Determination of tracer arrival delay with spectral analysis

This work presents the application of the nonnegative leasts squares (NNLS) algorithm, which is commonly used in the spectral analysis of positron emission tomography (PET) data, to a general and fast method of detecting the tracer arrival delay in brain PET studies. It takes into account a vascular contribution to the tissue response function and does not involve multiple iterations. No assumptions on the model order of the tissue response function are required. It is based on the whole scanner count rate of true coincidences every second in the field-of-view and the whole blood activity concentration from the on-line blood detector system. The presented method has been used for the analysis of neuroreceptor ligand studies. An example with the serotonin 5-HT_2A receptor ligand [¹¹C]MDL100,907 is included