Sector-scanning 3D ultrasound imaging in frequency domain with 1D array transducer

Sector-scanning is a conventional scanning mode in ultrasound imaging, which can increase the area to observe. In three-dimensional (3D) ultrasound, freehand imaging system is usually used. This method uses a moving elevation focused one-dimensional (1D) transducer to construct a series of B-mode slice images, and then these B-mode slice images are combined to form a 3D volume image. When sector-scanning is used to acquire the B-mode slices, the elevation resolution is poor because of the elevation resolution of the probe and the interpolations between the slices. In this paper, based on the linear scanning method in our previous work, a sector-scanning 3D imaging method is proposed. In this imaging method, a linear array transducer without elevation focusing is also used, and the 1D transducer transmits limited diffraction beams and receives echo signals repeatedly when rotated around an axis parallel to the transducer. After finishing the scanning, all the received signals are combined to construct the 3D image in frequency domain with Fourier transform. Simulation results show that the new method can construct the 3D image effectively. Compared with the imaging method based on B-mode slices, the new method can improve the elevation resolution significantly. The elevation resolution can be promoted to less than 2 mm with the imaging depth 100 mm by one transmission at each position. Besides, because only one transmission is needed at each position, the frame rate can be increased to some extent.