High-speed data acquisition in a diffraction tomography system employing large-scale toroidal arrays
✍ Scribed by Michael P. André; Helmar S. Janée; Peter J. Martin; Gregory P. Otto; Brett A. Spivey; Douglas A. Palmer
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 474 KB
- Volume
- 8
- Category
- Article
- ISSN
- 0899-9457
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✦ Synopsis
This report describes the development of an experimenyet, the basic process of image formation has remained the same: tal system for ultrasound computed tomography and its application Imaging systems record the amplitude of backscattered signals to breast imaging. Details of the system design and methods of highfrom inhomogeneities in the acoustic impedance of tissues. An speed data acquisition are presented. The method uses low-power image is produced by assuming straight-line propagation, a mean discrete frequency sound in the range of 0.3-1.2 MHz, two cylindrical sound speed in tissue of 1540 m s 01 , and by computing the depth arrays of 512 and 1024 PZT transducers, high spatial sampling of the of ''echogenic'' structures based on the round-trip delay time. wavefront, and unique diffraction tomographic reconstruction meth-With the exception of Doppler techniques for blood flow, phase ods. One transducer at a time is activated and allowed to reach steady or frequency information is not measured and the angle of destate at which point the remaining measure phase and amplitude of tected scatter is limited to near 180Њ. the ultrasound signal. A total of 64 MB of data are acquired in õ1 s for the 512-element array and 128 MB in õ3 s for the 1024 array. This article describes an ultrasound system based on the prin-Several algorithms have been developed to produce the diffraction ciples of diffraction tomography which attempts to reconstruct tomogram which is reconstructed as either a 512 1 512 or 1024 1 an image from the scattered acoustic field with consideration of 1024 matrix of the scattering potential of the object dependent on diffraction effects by utilizing approximations to the wave equaspeed of sound and attenuation. The effects of aberration are greatly tion. The system employs large 20-cm toroidal arrays and a highdiminished by a hybrid iterative algorithm. To date, human images speed data acquisition system that is able to record the entire have been made of the female breast which show good depiction of scatter field around an object [1]. The system has successfully glandular structures and differentiation of gland and fat, and the coronal format provides a novel of the entire breast in life-size display. The imaged female volunteers with a wide range of breast sizes and results demonstrate that the technique provides a unique quantitative types and the results show promise for continued diagnostic evalultrasound image with high resolution over a very large global field uation and the potential for quantifying tissue acoustic properof view of the breast. The method shows promise for improved imties [2,3].