The incorporation of organ uptake into dynamic SPECT (dSPECT) image reconstruction

Dynamic SPECT (dSPECT) is an image reconstruction method capable of determining three dimensional regional estimates of physiological kinetic rates while still maintaining the simple acquisition protocol of a single, slow camera rotation. Through the use of inequality constraints in a least squares optimization routine, the authors are able to determine both the rate of tracer uptake and subsequent tracer washout over the acquisition time of the SPECT scan. Simulations modelling different camera acquisition geometries and with variable dual exponential kinetic parameters and model complexity (e.g., statistical noise, object attenuation) were performed. It was found that kinetic parameters were accurate to within 50% of the true values for the case of fast uptake and slow washout for a single head acquisition and improved to within 95% when acquired with a triple head camera. Experimental phantom tests corroborated these results and are shown to have an accuracy of about 90%. A preliminary patient study of renal dynamics has also been performed and compared with conventional planar dynamic imaging. Results from this study indicate that the dSPECT reconstruction method is able to determine kinetic information with accuracy comparable to that of conventional planar dynamic imaging methods while providing additional three dimensional time behaviour information.