Performance characteristics of the novel PETRRA positron camera

The PETRRA positron camera consists of two 60 cm×40 cm annihilation photon detectors mounted on a rotating gantry. Each detector contains large BaF2 scintillators interfaced to large area multiwire proportional chambers filled with a photo-sensitive vapour (tetrakis-(dimethylamino)-ethylene). The spatial resolution of the camera has been measured as 6.5±1.0 mm FWHM throughout the sensitive field-of-view (FoV), the timing resolution is between 7 and 10 ns FWHM and the detection efficiency for annihilation photons is ∼30% per detector. The count-rates obtained, from a 20 cm diameter by 11 cm long water filled phantom containing 90 MBq of 18F, were ∼1.25×106 singles and ∼1.1×105 cps raw coincidences, limited only by the read-out system dead-time of ∼4 μs. The count-rate performance, sensitivity and large FoV make the camera ideal for whole-body imaging in oncology.