Pulse-echo imaging using a nondiffracting beam transducer

J. Y. Lu, J. F. Greenleaf

Research output: Contribution to journalArticlepeer-review

63 Scopus citations


Conventional ultrasonic transducers generate beams that diffract as they travel. This phenomenon causes images produced in B-mode to be degraded in the far-field of the transducers. Focused transducers are used to improve image quality. Unfortunately, focused transducers have short depth of field. Although multiple pulse transmissions focused at several depths are used to increase the effective depth of field, imaging frame rate is reduced dramatically leading to blurred images of moving objects such as the heart. We present a family of transducers that produce nondiffracting beams of large depth of field. Therefore, uniformly high resolution throughout the imaging area can be obtained without sacrificing the imaging frame rate. In addition, the nondiffracting property of these beams makes the correction for beam diffraction negligible in tissue characterization. This paper reports the results of computer simulations as well as in vitro and in vivo pulse-echo imaging experiments with a nondiffracting transducer. Images are compared to those obtained by conventional focused Gaussian shaded beam transducers and a commercial ACUSON 128 B-scanner. The new transducer has much longer depth of field with higher sidelobes than conventional transducers of the same aperture. Sidelobes can be reduced using the new transducer to transmit and the dynamically focused transducer to receive.

Original languageEnglish (US)
Pages (from-to)265-281
Number of pages17
JournalUltrasound in Medicine and Biology
Issue number3
StatePublished - 1991


  • Bessel beam
  • Calibration of receiver
  • Dynamic focusing
  • Gaussian beam
  • Nondiffracting beam
  • Nondiffracting transducer
  • Pulse-echo imaging
  • Tissue equivalent phantom
  • Tissue samples
  • Ultrasonic transducer

ASJC Scopus subject areas

  • Biophysics
  • Radiological and Ultrasound Technology
  • Acoustics and Ultrasonics


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