Design of a high-resolution, high-sensitivity PET camera for human brains and small animals

The authors present design parameters for a 3-D PET camera with high sensitivity (35 cm detector ring diameter, 15 cm axial field of view) and isotropic high resolution provided by detector modules capable of depth of interaction (DOI) measurement. Detector modules are made of LSO crystals (3 mm square by 30 mm deep)-the small module size and short decay time of LSO reduce the detector dead time by a factor of 14 compared to conventional EGO detector modules and narrow the coincidence window width to 4 ns. This yields an expected peak noise equivalent count rate of 800 kcps and noise equivalent sensitivity of 1370 kcps/μCi/cc with a 20 cm diameter phantom-three to five times higher than conventional scanners. With 5 mm fwhm DOI resolution, the expected reconstructed spatial resolution is <3.0 mm fwhm throughout the entire field of view. Depth of interaction measurement information is incorporated into the reconstruction algorithm by rebinning onto a regularly spaced grid. Attenuation correction is performed with an orbiting single transmission source