Development and characterization of a tissue-mimicking material for high-intensity focused ultrasound

King, Randy L.; Liu, Yunbo; Maruvada, Subha; Herman, Bruce A.; Wear, Keith A.; Harris, Gerald R.

doi:10.1109/tuffc.2011.1959

Cited by 55 publications

(78 citation statements)

References 30 publications

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“…Phase change due to displacement was separated from that due to temperature by complex subtraction of an interleaved volume acquired with no FUS applied. Temperature was obtained using the proton resonance frequency method with a referenceless background phase subtraction [6]. Experiments were performed in a gelatin phantom and excised pig brain on 3 T MRI scanners (Siemens Tim Trio and PrismaFit).…”

Section: Resultsmentioning

confidence: 99%

“…For each cycle, six in total, patients will receive a combination of ThermoDox and HIFU-induced hyperthermia followed by cyclophosphamide. All MR-HIFU experiments will be performed on a dedicated breast MR-HIFU system (Philips Healthcare, Vantaa, Finland) integrated with a clinical 1.5 T MRI scanner (Achieva, Philips Healthcare, Best, The Netherlands) [6,7]. Four to six weeks after finishing the last cycle of chemotherapy the patients will undergo surgery.…”

Section: A133mentioning

confidence: 99%

“…[5] The muscle tissue will be mimicked by a hightemperature hydrogel matrix (gellan gum) combined with different sizes of aluminum oxide particles and other chemicals. [6] Experiment: MR-HIFU experiment will be performed using a clinical HIFU system (InSightec, Ltd., Israel) installed in a 1.5 Tesla MRI scanner (GE Healthcare, USA). HIFU beam will be applied as shown in Fig.…”

Section: A165mentioning

confidence: 99%

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5th International Symposium on Focused Ultrasound

Zaaroor¹,

Sinai²,

Goldsher³

et al. 2016

J Ther Ultrasound

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Objectives Essential Tremor (ET) is one of the most common neurologic conditions, and conservative measures are frequently suboptimal. Recent data from a multi-institution, randomized controlled clinical trial demonstrated that Magnetic Resonance-guided Focused Ultrasound (MRgFUS) thalamotomy improves upper limb tremor in medically refractory ET. This study assesses the cost-effectiveness of this novel therapy in comparison to existing procedural options. Methods PubMed and Cochrane Library searches were performed for studies of MRgFUS, Deep Brain Stimulation (DBS), and Stereotactic Radiosurgery (SRS) for ET. Pre-and post-operative tremor-related disability scores were collected from 32 studies involving 83 MRgFUS, 615 DBS, and 260 SRS cases. Utility (defined as percent change in functional disability) was calculated, and Medicare reimbursements were collected as a proxy for societal cost -costs of MRgFUS for ET were derived from a combination of available costs of approved indications and SRS costs where appropriate. A decision and cost-effectiveness analysis was then constructed, implementing meta-analytic techniques. Results MRgFUS thalamotomy resulted in significantly higher utility scores compared with DBS and SRS based on estimates of Medicare reimbursement (p < 0.001). MRgFUS was also the most inexpensive procedure out of the three (p < 0.001). Conclusions Preliminary experience with MRgFUS for ET suggests that this novel therapeutic may be more effective than available alternatives and potentially less costly for society. It thus will likely "dominate" DBS and SRS as a more cost-effective option for medically refractory ET. Our findings support further investigation of MRgFUS for ET and broad adoption. Objectives The ventral intermediate nucleus (VIM) is not visible on conventional Magnetic Resonance Imaging (MRI).A novel method for tractography-based VIM identification has recently been described. We report the short-term clinical results of prospective VIM targeting with tractography in a cohort of patients undergoing Focused Ultrasound thalamotomy. Methods All patients underwent structural and diffusion weighted imaging (60 diffusion directions, 2 mm isovoxel) with 3 Tesla MRI scanner (Philips Ingenia CX). The images were processed using streamline tractography (Stealth Viz, Medtronic Inc.). The lateral and posterior borders of VIM were defined by tracking the pyramidal tract and medial lemniscus respectively. A VIM region of interest (ROI) was placed 3 mm away from these borders (Figs. 1, 2 and 3). The structural connectivity of this VIM ROI was confirmed to the motor cortex (M1) and cerebellum. The coordinates of tractography-based VIM in relation to posterior commissure were noted for surgical targeting. The parameters analyzed include a clinical tremor scale (pre-, intraoperative, and post operative), operative time, and number of sonications. Results Tractography-based VIM targeting was successful in 7 out of 8 patients. The coordinates of tractography-based VIM were significantly different from...

