ITERATIVE RECONSTRUCTION OF F-18 SPECT USING GEOMETRIC POINT RESPONSECORRECTION

This article demonstrates resolution recovery in F-18 SPECT image reco nstruction by using an iterative algorithm that corrects for the syste m geometric response. Methods: Patient and phantom studies were perfor med using a Picker PRISM 3000 three-detector SPECT system (Picker Inte rnational, Inc., Cleveland, OH) to image F-18 With 511 keV collimators . A measured point response function of the imaging system was used in an iterative reconstruction algorithm in which the projector and back projector modeled the system point response function by using an effic ient layer-by-layer blurring technique. The blurring function was a fi ve-element kernel in the shape of a cross. The iterative reconstructio n algorithm was an ordered-subset maximum-likelihood expectation maxim ization algorithm. Results: The iterative reconstruction algorithm wit h geometric response correction showed an improvement in resolution ov er the filtered backprojection reconstruction and the iterative recons truction without correction. Conclusion: The proposed iterative recons truction algorithm with geometric response correction is efficient and effective with significant resolution recovery.