Characteristics of the PET Component of a Dedicated Breast PET/CT Scanner Prototype

A dedicated breast PET/CT system is being constructed at our institution. In this work, we characterize aspects of the performance of the PET component, and investigate the accuracy of image registration for the PET and CT systems. Energy resolution was determined on a per-crystal basis from a segmented flood image. Reconstructed spatial resolution was determined using a phantom consisting of four point sources at a range of positions. A miniature Derenzo phantom was also imaged for visual inspection of resolution. Data were reconstructed with both FBP and MAP. A registration phantom with fiducial makers was constructed to test image registration accuracy. The overall average energy resolution achieved was 25%. The spatial resolution achieved by FBP reconstruction was 3.8 mm. In the Derenzo phantom experiment, 4.8, 4.0 and 3.2 mm rods were clearly resolved by FBP, and 4.8, 4.0, 3.2 and 2.4 mm were clearly resolved by MAP. The accuracy of registration was measured as 0.30 mm. The results show that PET component of our PET/CT system is yielding reasonable tomographic images, particularly when MAP reconstruction is used. Image registration between the PET and CT systems is effective.