Since the beginning of imaging, whether focusing a beam by a refractive lens or reflective lens, the intensity at and close to the acoustic axis of focusing all the beams have not been able to be focused to a distant, tight, three-dimensional (3D) probe due to the absence of or shallow convergence angle afforded by the beam. This limitation has resulted in the formation of an elongated, elliptical intensity profile along the acoustic axis of focusing all the beams with reduced intensity limiting the resolution of both 3D imaging and 3D analytical analyses of specimens. These focusing problems can be solved with the Reflecting Advanced Focusing Aperture lens accomplished using a 3D-shaped cone reflector having hyperbolic spline curves to focus acoustic waves to the distant 3D spot. After the acoustic wave reflects off the surface of the cone reflector, it then reflects off of a flat mirror to form the high-intensity, far-focused spot now able to be used as a probe for acoustic beams.

This thesis focuses on the design of the RAFA lens, designed for 10 cm focal length, to perform imaging and will give you a pleasant excursion of design formulation, sketches, simulation and experimental testing. The RAFA lens, both 3D printed and CNC machined, has been tested using a laser. Later, the lens is used to scan and image prostate phantom by measuring time using Software Defined Radio to calculate the speed of sound For a test run, the prostate phantom has been used for scanning.

Again, this imaging technique uses four major components:​ 1) RAFA lens, 2) a point piezoelectric detector, 3) an acoustic emitter (all submerged in a water bath with temperature of the water bath was maintained room temperature) and 4) Software Defined Radio (SDR) that sends Barkers code from the emitter and receives through the detector. Synchronizing the pattern of digits from Barkers code can enable the signal to be regenerated by the receiver with a low probability of error. Barkers code is used for pulse modulation to improve range resolution. The goal is the highest accuracy when measuring the delay of returned pulses which is determined by correlation. Barkers code has desirable correlation properties that produce very low side lobes. The longer the pattern the more accurately the data can be synchronized and errors due to distortion are omitted. For this research, a code length of 13 has been used.

The method we are using sends a plane acoustic beam from an emitter which is focused to a point virtual source with high intensity at 10 cm of focal length along the acoustic axis of focusing all the beams. One transmitter is used to send beam and another separate receiver to receive, both synchronized with SDR. The signal generated by the virtual source is picked up by the detector after traversing from the prostate phantom that carries information about the inner region of the prostate phantom and is then used to generate the image of the healthy and diseased regions.

The data to image healthy and diseased regions is collected by measuring the time difference for the acoustic beam to travel from emitter to detector with the use of the SDR. From the measured time, the speed of sound (SOS) is calculated and then used to generate the image of the healthy and diseased regions using the simplified Algebraic Reconstruction technique (ART).