ABSTRACTNeuroimaging allows noninvasive evaluation of the anatomy, physiology, and function of the brain. It is widely used for diagnosis, treatment planning, and treatment evaluation of neurological disorders as well as understanding functions of the brain in health and disease. Neuroimaging modalities include X-ray computed tomography (CT), magnetic resonance imaging (MRI), single photon emis...

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 ...

Spontaneous photon emission can be drastically modified by placing quantum emitters (QEs) in nanostructured environment, resulting dramatically enhanced rates due to the Purcell effect along with generation of collimated single-photon beams propagating design directions and featuring well-defined polarization states. Recent advances engineering demonstrate fascinating possibilities for directio...

-The relevance of gauge invariance in considering the question of emission of photons in the presence of external electromagnetic field from the ground state of quantum mechanical systems is studied. With an exact numerical calculation for atomic hydrogen, it is shown that the photons cannot be unequivocally assigned to have been emitted from the ground state due to the invariance of gauge of t...