Three approaches to dynamic SPECT imaging

The role of dynamic imaging is to track rapid changes in the temporal and spatial distribution of the tracer. For rotating camera SPECT, however, the projections required for a single image are collected sequentially, so each projection represents a different radiotracer distribution and special methods need to be used in order to determine kinetic parameters. In this paper the authors present preliminary results of their research towards a comparison of three different approaches to dynamic SPECT imaging: (a) the image based (IB), (b) the weighted interpolation (WI), and (c) the direct parameter (DP) reconstruction methods. The authors have performed simulation studies as well as experiments using their dynamic phantom. The data for multiple regions with characteristic times corresponding to 2-8 min have been acquired using different SPECT protocols. These data were analyzed for each method in terms of spatial resolution and the accuracy of reconstruction of the characteristic times as compared with the preset values. The hardware requirements for each method and the complexity of the acquisition protocols and data processing were compared. The acquisition protocol for DP SPECT is much simpler than that for the other two methods, since it does not require multiple detectors nor multiple camera rotations, but ease of data processing for the IB method may outweigh this advantage with the WI method placed in the middle. However, with software optimization, the DP should become a method of choice for clinical studies.