Aaron R Purchase1,2, Tadeusz Pałasz3, Hongwei Sun4,5, Jonathan C Sharp4,5, Boguslaw Tomanek4,5,6. 1. Department of Oncology, University of Alberta, 11560 University Avenue, Edmonton, AB, T6G 1Z2, Canada. apurchas@ualberta.ca. 2. Division of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB, T6G 1Z2, Canada. apurchas@ualberta.ca. 3. Marian Smoluchowski Institute of Physics, Jagiellonian University, Stanislawa Łojasiewicza 11, 30-348, Kraków, Poland. 4. Department of Oncology, University of Alberta, 11560 University Avenue, Edmonton, AB, T6G 1Z2, Canada. 5. Division of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB, T6G 1Z2, Canada. 6. Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, Kraków, Poland.
Abstract
OBJECTIVE: A radiofrequency (RF) power amplifier is an essential component of any magnetic resonance imaging (MRI) system. Unfortunately, no commercial amplifier exists to fulfill the needs of the transmit array spatial encoding (TRASE) MRI technique, requiring high duty cycle, high RF output power and independently controlled multi-channel capability. Thus, an RF amplifier for TRASE MRI is needed. MATERIALS AND METHODS: A dual-channel RF power amplifier dedicated for TRASE at 0.22 T (9.27 MHz) was designed and constructed using commercially available components. The amplifier was tested on the bench and used a 0.22 T MRI system with a twisted solenoid and saddle RF coil combination capable of a single-axis TRASE. RESULTS: The amplifier is capable of sequential, dual-channel operation up to 50% duty cycle, 1 kW peak output and highly stable 100 μs RF pulse trains. High spatial resolution one-dimensional TRASE was obtained with the power amplifier to demonstrate its capability. CONCLUSION: The constructed amplifier is the first prototype that meets the requirements of TRASE rectifying limitations of duty cycle and timing presented by commercial RF amplifiers. The amplifier makes possible future high resolution in vivo TRASE MRI.
OBJECTIVE: A radiofrequency (RF) power amplifier is an essential component of any magnetic resonance imaging (MRI) system. Unfortunately, no commercial amplifier exists to fulfill the needs of the transmit array spatial encoding (TRASE) MRI technique, requiring high duty cycle, high RF output power and independently controlled multi-channel capability. Thus, an RF amplifier for TRASE MRI is needed. MATERIALS AND METHODS: A dual-channel RF power amplifier dedicated for TRASE at 0.22 T (9.27 MHz) was designed and constructed using commercially available components. The amplifier was tested on the bench and used a 0.22 T MRI system with a twisted solenoid and saddle RF coil combination capable of a single-axis TRASE. RESULTS: The amplifier is capable of sequential, dual-channel operation up to 50% duty cycle, 1 kW peak output and highly stable 100 μs RF pulse trains. High spatial resolution one-dimensional TRASE was obtained with the power amplifier to demonstrate its capability. CONCLUSION: The constructed amplifier is the first prototype that meets the requirements of TRASE rectifying limitations of duty cycle and timing presented by commercial RF amplifiers. The amplifier makes possible future high resolution in vivo TRASE MRI.
Authors: Jonathan C Sharp; Donghui Yin; Richard H Bernhardt; Qunli Deng; Andrew E Procca; Randy L Tyson; Kan Lo; Boguslaw Tomanek Journal: Rev Sci Instrum Date: 2009-09 Impact factor: 1.523
Authors: Jason P Stockmann; Clarissa Z Cooley; Bastien Guerin; Matthew S Rosen; Lawrence L Wald Journal: J Magn Reson Date: 2016-04-08 Impact factor: 2.229