Research On Super-resolution Cone-beam SPECT Imaging System

In single-photon emission computed tomography(SPECT),the radioactive tracer injected into the human body radiates gamma photons and is received by the detector after passing through the human body.To determine the direction of gamma radiation,collimators need to be added to the detector.In order to achieve effective sensitivity,the collimator aperture can’t be reduced to zero.This non-zero collimator aperture causes the decreased resolution of reconstructed images.That is,collimator blurring.This effect resulted in reduced reconstructed image quality.For the correction of the blur of parallel-beam collimators,Lewitt proposed a method for the correction,which applied in the frequency domain.In clinical applications,fan-beam and cone-beam collimators have become the first choice for brain and chest imaging due to the improvement of photon counting density and spatial resolution.So they can improve the imaging of small objects.It is common practice to correct fan-beam and cone-beam collimator blur by rebin fan-beam or cone-beam projections into parallel-beam projections and then using Lewitt’ method for correction.In this paper,we proposed a new method for the fan-beam and cone-beam projection collimator blur correction.In the proposed method,we can obtain the two dimension Fourier transform of parallel-beam projection directly from the fan-beam or cone-beam projection data without the need of rebin.Super-resolution reconstruction is an effective way to improve image resolution on existing devices.In order to further improve the spatial resolution of SPECT imaging,we propose two new gamma photon acquisition methods for cone-beam SPECT.Combined with the super-resolution reconstruction,we proposed the super-resolution reconstruction algorithm for cone-beam SPECT.In short,we focus on the improvement of SPECT spatial resolution in this paper.We proposed a method to correct the blur effect of fan-beam and cone-beam collimator.Besides,we applyed super-resolution reconstruction to cone-beam SPECT projection,and proposed a super-resolution reconstruction method for cone beam SPECT.The experimental simulation results verify the correctness and validity of the above algorithm,and laid the theoretical foundation for the application of cone projection SPECT.