In this paper, using finite element modeling, we investigate the possibility of using diffraction effects to focus and amplify ultrasonic waves via the placement of silicon beads in the body (water is used as the medium here for simplicity). We show that pressure waves are amplified and localized when specifically sized beads are placed, and the effects of amplification are seen even when the bead is not in line with the ultrasonic transducer, although optimum amplification results when the bead is exactly inline with the transducer. We also show that we can use stereo microphones to detect the specific location of the bead in relation to the pulse transducer so that precise control is possible for linear alignment to maximize pressure amplification. This work is motivated by the need to seek more efficient and less invasive ways of stimulating the vagus nerve in the human body, and has many applications in medicine.