Noncontact Radio Frequency (RF) Induced Ultrasound in the Brain

A noninvasive pulsed microwave phased array for transcranial thermoacoustic ultrasound wave generation in the brain is explored using a phantom. The microwave antenna consists of a 4-element helical monopole array transmitting at 2 GHz into a cylindrical head phantom with brain tissue equivalent material. With the microwave array transmitting in pulsed mode, the brain phantom surface is heated, and the thermally induced acoustic wave is measured with an ultrasound medical transducer. In principle, this acoustic wave can be detected and the brain tissue imaged with a noninvasive optical imaging system.