Ultrasonic absorption and attenuation in mammalian tissues

Goss, S. A.; Frizzell, Leon A.; Dunn, F.

doi:10.1016/0301-5629(79)90086-3

Cited by 290 publications

(138 citation statements)

References 17 publications

Supporting

Mentioning

132

Contrasting

Order By: Relevance

“…Our previous study 7 showed that the attenuation coefficient values obtained with the novel method were significantly greater than those obtained with the SS method in fatty livers, but no significant differences were seen in normal and cirrhotic livers. Many reports [16][17][18][19][20] indicate that a power law function of the type α(f ) = α 0 f n describes the frequency dependence rather well. As in most reports, a linear frequency dependence of attenuation, that is, n = 1, was assumed in this study.…”

Section: Discussionmentioning

confidence: 99%

Attenuation Coefficient Measurement in the Thyroid

Fujii

Taniguchi

Itoh

et al. 2003

Journal of Ultrasound in Medicine

View full text Add to dashboard Cite

Objective. To assess the feasibility of a novel method of measuring the attenuation coefficient in the thyroid, which offers less variability of results than the conventional method. Methods. In our new method, the attenuation coefficient was evaluated on the basis of the following equation with sound field correction: . In our system, the attenuation coefficient was also evaluated by the spectral shift central frequency method at the same time. In this study, we used 32 cases of normal thyroid, 26 cases of Graves disease, and 11 cases of Hashimoto thyroiditis in the system. Results. With this novel method, attenuation coefficient values of the thyroid (mean ± SD) were 1.50 ± 0.26 dB · cm -1 · MHz -1 in the normal group, 0.91 ± 0.23 dB · cm -1 · MHz -1 in the Graves disease group, and 1.10 ± 0.27 dB · cm -1 · MHz -1 in the Hashimoto thyroiditis group. The novel method recorded a statistically significant difference between normal and diseased thyroids (P < .0001) and between Graves disease and Hashimoto thyroiditis groups (P = .0035). Statistical variation of the attenuation coefficient values obtained using the novel method was much smaller than that of those obtained by the spectral shift central frequency method in every group. Conclusions. This new method is considered usable for evaluating the attenuation coefficient of the thyroid in vivo.

show abstract

Section: Discussionmentioning

confidence: 99%

Attenuation Coefficient Measurement in the Thyroid

Fujii

Taniguchi

Itoh

et al. 2003

Journal of Ultrasound in Medicine

View full text Add to dashboard Cite

show abstract

“…Reported pressure amplitudes are estimates in vivo, taking into account this loss through the skull and ultrasound attenuation in the brain, with a mean attenuation coefficient of 5 Np/m/MHz. 32 The transducer was mounted on an MR-compatible positioning system and immersed in a tank of degassed water. Each rat was placed in the supine position on the sonication table in a 3-T clinical MRI scanner.…”

Section: Ultrasoundmentioning

confidence: 99%

Targeted delivery of doxorubicin to the rat brain at therapeutic levels using MRI‐guided focused ultrasound

Treat

McDannold

Vykhodtseva

et al. 2007

Intl Journal of Cancer

494

399

View full text Add to dashboard Cite

The clinical application of chemotherapy to brain tumors has been severely limited because antitumor agents are typically unable to penetrate an intact blood-brain barrier (BBB). Although doxorubicin (DOX) has been named as a strong candidate for chemotherapy of the central nervous system (CNS), the BBB often prevents cytotoxic levels from being achieved. In this study, we demonstrate a noninvasive method for the targeted delivery of DOX through the BBB, such that drug levels shown to be therapeutic in human tumors are achieved in the normal rat brain. Using MRI-guided focused ultrasound with preformed microbubbles (Optison) to locally disrupt the BBB and systemic administration of DOX, we achieved DOX concentrations of 886 6 327 ng/g tissue in the brain with minimal tissue effects. Tissue DOX concentrations of up to 5,366 6 659 ng/g tissue were achieved with higher Optison doses, but with more significant tissue damage. In contrast, DOX accumulation in nontargeted contralateral brain tissue remained significantly lower for all paired samples (p < 0.001). These results suggest that targeted delivery by focused ultrasound may render DOX chemotherapy a viable treatment option against CNS tumors, despite previous accessibility limitations. In addition, MRI signal enhancement in the sonicated region correlated strongly with tissue DOX concentration (r 5 0.87), suggesting that contrast-enhanced MRI could perhaps indicate drug penetration during image-guided interventions. Our technique using MRIguided focused ultrasound to achieve therapeutic levels of DOX in the brain offers a large step forward in the use of chemotherapy to treat patients with CNS malignancies. ' 2007 Wiley-Liss, Inc.

show abstract

“…In contrast, other investigators (Goss et al 1978(Goss et al , 1979(Goss et al , 1980 showed a large range of acoustic attenuation coefficients for bone tissue. The acoustic attenuation coefficient of bone is one of the crucial factors determining the distributions of SAR ratio in tissues.…”

Section: Resultsmentioning

confidence: 75%