pet vs. spect: in the context of ongoing developments

this paper intends to compare the abilities of the two major imaging modalities in nuclear medicine imaging: positron emission tomography (pet) and single photon emission computed tomography (spect). the motivations are many-fold: (i) to gain a better understanding of the strengths and limitations of the two imaging modalities in the context of recent and ongoing developments in hardware and software design; (ii) to emphasize that certain issues, historically and commonly thought as limitations, may now be instead viewed as challenges that can be addressed; (iii) to point out that existing pet and spect scanners in the field can (much) benefit from improvements in image-reconstruction software; (iii) to point-out (to engineers, physicists and software-developers) important areas of research in pet and spect imaging that will be instrumental to further improvements in the two modalities;