DESIGN OF A VARIABLE FIELD PROTOTYPE PET CAMERA

A prototype PET camera has been designed and is being constructed to t est the concept, and develop the engineering design and production met hodology for a variable field PET camera. The long term goal of the de sign is to develop a lower cost, high resolution PET camera. The camer a has eight detector heads which form a closely packed octagon detecto r ring with an average diameter of 44cm for brain/breast and animal mo del imaging. The heads can be translated radially to a maximum ring di ameter of 70cm for whole body imaging. In the larger diameter modes, t he camera rotates 45 degrees during imaging. The camera heads can be s et to intermediate positions to fit the camera to the subject size to, maximize detection sensitivity and sampling uniformity. Special desig n features for imaging the breast and the axillary metastases have bee n incorporated. The detector design implemented is the quadrant sharin g photomultiplier (PMT) design using circular 19mm PMT. The EGO detect or pitch size is 2.7x2.7mm. The prototype camera images 27 slices simu ltaneously with an axial field of view (FOV) of 39mm. The prototype's limited axial FOV, which is appropriate for testing the camera concept , would be expanded in a next-generation clinical camera implementatio n. Preliminary simulation studies have been performed to evaluate the resolution, sensitivity, and sampling uniformity.