Neuroimaging Facilities

Neuroimaging Facilities

I want to start a MRI study MRI Time Request	MRI Scanner The scanner, a 3.0 Tesla GE SIGNA MRI, was installed in Oct. 2000, and recently upgraded to the EXCITE hardware platform in April 2005. The system has advanced imaging gradients with a maximum amplitude of 40 mT/m and a slew rate of 150 mT/m/msec and 8 fast (500 kHz) receiver channels (an upgrade to 16 channels has been scheduled for late 2005). The ability to develop custom pulse sequences for the scanner is provided by GE using a software development package - EPIC. Brain imaging studies (fMRI, structural and DTI) are done using either a quadrature birdcage coil or an 8-channel array head coil supplied by GE. Parallel imaging may be performed using the 8-channel array coil and GE's ASSET software option. Visual stimulation can be delivered by using an advanced fiber optic goggle system (Avotec), the high resolution Visuastim XGA system (Resonance Technology), or using back-projection with an LCD projector and a screen at the end of the table. The Avotec fiber optic goggles are interfaced with SensoMotoric Instruments eye-tracking system (sampling rate of 50 HZ). This eye-tracking system yields four different analyses: percentage analysis, pictorial analysis, order of object vs. time, and pupil diameter vs. time. Auditory stimulus is presented using a pneumatic headphone system (Avotec). All auditory stimuli are presented through a digital equalizer that is optimized for tone and clarity. Stabilizing patients to minimize head movement is critical for MRI studies. The lab has three head stabilizing methods: bite bars, vacuum pillow, and foam inserts. Collection of electrodermal activity during MRI scanning is achieved using a Coulbourn Instruments skin conductance coupler with 8 mm Ag-AgCl electrodes placed on the tips of the index and third finger. The electrodes are filled with a NaCl paste (49.295 grams of unibase and 50.705 grams of isot. NaCl 0.9%). The electrode leads are shielded and the signal low pass filtered to reduce RF interference from the scanner. The skin conductance signal is then digitized and sampled at 20 Hz using a National Instruments DAQPad 6020E. Digital event markers are simultaneously output from the stimulus presentation PC to the DAQPad, to enable precise time alignment of skin conductance responses with stimuli onsets/offsets. The MRI facilities are supported by a full-time physicist, imaging technologists, and research staff.
PET Time Request	PET Scanner The laboratory houses a complete PET research facility, complementing the previously established PET research labs under the Medical Physics department. The lab houses a GE Advance PET scanner along with its adjacent control room, subject prep room, and blood metabolite analysis lab. These imaging resources are optimized for research applications, with ample space for research teams and equipment, multiple redundancy in data and power lines to support modified equipment needs, special modifications for bedside dose preparation and delivery, and easily accessible hardware mounting and cable access for ceiling, floor, and wall mounted equipment such as activation stimulus presentation and subject telemetry. The Advance scanner consists of 336 detector units of dimensions of 50 mm axial by 24 mm transaxial by 30 mm radial. The units are arranged to form 18 rings with 672 crystals each, giving 35 contiguous 2-D image planes through an axial field of view (FOV) of 15.2 cm. The rings are separated by 1 mm thick, 12 cm deep retractable tungsten septa. The maximum transaxial FOV is 55 cm in diameter through a 59 diameter patient port.The transaxial resolution of this scanner is 5.5 mm FWHM, and axial resolution is 4.7 mm FWHM in 2D mode and 6.2 mm in 3D mode.
Micro PET Time Request	MicroPET Scanner The Concord Microsystems microPET-P4 is the only commercial animal PET scanner available using LSO crystals. The microPET model P4 has a large enough field of view (FOV) to allow for single position acquisition of an entire rhesus brain or whole body rat or mouse. The scanner has four rings of 42 detectors at a 26 cm diameter. Each detector consists of an 8 x 8 array of 2 mm x 2 mm x 10 mm LSO crystals, for a sum total of 10752 LSO elements. Data is acquired in 3D mode (no septa), allowing for maximum sensitivity with nearly 58 million 180° coincident lines of response. External lead shielding minimizes interference from radioactive sources outside the FOV, reducing the animal port to 22 cm. Data is recorded in list mode, permitting maximum post analysis flexibility in time averaging and potential real time histogramming. The expected absolute sensitivity of 250 keV is 500 cps/mCi. Several data reconstruction algorithms are available, including filtered back projection (FBP) and ordered subset expectation maximization (OSEM) modified for 3D data sets. The calculated image resolution with FBP in the central FOV is 2 x 2 x 2 mm, or a factor of 16-22 improvement in the volume resolution over our current human PET scanners (CTI ECAT 933 and GE ADVANCE). The new microPET was delivered in September 2002.
	Tandem Accelerator High yield radioisotope production is carried out with a National Electrostatics Corporation 9SDH-2 electrostatic tandem accelerator capable of accelerating >100uA of protons or deuterons to 7 MeV with fine beam shaping and positioning capabilities, with high yield targetry systems for ¹¹C, ¹³N, ¹⁴O, ¹⁸F, and newly developed PET radioisotopes such as ¹⁷F. A research chemistry lab with dual fume hoods and a class 10,000 clean room with class 100 laminar flow hood are available for radiotracer production and radiopharmaceutical preparation. The lab is well equipped for in-line production and delivery of short lived tracers. The facility includes separate animal handling and transport accommodations, including air handling considerations for unimpeded basic research. Other support resources include a fully equipped machine shop, developmental and diagnostic electronics apparatus, a clean stainless steel transfer line network for specialty gases and liquids, including radioactive and corrosive materials, and ample bench space for cutting edge instrumentation development and repair.
	EEG The laboratory houses a 256-channel EEG/ERP recording with the Electric Geodesics Inc. (EGI) system. Our system uses Geodesic Sensor Net 200 (256-channel), Net Amps 200 (high-input impedance (200 MOhm) dense-array amplifiers), and Net Station 2.0. MRI-compatible 256-channel Geodesic Sensor Nets with Ag/AgCl-coated, carbon-filled plastic electrodes can be used for simultaneous fMRI and EEG recording.
	Scanning Simulator To acclimate patients to the unique environment of the MRI scanner, the lab houses a simulator room. This room has a mock MRI scanner, another Avotec fiber optic goggle system, and auditory system with two control computers. A motion detection system (based upon linear accelerometers) with video feedback is available for training subjects to not move in the scanner. This room is used to introduce subjects to the identical experimental procedures that they will experience in the actual scanner. This is done to ensure subject comfort and data quality.