Performance characterisation of large area BaF2-TMAE detectors for use in a whole body clinical PET camera

The first of two large area detectors which form part of a new whole body positron scanner has been fully characterised and a performance assessment has been completed. The detector consists of an array of crystals coupled to a large area, low pressure multiwire chamber filled with tetrakis-(dimethylamino)-ethylene (TMAE) gas. A complete optimisation has been carried out in the operation of the chamber in order to establish optimal levels of stability and performance. Under the optimised operational conditions the detector exhibits an efficiency of ∼ 25%, with a time and position resolution of 3.5 ns (FWHM) and 6.5 mm (FWHM) respectively. A Monte Carlo simulation of the complete dual headed PET camera has been used to assess the expected image quality in terms of contrast and signal to noise ratio. The simulation has been also used to establish the effect of utilising crystal slabs and a support frame to cover the active area of each detector in comparison with a single sheet of BaF2. The results demonstrate that the use of crystal tiles results in a small increase in the background noise, not significantly compromising the image quality.