New equipment and transducers for ophthalmic diagnosis

Buschmann, W.

doi:10.1016/0041-624x(65)90234-9

Cited by 10 publications

(4 citation statements)

References 4 publications

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“…It was probably Buschman (1965) who first used an array of transducers to produce an ultrasonic image. His probe had ten small transducers mounted on an arc-shaped support designed to fit over the eye.…”

Section: Transducer Array Scanningmentioning

confidence: 99%

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Ultrasonic imaging of the human body

Wells

1999

Rep. Prog. Phys.

160

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Ultrasonic imaging is a mature medical technology. It accounts for one in four imaging studies and this proportion is increasing. Wave propagation, beam formation, the Doppler effect and the properties of tissues that affect imaging are discussed. The transducer materials and construction of the probes used in imaging are described, as well as the methods of measuring the ultrasonic field. The history of ultrasonic imaging is briefly reviewed. The pulse-echo technique is used for real-time grey-scale imaging and the factors that limit the spatial and temporal resolutions are considered. The construction and performance of transducer arrays are discussed, together with the associated beam steering and signal processing systems. Speckle and scattering by blood are introduced, particularly in the context of the observation of blood flow by means of the Doppler effect and by time-domain signal processing. Colour flow imaging, and the colour coding schemes used for velocity and power imaging, are explained. The acquisition and display of three-dimensional images are discussed, with particular reference to speed and segmentation. Specialized imaging methods, including endoluminal scanning, synthetic aperture imaging, computed tomography, elasticity imaging, microscanning, contrast agents, and tissue harmonic imaging, are reviewed. There is a discussion of issues relating to safety. Conclusions are drawn and future prospects are considered.

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Section: Transducer Array Scanningmentioning

confidence: 99%

“…In what can now be seen to be a natural extension of Buschman's (1965) array of transducers, Bom et al (1971Bom et al ( , 1973 constructed linear arrays with 20 transducer elements. Overall, the probe face was 80 mm long and 10 mm wide.…”

Section: Transducer Array Scanningmentioning

confidence: 99%

Ultrasonic imaging of the human body

Wells

1999

Rep. Prog. Phys.

160

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“…Phased arrays have long been used for diagnostic US (e.g. Buschmann 1965) and are more recently rising in prominence for therapy as well. In terms of clinical HIFU phased arrays, InSightec offers ExAblate 2000 (Tempany et al 2003), a commercial, FDA-approved device, while Philips Healthcare offers Sonalleve MR-HIFU (Enholm et al 2010), a comparable, CE-approved device.…”

Section: Introductionmentioning

confidence: 99%

The utility of sparse 2D fully electronically steerable focused ultrasound phased arrays for thermal surgery: a simulation study

et al. 2011

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Sparse arrays are widely used in diagnostic ultrasound for their strong performance and relative technical simplicity. This simulation study assessed the efficacy of phased arrays of varied sparseness for thermal surgery, especially with regard to power consumption and near-field heating. It employs a linear ultrasound propagation model and a semi-analytical solution to the Pennes' bioheat transfer equation. The basic design had 4912 cylindrical transducers (500 kHz) arranged on a flat 12 cm disk (1.5 mm spacing). This array was compared to randomly-thinned sparse arrays with 75%, 50% and 25% populations. Temperature elevations of 60 and 70 °C were induced in sonication times of 5-20 s, at foci spanning depths of 50-150 mm and radii of 0-60 mm. The sparse arrays produced nearly indistinguishable focal patterns but, averaged across the foci, required 132%, 200% and 393% of the power of the full array, respectively, applied through fewer transducer elements. Comparable results were found at 1 MHz from equivalent arrays. Simulated lesions were formed (thermal dose ⩾ 240 equivalent minutes at 43 °C (T(43))) and 'transition' and 'unsafe' regions (both defined as 5 min < T(43) < 240 min) were identified, the former immediately surrounding the lesion and the latter anywhere else. At a depth of 100 mm, sparse arrays were found to produce comparable lesions to the full array at the focus, but 'unsafe', over-heated near-field regions after some ablated lesion volume: about 12 mL for the 25% array, around 100 mL for the 50% array, while the 75% and full arrays produced 150 mL lesions safely.

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“…In figure 4 the system is shown in an in vitro demonstration. The transducer was positioned before a cylinder gauze suspended in a water tank.…”

Section: The Multiscan Systemmentioning

confidence: 99%

Multiscan Echocardiography

et al. 1973

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The principle of a prototype multiple element echocardiographic instrument is described. The major goal of this system is instantaneous visualization of moving cross-sections of the heart. As a result a direct impression of cardiac anatomy and dimensions may be obtained. The transducer contains 20 small acoustic elements positioned in a row. System characteristics and transducer details are given. A flexible five lever time-gain compensation unit which permits independent gain setting for specific depth ranges is described. Recording modes include video tape, photographic, film and line scan techniques. The signal from any selected element of the Multiscan transducer may be recorded in the conventional time-motion display, thus combining Multiscan capabilities with conventional echocardiographic techniques.

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New equipment and transducers for ophthalmic diagnosis

Cited by 10 publications

References 4 publications

Ultrasonic imaging of the human body

Ultrasonic imaging of the human body

The utility of sparse 2D fully electronically steerable focused ultrasound phased arrays for thermal surgery: a simulation study

Multiscan Echocardiography

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