Physical performance of a prototype 3D PET scanner using CdTe detectors

We developed a prototype 3D PET scanner that uses CdTe semiconductor detectors. The scanner is dedicated to human brain imaging. A semiconductor detector should have advantages when used as a PET detector (e.g. good quantitative imaging and high-spatial resolution). The detectors incorporate three important technical features: stacked crystals, no contact with the board, and direct soldering onto the board. Our scanner comprises 18 detector units with a 350-mm-diameter patient port that has a transaxial field of view of 310 mm and an axial field of view of 250 mm. We demonstrated the scanner had a timing resolution of 6.8 ns (FWHM), an energy resolution of 4.1% (FWHM), and a spatial resolution such that hot rods down to 2.5 mm in diameter were visually separated. These results showed that our scanner should produce quantitative imaging with a high-spatial resolution.