Department of Oncology, University of Alberta, 11560 University Avenue, Edmonton, AB, T6G 1Z2, Canada.
Division of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB, T6G 1Z2, Canada.
MAGMA. 2019 Dec;32(6):679-692. doi: 10.1007/s10334-019-00763-1. Epub 2019 Jun 20.
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.
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.
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.
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.
射频 (RF) 功率放大器是任何磁共振成像 (MRI) 系统的重要组成部分。不幸的是，没有满足发射阵空间编码 (TRASE) MRI 技术需求的商用放大器，该技术需要高占空比、高 RF 输出功率和独立控制的多通道能力。因此，需要一种用于 TRASE MRI 的 RF 放大器。
使用市售组件设计并构建了一个专用于 TRASE 在 0.22T（9.27MHz）的双通道 RF 功率放大器。该放大器在台架上进行了测试，并在具有扭曲螺线管和鞍形 RF 线圈组合的 0.22T MRI 系统上使用，该系统能够进行单轴 TRASE。
该放大器能够以 50%的占空比、1kW 的峰值输出和高度稳定的 100μs RF 脉冲序列进行顺序、双通道操作。使用功率放大器获得了高空间分辨率的一维 TRASE，证明了其性能。
所构建的放大器是第一个满足 TRASE 对商用 RF 放大器的占空比和定时限制的要求的原型。该放大器为未来的高分辨率体内 TRASE MRI 铺平了道路。
