Electronic focusing of the ultrasonic beam by means of an annular array system

Downloads

Authors

  • T. WASZCZUK Institute of Fundamental Technological Research, Polish Academy of Sciences, Poland
  • T. KUJAWSKA Institute of Fundamental Technological Research, Polish Academy of Sciences, Poland
  • J. C. SOMER University of Limburg, Biophysics, Netherlands

Abstract

In conventional mechanical contact scanners the lateral resolution is inferior to the axial one. Improving the lateral resolution over a wide range of depth requires the use of a variable focusing system. We choose the phase annular array system which may be used in obstetrics and gynaecology. Calculations of the acoustical pressure were performed assuming pulse excited transducers. For the transmission the range of examination was divided into five focal zones. During reception the system permits dynamic focusing. Measurements of the ultrasonic beam were carried out. These results are in good agreement with calculations and indicate a considerable increase in the lateral resolution.

References

[1] L. FILIPCZYŃSKI, G. ŁYPACEWICZ, J. SAŁKOWSKI, T. WASZCZUK, Automatic eye vizualization and ultrasonic intensity determination on focused beams by means of electrodynamic and capacitance methods, Ultrasonics in Medicine Katzner et al. (eds.), Excerpta Medica, Amsterdam, Oxford, 1975.

[2] M. HUBELBANK, O. J. TRETIAK, Focused ultrasonic transducer design, M.I.T. Res. Lab. Elect. Q.P.R. 1971, 169-177.

[3] G. KOSSOFF et al., Annular phased arrays in ultrasonic obstetrical examinations, Advanced Study Institute, Ultrasonic Diagnostics, Milan, June 1974.

Most read articles by the same author(s)