Computerized Ultrasonic Tomography by Electronic Scanning and Steering of a Ring Array
In order to realize a rapid and accurate in-vivo scanner for breast imaging, a novel technique using a 450 elements −360° ring array has been developed. Every mechanical motions during recording have been thus entirely eliminated, all the tomographic projections being obtained by electronically scanning the array. The electronics implemented feature a computer-controlled steering of the ultrasonic beam as previously reported and an electronic ring multiplexer having now reached completion. Although data are recorded sequentially with one projection at a time, tomographic records can be achieved within two seconds by scanning first the tomographic angle θ (constant K mode) rather than the projection indice K (constant θ mode).Shorter recording times could be achieved with the realized multiplexer which can accept several recording channels for fan beam tomography. A 3.5 MHz ring array is reaching completion and has been built in five separate 72°–90 elements arrays which are then assembled to realize the whole ring array. One of this 90 elements sector has already been fully realized and its manufacturing steps are described. Tomographic computer reconstructions of a rubber phantom insonified with a 12 elements test array are reported.
KeywordsBreast Imaging Narrow Beam Ultrasonic Beam Projection Indice Acoustical Holography
Unable to display preview. Download preview PDF.
- Chivers, R.C., and Hill, C.R., 1975, Ultrasonic attenuation in human tissue, Ultr. Med. & Bio1, 2: 25–29.Google Scholar
- Clément, M. and Alais, P., 1978, French Patent n°78 18 424.Google Scholar
- Clément, M., Alais, P., Perrin, J., 1979, Ultrasonic computed tomography by electronic scanning of an annular array, Ultrasonics International 79 Proc., 511–517.Google Scholar
- Dale, G., Gairard, B., Gros, D., 1980, Numerical analysis of breast echotomograms, in: “Investigative Ultrasonology”, C.R. Chivers and Alvisi, ed., Pitman medical Press, London.Google Scholar
- Glover, G. H., 1977, Computerized time-of-flight ultrasonic tomography for breast examination, Ultra. Med & Biol, 3: 117–127.Google Scholar
- Greenleaf, J. F., Johnson, S.A., Lee, S.L., Herman, G.T.,and Wood, E.H., 1974, Algebraic reconstruction of spatial distributions of acoustic absorption within tissue from their 2-D acoustic projections, in:“Acoustical Holography,” vol 5, P.S. Green, ed.,Plenum Press, New York.Google Scholar
- Greenleaf, J.F., Johnson, S.A., Samayoa, W.F., and Duck, F.A., 1975, Algebraic reconstruction of spatial distributions of acoustic velocities in tissue from their time-of-flight profiles, “Acoustical Holography”, Vol 6, N. Booth, ed., Plenum Press, New York.Google Scholar
- Greenleaf, J.F., Kenue S.K., Rajagopalan, B., Bahn, R.C., and Johnson, S.A., 1980, Breast imaging by ultrasonic computer assisted tomography, “Acoustical Imaging”,Vol 8 A. Metherell, ed., Plenum Press, New York.Google Scholar
- Griffitns,’K., 1978, Ultrasound examination of the breast, Med. Ultr., 2: 13–19.Google Scholar
- Kossof, G., Fry, EM., and Jellins, J., 1973, Average velocity of ultrasound in the human female breast, J.A.S.A., 53: 1730–1736.Google Scholar
- O’Brien, W.D.,1977, The role of collagen in determining ultrasonic propagation properties in tissue, “Acoustical Holography”, Vol 7, L.W. Kessler, ed., Plenum Press, New-York.Google Scholar
- Wells, P.N.T., 1975, Absorption and dispersion of ultrasound in biological tissue, Ultr. Med. & Biol, 1. 369–376.Google Scholar