Proceedings Article | 16 March 2006
KEYWORDS: Transducers, Ultrasonography, Flexible circuits, Apodization, 3D image processing, 3D acquisition, Prostate, Switches, Electrodes, Prostate cancer
In previous work, we investigated 3-D synthetic aperture imaging with 2-D array designs for real-time rectilinear volumetric imaging of targets near the transducer such as the breast and carotid artery. Here we present results for cylindrical 3-D imaging for 3-D transrectal ultrasound (TRUS). The major benefit of this design is the interconnect where an expensive multilayer flex circuit is no longer required. The interconnect uses a row-column addressing scheme to enable different groups of elements. Over 256 transmissions, this design is capable of synthesizing a 256 x 256 = 65,536 element fully sampled 2-D cylindrical array if desired. In receive, the echoes from individual elements along a row are recorded by the system receive channels. For faster volume acquisition time, we present a design where all elements of the 2-D array transmit simultaneously, and signals are recorded one row at a time. For a depth of 6 cm, a volume rate of 50 volumes/s can be achieved. We have performed computer simulations of a 10 MHz 256 x 256 synthetic cylindrical 2-D array with a radius of curvature of 10 mm to determine the radiation pattern. For an 128 x 128 subaperture, the on-axis case (x,y,z) = (0,0,20) mm showed a narrow beam down to -40 dB. In the transversal direction, on-axis lateral beamwidths at -6, -20, and -40 dB were 0.47 mm, 0.81 mm, and 2.54 mm, respectively. As for the longitudinal direction, the beamwidths are slightly narrower than in transversal direction, giving 0.39 mm, 0.72 mm, and 1.51 mm for the same corresponding dB levels.
