Resonance by rod-shaped reflectors in ultrasound test objects.

Hefner, Lance V.; Goldstein, A

doi:10.1148/radiology.139.1.7208920

Cited by 14 publications

(6 citation statements)

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“…In this case mechanical resonance (a collective vibration of the whole rod) occurs. 15 The resonance condition assures that all of the ultrasound energy in the rod has a definite collective time relationship. When the rod is positioned perfectly on a single element (also an acoustically resonant structure) constructive interference is assured and the test tool image is uniform.…”

Section: Discussionmentioning

confidence: 99%

Linear array test tool.

Goldstein

Ranney²,

McLeary³

1989

Journal of Ultrasound in Medicine

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A new linear array test tool is presented. It is easily used to directly measure an image acquisition parameter: the transmit/receive aperture. The aperture measurement gives important information concerning the functioning of the real-time multielement transducer and the equipment's signal-processing hardware and software. A feasibility test of the new test tool demonstrated that it can be easily used by clinical personnel to (1) determine the variation of the transmit/receive aperture with image depth; (2) document the operation of the equipment in each of the operator selectable focusing schemes; (3) perform quick checks of equipment performance when in doubt; and (4) test for and document the existence of nonfunctioning elements in linear, curved linear (convex), and phased arrays.

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Section: Discussionmentioning

confidence: 99%

Linear array test tool.

Goldstein

Ranney²,

McLeary³

1989

Journal of Ultrasound in Medicine

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“…Stainless steel type 302 rods 0.75 mm and 0.25 mm in diameter were used as reflectors in the test object. Through experimentation it was found that a center•to.-center distance of 2 em sufficed for the vertical set of rods, and, owing to beam 9 broadening effects, a 4-cm center-to-center distance sufficed for the horizontal rods. The configurations ofthe vertical rods and horizontal rods are indicated schematically in figure 2.…”

Section: Methodsmentioning

confidence: 99%

B-scan transducer peak frequency measurement by diffraction grating spectroscopy.

Goldstein¹

1982

Journal of Ultrasound in Medicine

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Making use of technology developed for optics, transmission diffraction grat· ing spectroscopy is proposed as a method of measuring ultrasound transducer frequencies. Diffraction grating theory is presented and extended to the case of a new test object proposed to measure a B·scan transducer's peak frequency. A prototype test object was built and its feasibility tested. The experimental results indicate that the test object performed well and has high measurement precision. The question of measurement accuracy was not resolved by the feasibility test. This complex point is discussed in detail. Recent improve· ments of the test object and the author's ongoing studies of diffraction grating characteristics are presented. (Key words: transducer frequency, diffraction grating, acceptance tests, routine performance tests, ultrasound quality assur· ance.)The frequency of an ultrasound transducer is a very important variable in an imaging system. The higher the frequency, the longer the focal length (for a constant diameter) and the better the image resolution in the focal zone, but the less the pene· tration into the patient. In pulse·echo clinical ultra· sound equipment, the transducer transmission pulse contains a bandwidth of frequencies that must be properly characterized in transducer acceptance tests and ongoing routine performance checks. It has been demonstrated that the transducer output frequency is sometimes affected by operator-selectable equipmentcontrols.1 This sensitivity of the system output frequency (transducer plus equipment electronics) can lead to changes in image resolution and patient penetration.Problems in medical imaging are sometimes solved by technology transfer of a proven technique in a related field. In searching for a method to mea· sure the transducer frequency, one is attracted to the frequency (or wavelength) measurement techniques used in the field of optics. A spec· trometer with a reflection diffraction grating is used to separate the light into its component wavelengths to facilitate the measurement of the wavelength (frequency) spectrum of the light. AI· though an ultrasound analog of the optical reflection diffraction grating spectrometer could be built toReceived from the Division of Medical Physics, Henry Ford Hospital, 2799 West Grand Boulevard, Detroit, Ml 48202.Address correspondence and reprint requests to Dr. Goldstein.measure the transducer frequency, the resulting in· strumentation would be large, expensive, cumbersome, and useful only in a laboratory staffed by experienced technical personnel. The use of diffrac· lion grating spectroscopy in diagnostic ultrasound could be a powerful technique for measuring the transducer frequency. It is thus enticing to search for a test object application of the diffraction grating principle that could be used easily in a clinical set· tin g. In this paper we present the concept of a new transducer frequency test object that uses transmis· sion diffraction grating spectroscopy. The theory of diffraction grating operation is presente...

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“…They can also be caused by metal parts, such as clips, pellets, and projectiles, possibly by gas bubbles and the lung surface [28], where they are also called "B-lines" and are used as a diagnostic criterion. Hefner and Goldstein [29] describe artifacts caused by resonance at rod-shaped reflectors that are similar to comet-tail artifacts.…”

Section: Comet-tail Artifactmentioning

confidence: 99%

“…und an der Lungenoberfläche [28], wo sie auch "B-lines" genannt und als diagnostisches Kriterium verwendet werden. Hefner und Goldstein [29] beschreiben durch Resonanz an Stahldrähtchen entstehende Schweifartefakte, die ähnlich wie Comet tail-Artefakte aussehen.…”

Section: Summary !unclassified

Ultrasound Artifacts – Part 1

Bönhof¹

2015

Ultraschall in Med

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Knowledge of artifacts is essential for the competent use of ultrasound. Artifacts are method-based and should be differentiated from image errors of another genesis. They are logical and occur because the conditions required for image generation do not fully correspond to the reality. Artifacts occur due to disregard of the true dimensions of sound lobes (slice-thickness artifacts and bow artifacts, range ambiguities) and due to different types of mirroring with different appearances. There are also comet-tail-like artifacts such as comet-tail and ring-down artifacts.

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Resonance by rod-shaped reflectors in ultrasound test objects.

Cited by 14 publications

References 0 publications

Linear array test tool.

Linear array test tool.

B-scan transducer peak frequency measurement by diffraction grating spectroscopy.

Ultrasound Artifacts – Part 1

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