Development of a high resolution beta camera for a direct measurement of positron distribution on brain surface

We have developed and tested a high resolution beta camera for a direct measurement of positron distribution on the brain surface of animals. The beta camera consists of a thin Ca[F.sub.2](Eu) scintillator, a tapered fiber optic plate (tapered fiber) and a position sensitive photomultiplier tube (PSPMT). The tapered fiber is the key component of the camera. We have developed two different sizes of beta cameras. One is 20mm diameter field of view camera for imaging brain surface of cats. The other is 10mm diameter camera for that of rats. Spatial resolutions of the beta camera for cats and rats were 0.8mm FWHM and 0.5mm FWHM, respectively. We demonstrated that developed beta cameras may overcome the limitation of the spatial resolution of positron emission tomography (PET).