A new 3-D double window adaptive Hybrid Smoothing Algorithm and its applications to radionuclide images

In contrast with most static studies in nuclear medicine, dynamic studies h ave an inherently high noise level because of low count statistics. Preproc essing of the raw image data by the application of suitably designed smooth ing filters, provides a significant contribution to the dynamic studies. Be cause dynamic studies are 3-D, consisting of two spatial dimensions and tim e, preprocessing of the raw image data by a specially tailored 3-D filter, would be expected to fit more precisely and efficiently than the utilizatio n of conventional 2-D filters. In this study, a new 3-D Double Window Adapt ive Hybrid Smoothing Algorithm (3-D DWAH filter) is introduced and the resu lts obtained by its application on the pixel basis dynamic renal scintigrap hic images are compared with those of the conventional filters and unsmooth ed raw data. The 3-D DWAH filter effectively and optimally combines the FIR -Median Hybrid (FMH) and the running mean filters within a variably tuned i nterval providing a significant improvement in SNR without unacceptable deg radation of spatial and temporal resolution.