Study of relative quantification of Tc-99m with partial volume effect and spillover correction for SPECT oncology imaging

The apparent concentration of activity in nuclear medicine images is altered by the finite spatial resolution of the imaging systems blurring the counts emitted at a given site out into a surrounding volume in the reconstructed slices. If a structure only partially occupies this volume then more counts will be lost from the location then are brought back in to it from activity within the structure. This is the partial volume effect (PVE). Similarly, counts from surrounding structures can be blurred into the structure. This spillover (SO) also alters the apparent concentration of activity. In total these effects alter the detection and quantification of activity within structures. The increased availability of dual-modality imaging systems whereby high-resolution anatomical information which is registered with the emission slices makes this anatomical information available for use in correcting for the PVE and SO. In this study we investigated the use a template projection-reconstruction method for correction PVE and SO in terms of both its impact of visual image quality and the quantification of activity in simulated spheres of varying contrast relative to a uniform background distribution of activity. We determined that such corrections can dramatically improve both the visualization and quantification of activity within the spheres