Comparison of FBP and OSEM for volume determination in SPECT imaging

Region growing is often used in clinical practice for volume determination in SPECT imaging. The main problem concerning this technique is its reproducibility. Most of the parameters, like reconstruction method, filter characteristics, and threshold are tuned after trial and error by an experienced physician. The purpose of the research discussed in this paper is to obtain a fully automated, reproducible method for volume determination, based on the region growing technique. A profound comparison of reconstruction methods and filter characteristics was therefore necessary. Validation was done by phantom studies, dealing with volumes from 12 to 219 ml. The main conclusion is that the FBP image reconstruction method results in the smallest relative errors provided that it is used with a low-pass prefilter, and that region growing based on FBP images is more robust than region growing based on OSEM images.