Alexander M Grant1,2, Brian J Lee2,3, Chen-Ming Chang2,4, Craig S Levin1,2,5,6. 1. Stanford University, Departments of Bioengineering, Stanford, CA, USA. 2. Stanford University, Departments of Radiology, Stanford, CA, USA. 3. Stanford University, Departments of Mechanical Engineering, Stanford, CA, USA. 4. Stanford University, Departments of Applied Physics, Stanford, CA, USA. 5. Stanford University, Departments of Electrical Engineering, Stanford, CA, USA. 6. Stanford University, Departments of Physics, Stanford, CA, USA.
Abstract
PURPOSE: A brain sized radio frequency (RF)-penetrable PET insert has been designed for simultaneous operation with MRI systems. This system takes advantage of electro-optical coupling and battery power to electrically float the PET insert relative to the MRI ground, permitting RF signals to be transmitted through small gaps between the modules that form the PET ring. This design facilitates the use of the built-in body coil for RF transmission and thus could be inserted into any existing MR site wishing to achieve simultaneous PET/MR imaging. The PET detectors employ nonmagnetic silicon photomultipliers in conjunction with a compressed sensing signal multiplexing scheme, and optical fibers to transmit analog PET detector signals out of the MRI room for decoding, processing, and image reconstruction. METHODS: The PET insert was first constructed and tested in a laboratory benchtop setting, where tomographic images of a custom resolution phantom were successfully acquired. The PET insert was then placed within a 3T body MRI system, and tomographic resolution/contrast phantom images were acquired both with only the B0 field present, and under continuous pulsing from different MR imaging sequences. RESULTS: The resulting PET images have comparable contrast-to-noise ratios (CNR) under all MR pulsing conditions: The maximum percent CNR relative difference for each rod type among all four PET images acquired in the MRI system has a mean of 14.0 ± 7.7%. MR images were successfully acquired through the RF-penetrable PET shielding using only the built-in MR body coil, suggesting that simultaneous imaging is possible without significant mutual interference. CONCLUSIONS: These results show promise for this technology as an alternative to costly integrated PET/MR scanners; a PET insert that is compatible with any existing clinical MRI system could greatly increase the availability, accessibility, and dissemination of PET/MR.
PURPOSE: A brain sized radio frequency (RF)-penetrable PET insert has been designed for simultaneous operation with MRI systems. This system takes advantage of electro-optical coupling and battery power to electrically float the PET insert relative to the MRI ground, permitting RF signals to be transmitted through small gaps between the modules that form the PET ring. This design facilitates the use of the built-in body coil for RF transmission and thus could be inserted into any existing MR site wishing to achieve simultaneous PET/MR imaging. The PET detectors employ nonmagnetic silicon photomultipliers in conjunction with a compressed sensing signal multiplexing scheme, and optical fibers to transmit analog PET detector signals out of the MRI room for decoding, processing, and image reconstruction. METHODS: The PET insert was first constructed and tested in a laboratory benchtop setting, where tomographic images of a custom resolution phantom were successfully acquired. The PET insert was then placed within a 3T body MRI system, and tomographic resolution/contrast phantom images were acquired both with only the B0 field present, and under continuous pulsing from different MR imaging sequences. RESULTS: The resulting PET images have comparable contrast-to-noise ratios (CNR) under all MR pulsing conditions: The maximum percent CNR relative difference for each rod type among all four PET images acquired in the MRI system has a mean of 14.0 ± 7.7%. MR images were successfully acquired through the RF-penetrable PET shielding using only the built-in MR body coil, suggesting that simultaneous imaging is possible without significant mutual interference. CONCLUSIONS: These results show promise for this technology as an alternative to costly integrated PET/MR scanners; a PET insert that is compatible with any existing clinical MRI system could greatly increase the availability, accessibility, and dissemination of PET/MR.
Authors: André Salomon; Benjamin Goldschmidt; René Botnar; Fabian Kiessling; Volkmar Schulz Journal: IEEE Trans Med Imaging Date: 2012-08-17 Impact factor: 10.048
Authors: Gaspar Delso; Sebastian Fürst; Björn Jakoby; Ralf Ladebeck; Carl Ganter; Stephan G Nekolla; Markus Schwaiger; Sibylle I Ziegler Journal: J Nucl Med Date: 2011-11-11 Impact factor: 10.057
Authors: Chen-Ming Chang; Alexander M Grant; Brian J Lee; Ealgoo Kim; KeyJo Hong; Craig S Levin Journal: Phys Med Biol Date: 2015-08-03 Impact factor: 3.609
Authors: Zhaolin Chen; Sharna D Jamadar; Shenpeng Li; Francesco Sforazzini; Jakub Baran; Nicholas Ferris; Nadim Jon Shah; Gary F Egan Journal: Hum Brain Mapp Date: 2018-08-04 Impact factor: 5.038
Authors: Brian J Lee; Alexander M Grant; Chen-Ming Chang; Ronald D Watkins; Gary H Glover; Craig S Levin Journal: IEEE Trans Med Imaging Date: 2018-03-13 Impact factor: 10.048