A Combined Clinical and Research Approach to the Problem of Ultrasound Visualization of Breast

Fry, Elizabeth Kelly; Fry, F. J.; Sanghvi, N. T.; Heimburger, Robert F.

doi:10.1007/978-1-4613-4443-8_92

Cited by 3 publications

(1 citation statement)

References 14 publications

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“…The main interest in this ultrasound modality resides in the possibility of creating well-delineated zones where high-frequency mechanical oscillations deliver a significant amount of energy. Trans-skull ultrasonic propagation has been proposed for tomography (Fry et al 1974, Carson et al 1977, Smith et al 1979, Dines et al 1981, Ylitalo et al 1990 and for blood perfusion detection (Kirkham et al 1986, Postert et al 2000. The therapeutic approaches that have been proposed cover thermal treatment of tumors (Fry 1977, Hynynen and Jolesz 1998, Tanter et al 1998, Tobias et al 1987, targeted drug delivery (Hynynen et al 2001), thrombolytic stroke treatment (Behrens et al 2001) and targeted antibody delivery (Kinoshita et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Treatment of near-skull brain tissue with a focused device using shear-mode conversion: a numerical study

Pichardo

Hynynen²

2007

Phys. Med. Biol.

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Shear mode transmission through the skull has been previously proposed as a new trans-skull propagation technique for noninvasive therapeutic ultrasound (Clement 2004 J. Acoust. Soc. Am. 115 1356-64). The main advantage of choosing shear over longitudinal mode resides on the fact that there is less wavefront distortion with the former. In the present study, the regions of the brain suitable for shear-mode transmission were established for a simple focused ultrasound device. The device consists of a spherically curved transducer that has a focal length of 10 cm, an aperture between 30 degrees and 60 degrees and operates at 0.74 MHz. The regions suitable for shear-mode transmission were determined by the shear wave acoustic windows that matched the shape of the device acoustic field. The acoustic windows were calculated using segmentation and triangulation of outer and inner faces of skull from 3D-MRI head datasets. Nine heads of healthy adults were analyzed. The surface considered for the calculations was the head region found above the supra-orbital margin. For every inspected point in the brain volume, the axis of the device was determined by the vector between this inspection point and a point located in the center of the brain. Numerical predictions of the acoustic field, where shear-mode conversion through the skull was considered, were obtained and compared to the case of water-only conditions. The brain tissue that is close to the skull showed suitable acoustic windows for shear waves. The central region of the brain seems to be unreachable using shear-mode. Analysis of the acoustic fields showed a proportional relation between the acoustic window for shear mode and the effective degree of focusing. However, this relation showed significant differences among specimens. In general, highly focused fields were obtained when the acoustic window for shear waves (A(SW)) intersected more than 67% of the entering acoustic window (A(TX)) of the device. The average depth from the inner surface of the skull showing this intersection value was 13 +/- 10 mm (mean +/- SD). The differences of the degree of focusing observed among patients suggest that the intersection A(SW) intersection A(TX) can be used as a preliminary criterion for screening and calculation of the acoustic fields should confirm the degree of focusing patient by patient. In conclusion, shear waves provide a useful method for trans-cranial focusing in regions close to the skull surface.

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Section: Introductionmentioning

confidence: 99%

Treatment of near-skull brain tissue with a focused device using shear-mode conversion: a numerical study

Pichardo

Hynynen²

2007

Phys. Med. Biol.

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A New Automated, High Resolution Ultrasound Breast Scanner

et al. 1979

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Ultrasound breast scanning has proved valuable in research settings but has not received widespread clinical usage due to the lack of suitable, commercially-available instruments. A new scanner designed for ultrasound breast screening has been developed with innovations in four areas: resolution, patient positioning, automation, and image storage and display. These innovations are described and representative scans are shown.

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An Annular Array System for High Resolution Breast Echography

et al. 1982

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Ultrasound B-mode imaging with electronically focused annular arrays has been associated in the past with fairly complex and expensive electronic circuits. When image quality rather than scanning speed is the prime concern, the concept of switched zone focusing offers an attractive alternative to true dynamic focusing previously reported. Strongly focused apertures used in both transmit and receive modes allow improved lateral resolution, lower side lobe levels, higher sensitivity, as well as simplified electronics.This approach was investigated for the particular case of breast imaging. We outline some general design considerations for water path imaging with annular arrays, and describe the system adopted in the development of a high resolution breast scanner using a sealed, water filled head. Experimental results are compared to theoretical predictions, and grey scale images are presented to illustrate the performance of the instrument.

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A Combined Clinical and Research Approach to the Problem of Ultrasound Visualization of Breast

Cited by 3 publications

References 14 publications

Treatment of near-skull brain tissue with a focused device using shear-mode conversion: a numerical study

Treatment of near-skull brain tissue with a focused device using shear-mode conversion: a numerical study

A New Automated, High Resolution Ultrasound Breast Scanner

An Annular Array System for High Resolution Breast Echography

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