CHARACTERIZATION OF SAMPLING SCHEMES FOR WHOLE-BODY PET IMAGING

Whole body PET images suffer from relatively high noise levels due to inherently poor counting statistics in the emission data. Optimization of acquisition parameters is essential, to minimize any additional no ise contamination. It has previously been shown that by using a contin uous or redundant axial sampling scheme, a reduction in statistical no ise and improvement in image quality are possible. In this work, the c ontinuous axial sampling technique is further characterized and compar ed to the conventional step-and-shoot technique. The main source of ad ditional noise contamination with conventional sampling is the detecto r sensitivity normalization procedure which is applied to the emission data. With continuous axial sampling and a single normalization matri x for all planes, the statistical noise in the normalized factors is r educed by factor close to the number of planes in the scanner. The con tinuous sampling technique is shown to be less sensitive to small pati ent movements (<5 mm) compared to conventional sampling. Previously re ported problems of data handling have been resolved by rewriting the a cquisition firmware to allow on-line addition of the redundant sampled data in hardware.