At high fields, the RF (radiofrequency) transmit field distribution over the brain is no longer uniform, which may lead to an erroneous diagnosis.
I work on optimizing the RF energy deposition from multiple transmit channels to mitigate the non-uniformities in the RF transmit field while keeping the temperature rise in the human body under safety limits, even for infants.
We are developing methods for detecting and quantifying dangerous interactions, and then modifying the RF transmit field to eliminate the interactions by using an array of programmable transmit channels.
This so-called parallel transmission (pTx) configuration gives us the freedom to cancel out the non-uniformity of the transmit field by using a smart combination of the sensitivity profiles of each channel.
We present a survey of approaches to the design of one- and two-dimensional randomly rough surfaces that scatter or transmit light with specified angular, coherence, spatial, or wavelength properties of the scattered or transmitted field.
For comparable conditions, the computational speed for the transmit field of phased array using the Field II method as compared with the monopole approach was found to be at least an order of magnitude faster.
The system included a local WSN with multiple sensor nodes to acquire soil property data, a data sink, and a long-distance cellular network to transmit field data to a remote database.
Optimized pulses are designed to be effective over a specific range of frequency offsets and transmit field variations and are thus implementable regardless of field strength, transmit coil configuration, or the subject-specific spatial distribution of the static and RF fields.
RF shimming with the parallel-transmit coil produced significant advantages the transmit field was 38% more uniform than a traditional circularly polarized mode and 54% more power-efficient, demonstrating that parallel-transmit coils should be used for monkey imaging at ultrahigh field strengths.
The experimental results from phantom and human calf muscle demonstrate that the uHDC technique significantly enhanced RF magnetic transmit field (B1+) and reception field (B1−) and the gain could reach up to two folds in the tissue near the uHDC blocks.
