to reconstruct the local image only using the projection data from the particular organ or tissue, we just need smaller detector and reconstruction time would become shorter.Wavelet transform is one of the effective tools used widely in the field of image processing. It has excellent localization property of both time and frequency. This time and frequency analysis method could be applied to localized reconstruction and improve the resolution of the image. Besides, wavelet transform could also be applied to de-noising when reconstruction, so the time of de-noising can be cut down and reconstruction efficiency could be improved.In this paper, based on CT local reconstruction algorithm and SPECT reconstruction algorithm, we present an algorithm for local SPECT reconstruction with non-uniform attenuation by using extrapolation, which could avoid the artifacts commonly appear close to the boundary of ROI due to the truncation of projection data and reconstruct the local image only using the projection data from the particular organ or tissue. Then, the wavelet transform be applied to the algorithm for local SPECT reconstruction with non-uniform attenuation, we present a wavelet based local SPECT reconstruction algorithm. In the end, we analyze the characteristic of de-noising, and a wavelet de-noise reconstruction algorithm could be proposed.