An apparatus for optical imaging of Cerenkov luminescence from a region of interest on a subject subsequent to the subject receiving a dose of a radiopharmaceutical, the apparatus comprising: an imaging means capable of imaging Cerenkov photons； a fibrescope for transmitting light received at a distal end of the fibrescope to a proximal end of the fibrescope, the proximal end of the fibrescope being connected to the imaging means； and an optical shroud for surrounding the distal end of the fibrescope and for covering a region of interest.
