Facilities and Instrumentation
The University of Pittsburgh's PET Research Facility is housed in approximately 12,000 sq. feet of dedicated research space on the 9th floor of Presbyterian University Hospital's B-wing. Included in this space are a 3000 sq. ft. Radiochemistry Laboratory, three 500 sq. ft. scanner bays, two control rooms, and offices for PET Facility faculty and staff.
The PET Radiochemistry Laboratory produces radionuclides and investigational radiopharmaceuticals for PET imaging using a dedicated Siemens Eclipse HP medical cyclotron. The Eclipse HP is an 11 MeV negative-ion cyclotron equipped with targetry for producing the positron-emitting radionuclides carbon-11, fluorine-18, nitrogen-13, and oxygen-15. Supported Radiosynthetic apparatus includes a G.E. Healthcare TRACERLab™ FX MeI gas-phase [C-11]methyl-iodide system, two TRACERLab™ FX M carbon-11 incorporation platforms, and a FASTlab™ fluorine-18 incorporation platform, which provides the desired short duty cycles and repeat production capabilities needed to maximize the production capabilities of the cyclotron and achieve the high specific activity radiopharmaceutical productions required for human and preclinical neuroreceptor imaging studies. Modules for [O-15]-labeled gases (oxygen, carbon monoxide, and carbon dioxide) are in use. A Victoreen gas delivery system provides [O-15]-labeled gases via a remotely operated inhalation system connected to the PET scanning rooms. High specific activity [C-11]-labeled carbon dioxide and carbon monoxide gases are also available. The radiochemistry laboratory is equipped with three full-size Capintec-brand hot cells fitted with three pairs of remote manipulators for operator-assisted radiopharmaceutical productions. In addition, there are two large stacked Capintec mini-cells and four smaller Capintec mini-caves for routine automated productions, three radioisotope fume hoods, five organic synthesis fume hoods, two laminar flow hoods, twelve radio-HPLC systems (including gradient pumps, variable wavelength UV detectors, two photodiode array detectors, a refractive index detector, an electrochemical detector, and about 20 radioactivity detectors), and miscellaneous analytical equipment including a radio-TLC scanner, radio-GC, Varian Saturn GC-MS, two gamma well counters (Packard Cobra model 5003), a Fuji BAS-5000 phosphor imager, and FTIR, and UV/vis spectrometers. Imaging Instrumentation
The PET Facility operates four dedicated research scanners:
Siemens Biograph mCT Flow PET/CT. Operational in March 2015, this state-of-the-art PET/CT scanner offers 21.6 cm of axial scan coverage (TrueV option) with an intrinsic in-plane spatial resolution of ~ 4.2 mm FWHM. The CT subsystem is a 64-slice helical scanner that can be used to acquire diagnostic quality CT or a low-dose scan for the purpose of attenuation correction of PET emission data. This unit is equipped with Siemens’ FlowMotion technology supporting continuous bed motion acquisition, HeartView CT and both cardiac and respiratory gating hardware for reconstructing phase-matched PET and CT images, SAFIRE iterative CT reconstruction, and SMART NeuroAC for calculated attenuation correction for brain imaging. The mCT will replace the legacy Siemens ECAT HR+ PET scanner as the primary instrument supporting human investigational research studies, and is fully equipped to support brain, cardiac, and oncology imaging studies.
Siemens Biograph mMR PET/MR. Operated jointly with the University of Pittsburgh Magnetic Resonance Research Center (MRRC), the mMR allows simultaneous acquisition of whole-body MR and PET. The mMR utilizes a 3T niobium–titanium magnet (length: 163 cm; bore: 60 cm), an actively shielded whole-body gradient coil (length: 159 cm; amplitude: 45 mT/m; slew rate: 200 T/m/s), and a radiofrequency body coil (peak power: 35 kW; transmitter bandwidth: 800 kHz). The MR system can acquire a 0.5–50 cm FOV, with a 2D slice thickness of 0.1 - 200 mm, 3D slab thickness from 5 - 500 mm, maximum matrix size of 1,024 elements, and maximum resolution of 9 mm. A PET detector assembly exists between the gradient and radiofrequency coils: 8 rings of 56 detector blocks, 8x8 LSO crystals (4x4x20 mm) per block, coupled to an array of 3x3 APDs for a total of 4,032 channels. The PET system (127 planes; transaxial FOV: 59.4 cm; axial FOV: 25.8 cm) can acquire static multibed and list-mode data in 3D mode.
Siemens ECAT HR+ PET Scanner. Operational in 1995, the HR+ scanner is now considered legacy equipment with limited vendor support. The HR+ system will continue to be supported through 2015 in order to complete data collection as part of serial imaging studies spanning several years, after which time the scanner will be retired.
A Photodiagnostic Systems, Inc. (PDSI) NeuroPET/CT scanner. Installed in 2013 as a beta prototype, the NeuroPET/CT system is a portable, state-of-the-art human brain and primate PET/CT scanner, being the first commercially available PET system to employ silicon photomultiplier (SiPM) technology in place of photomultiplier tubes. The scanner is comprised of LYSO:(Ce) dual-layer Phoswich detectors segmented into 2.3 x 2.3 x 20 mm crystal elements. The bore is sufficiently large (34 cm) to accommodate a human head or the thorax of a large primate. A large axial field-of-view (22 cm) allows the entire human brain or primate thorax to be imaged in a single bed position and covers a large solid angle, a key contributor to the system’s high efficiency (~8%). The maximum intrinsic spatial resolution of the NeuroPET/CT is approximately 2.3 mm FWHM. The CT subsystem is a fully integrated 8 slice helical CT scanner (1.25 mm pitch) that can deliver 1-7 mA of 100-140 kVp x-rays with a maximum helical scan rate of 1 cm/sec. The CT can be used to produce diagnostic quality CT images or alternative low-dose scans for attenuation correction of PET emission data.