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J W Hunt

Publications and source records attributed to J W Hunt.

At least 91 records · Page 5Linked to original sources
PubMed1934

MISS METTA LOOMIS.

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Journal Article↗
PubMedDate not supplied

Breast imaging with a conical transducer/annular array hybrid scanner.

A hybrid conical scanner consisting of a 37.5 degrees, 4 MHz conical receiver and a five element 5 cm dia. 4 MHz annular array transmitter has been developed for breast imaging. The ultrasound fields and imaging characteristics of three interesting geometries are compared. These are: (1) the annular array used in conventional pulse-echo mode, (2) the conical transducer used in combination with the full annular array and (3) the conical transducer used in combination with the center element of the annular array (simple conical scanner). Both conical systems provide extremely narrow (0.3 mm) beamwidths at -6dB but the cone/annular array combination has significantly improved sidelobe characteristics compared with the simple conical scanner. The combination of high resolution and reasonable sidelobe levels for the cone/annular array hybrid results in images with very fine speckle patterns and good definition of small structures. Breast images from young normal volunteers show that this approach has considerable potential for clinical application.

Adult↗
PubMedDate not supplied

Artifactual echoes in B-mode images due to multiple scattering.

In B-mode images, echoes, which appear to arise from inherently anechoic regions due to scattering from neighbouring echogenic regions, can be considered artifactual. We have observed multiple scatter contributions to such artifactual echoes in images of plane boundaries between random scattering phantoms and anechoic regions. For the strongest scattering phantom studied, multiple scatter echoes were 3-9% of the average phantom signal using two sharply focused transducers, an annular array in pulse echo mode, and an annular array/cone hybrid. Multiple scatter was less than 5% for a conventional transducer. Echo amplitudes were also measured in normal excised human liver and breast tissue. It was estimated that artifactual echoes due to multiple scatter would be negligible in B-mode images of liver. However, for breast imaging, the level of artifactual echoes was estimated to be similar to that found for our strongest scattering phantom.

Breast↗