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Section: Resultsmentioning

confidence: 99%

Section: A133mentioning

confidence: 99%

Section: A165mentioning

confidence: 99%

See 1 more Smart Citation

5th International Symposium on Focused Ultrasound

Zaaroor¹,

Sinai²,

Goldsher³

et al. 2016

J Ther Ultrasound

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“…[26][27][28][29] TMM phantoms bridge the gap in translational research without the need of direct experimentation on humans or animals. The phantoms designed with TMMS are essential for assessing different technologies, and for training and research.…”

Section: Introductionmentioning

confidence: 99%

“…Various kinds of TMMs have already been used in ultrasound research, such as gelatine, agar, silicone, and polyacrylamide (PAA) gel. [26][27][28][29] The key parameters in material characterization for ultrasound imaging include the acoustic velocity, the acoustic impedance, and the acoustical attenuation, while Young's modulus is an important parameter for elastography phantoms. Madsen et al 30 have demonstrated the use of TM phantoms for standardization of both ultrasound imaging of the prostate 26 and for elastographic imaging 18, 31 using agar and gelatine materials.…”

Section: Introductionmentioning

confidence: 99%

Tissue mimicking materials for the detection of prostate cancer using shear wave elastography: A validation study

et al. 2013

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Purpose: Quantification of stiffness changes may provide important diagnostic information and aid in the early detection of cancers. Shear wave elastography is an imaging technique that assesses tissue stiffness using acoustic radiation force as an alternate to manual palpation reported previously with quasistatic elastography. In this study, the elastic properties of tissue mimicking materials, including agar, polyacrylamide (PAA), and silicone, are evaluated with an objective to determine material characteristics which resemble normal and cancerous prostate tissue. Methods: Acoustic properties and stiffness of tissue mimicking phantoms were measured using compressional mechanical testing and shear wave elastography using supersonic shear imaging. The latter is based on the principles of shear waves generated using acoustic radiation force. The evaluation included tissue mimicking materials (TMMs) within the prostate at different positions and sizes that could mimic cancerous and normal prostate tissue. Patient data on normal and prostate cancer tissues quantified using biopsy histopathology were used to validate the findings. Pathologist reports on histopathology were blinded to mechanical testing and elastographic findings.

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Ultrasound assessment of the conversion of sound energy into heat in tissue phantoms enriched with magnetic micro‐ and nanoparticles

et al. 2019

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Purpose Nowadays, the improvement of ultrasonic hyperthermia therapy is often achieved by adding hard particles to the sonicated medium in order to increase the heating efficiency. The explanation of the phenomenon of ultrasonic heating still requires testing on tissue mimicking materials (TMMs), enriched with particles of different sizes and physical properties. Our goal was to determine, by comparing their quantitative acoustic properties, which TMMs, with magnetic micro‐ or nanoparticles, convert more ultrasonic energy into heat or which of the particles embedded in the agar gel act as more effective thermal sonosensitizers. Methods We manufactured a pure agar gel and an agar gel with the addition of magnetic micro‐ or nanoparticles in two proportions of 8 and 16 mg/ml. Ultrasound quantitative techniques, the broadband reflection substitution technique and backscattered spectrum analysis were used to characterize the samples by speed of sound (SOS), frequency‐dependent attenuation, and backscattering coefficients. The integrated backscattering coefficients were also calculated. The quantitative parameters, scattering, and attenuation coefficients of ultrasound in phantoms with micro‐ and nanoparticles were estimated. Based on the attenuation and scattering of ultrasound in the samples, the ultrasonic energy absorption, which determines the heating efficiency, was evaluated. Additionally, the temperature increase during sonication of the phantoms by an ultrasonic beam was directly measured using thermocouples. Results The density of the materials with nanoparticles was higher than for the materials with microparticles with the same fractions of particles. The SOS for all materials ranged from 1489 to 1499 m/s. The attenuation in the whole frequency range (3–8 MHz) was higher for the materials with nanoparticles than for the materials with microparticles. For the materials with the lower content (8 mg/ml) of particles, the attenuation coefficient was 0.2 dB/(MHz cm). For the 16 mg/ml concentration of nanoparticles and microparticles, the attenuation coefficients were 0.66 and 0.45 dB/(MHz cm), respectively. The value of backscattering coefficient in the whole frequency range was greater for the materials with microparticles than for the materials with nanoparticles. The values of the integrated backscattering coefficient were 0.05 and 0.08 1/m for the materials with nanoparticles and 0.46 and 0.82 1/m for the materials with microparticles and concentrations of 8 and 16 mg/ml, respectively. The rates of temperature increase in the first 3 s due to ultrasonic heating were higher for the materials with nanoparticles than for the materials with microparticles. Conclusions Based on acoustical measurements, we confirmed that all materials can be used as tissue phantoms in the study of ultrasonic hyperthermia, as their properties were in the range of soft tissue properties. We found that the nanoparticle‐doped materials had greater attenuation and smaller scattering of ultrasound than the materials with microparticles,...

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Development and characterization of a tissue-mimicking material for high-intensity focused ultrasound

Cited by 55 publications

References 30 publications

5th International Symposium on Focused Ultrasound

5th International Symposium on Focused Ultrasound

Tissue mimicking materials for the detection of prostate cancer using shear wave elastography: A validation study

Ultrasound assessment of the conversion of sound energy into heat in tissue phantoms enriched with magnetic micro‐ and nanoparticles

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