ABSTRACT
Automatic, or semi-automatic methods for ROI selection are available [6], however, they are not completely reliable and the activity is always counted from the full area of ROI which may still include some background organs. An alternative approach is to use some blind source separation method (BSS). They have no physiological assumption in their basic form, [11], however, some extensions have also been proposed [5, 13]. We design a mathematical model that integrates all common assumption of the domain, including convolution of the input function and tissue-specific kernels. The input function as well as the kernel parameters are considered to be unknown. They are estimated from the observed images using the Variational Bayes method [16].
