A three-dimensional (3D) transrectal ultrasound (TRUS) imaging system is presented in this paper. The 3D imaging system is used for diagnosing diseases of prostate. The 3D image is reconstructed by a series of two-dimensional image data which is obtained through rectum. It can be a guide to prostate needle biopsies. The system is built by two parts: hardware and software. In the hardware, the mechanical device, stepper motor, control circuit, B Mode TRUS and personal computer (PC) workshop are presented. The software includes the firmware of micro control unit and software of the PC workshop. In order to evaluate the performance of the 3D imaging system, we did experiments with water and agar phantoms, and the results demonstrated the system's ability of 3D imaging with high-precision.
Ultrasound diffraction tomography (UDT) possesses the characteristics of high resolution, sensitive to dense tissue, and has high application value in clinics. To suppress the artifact and improve the quality of reconstructed image, classical interpolation method needs to be improved by increasing the number of projections and channels, which will increase the scanning time and the complexity of the imaging system. In this study, we tried to accurately reconstruct the object from limited projection based on compressed sensing. Firstly, we illuminated the object from random angles with limited number of projections. Then we obtained spatial frequency samples through Fourier diffraction theory. Secondly, we formulated the inverse problem of UDT by exploring the sparsity of the object. Thirdly, we solved the inverse problem by conjugate gradient method to reconstruct the object. We accurately reconstructed the object using the proposed method. Not only can the proposed method save scanning time to reduce the distortion by respiratory movement, but also can reduce cost and complexity of the system. Compared to the interpolation method, our method can reduce the reconstruction error and improve the structural similarity.