Title :
Ultrasonic nondiffracting transducer for medical imaging
Author :
Lu, Jian-Yu ; Greenleaf, James F.
Author_Institution :
Biodynamics Res. Unit, May Clinic, Rochester, MN, USA
Abstract :
The nondiffracting J/sub 0/ Bessel beam is evaluated, and its application to medical imaging is suggested. Computer simulations and experimental results for a ten-ring annular Bessel shaded transducer are described. Both continuous-wave (CW) and pulse-wave (PW) excitations are shown and compared to conventional Gaussian beams. The nondiffracting beam has about 1.27-nm radius main lobe with a 20-cm depth of field compared to the Gaussian transducer of the same size with a 1.27-mm radius main lobe at a focus of 12 cm and 2*4-cm depth of field. The side lobes of the nondiffracting beam are the same as the J/sub 0/ Bessel function. The effects of heterogeneity due to tissue on the nondiffracting beam and on the focused Gaussian beam are also reported.<>
Keywords :
biomedical ultrasonics; ultrasonic transducers; 1.27 nm; 20 cm; continuous wave excitation; depth of field; main lobe radius; medical imaging; nondiffracting J/sub 0/ Bessel beam; pulse wave excitation; side lobes; ten-ring annular Bessel shaded transducer; tissue heterogeneity effects; ultrasonic transducer; Apertures; Biomedical imaging; Biomedical optical imaging; Biomedical transducers; Equations; Focusing; Gaussian processes; Image resolution; Optical beams; Ultrasonic transducers;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
