THE IMPORTANCE AND IMPLEMENTATION OF ACCURATE 3D COMPENSATION METHODSFOR QUANTITATIVE SPECT

The purpose of this study was to investigate the importance of 2D vers us 3D compensation methods in SPECT. The compensation methods included in the study addressed two important degrading factors, namely attenu ating and collimator-detector response in SPECT. They can be divided i nto two general categories. The conventional methods are based on the filtered backprojection algorithm, the Chang algorithm for attenuation compensation and the Metz filter for detector response compensation. These methods, which were computationally efficient, could only achiev e approximate compensation due to the assumptions made. The quantitati ve compensation methods provide accurate compensation by modelling the degrading effects at the expense of large computational requirements. Both types of compensation methods were implemented in 2D and 3D reco nstructions. The 2D and 3D reconstruction compensation methods were ev aluated using data from simulation of brain and heart, and patient tha llium SPECT studies. Our results demonstrate the importance of compens ation methods in improving the quality and quantitative accuracy of SP ECT images and the relative effectiveness of the different 2D and 3D r econstruction/compensation methods. We concluded that 3D, implementati on of the quantitative compensation methods provides the best SPECT im age in terms of quantitative accuracy, spatial resolution, and noise a t a cost of high computational requirements.