Design and performance of a rotating positron tomograph, RPT-2

• Main Authors: Townsend, David W, Byars, Larry G, Defrise, Michel, Geissbuhler, Antoine, Maguire, RPaul, Missimer, Jack, Roddy, Raymond, Brun, Tony, Mintun, Mark A, Nutt, Ronald
• Format: Conference Proceeding
• Language: English

A new rotating positron tomograph, RPT-2, has been designed and built, following the successful operation of an earlier prototype (RPT-1). The new tomograph comprises two arrays of 80 x 24 BGO detectors using the 54 mm x 54 mm x 20 mm block from the commercial ECAT EXACT scanner. As with the earlier prototype, the arrays are rotated to acquire the full projection data set. The tomograph has no septa, and acquisition and reconstruction are fully three dimensional. Forty-seven planes are imaged over an axial length of 15.6 cm. Transmission scans are performed by positioning a solid super(68)Ge arc source in front of one array of detectors. The tomograph has a scatter-subtracted sensitivity of 225 kcps/ mu Ci/ml, a factor of 3.5 less than the full-ring EXACT operated with septa retracted (3D), but 25% greater than the EXACT with septa extended. The maximum NEC is 24 kcps, compared with 38 kcps for the EXACT in 3D. Spatial resolution and scatter fraction are comparable to the EXACT. The new tomograph has been used for a range of clinical and research applications with super(18)FDG, placing particular emphasis on oncology and whole body studies. RPT-2 offers a cost-effective solution for clinical PET scanning.