An improved method to estimate ultrasonic absorption in agar-based gel phantom using thermocouples and MR thermometry

Drakos, Theocharis; Giannakou, Marinos; Menikou, Georgios; Ioannides, Cleanthis; Damianou, Christakis

doi:10.1016/j.ultras.2020.106089

Cited by 16 publications

(22 citation statements)

References 21 publications

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“…Although the scattering of the sample increased with the addition of silicon dioxide for an amount of over 4% w/v, the contribution of silicon dioxide to absorption significantly decreased. [ 25 ] Thereby, it seems that for a silicon dioxide concentration of more than 4% w/v, the attenuation is strongly affected by the decrement of absorption,[ 25 ] rather than the enhancement of the scattering phenomenon.…”

Section: Discussionmentioning

confidence: 99%

“…Figure 7 shows the attenuation coefficient versus the percentage of evaporated milk ( n = 10) for a preliminary agar and silicon dioxide concentration of 6% and 4%, respectively. The sample lost its stiffness with an evaporated milk percentage of over 30% as suggested in a previous study[ 25 ] and became too difficult to handle. Therefore, further investigation for higher evaporated milk concentrations was excluded.…”

Section: R Esultsmentioning

confidence: 97%

“…Although the increase of silicon dioxide concentration above 4% increased scattering, that scattering increment further lowered the ultrasonic absorption at a significant level as found in a previous study. [ 25 ] Although the scattering is expected to increase, the absorption which is the main factor of the attenuation significantly decreased and the total result led to an attenuation decrease. The attenuation decreases with increasing silicon dioxide concentration (over 4 %) possible due to the domination of the absorption decrease over the increase of scattering.…”

Section: R Esultsmentioning

confidence: 99%

“…In addition, silicon dioxide powder was added to control scattering independently, whereas evaporated milk served as a low scatter material that enhanced absorption. [ 25 ]…”

Section: Introductionmentioning

confidence: 99%

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Ultrasonic Attenuation of an Agar, Silicon Dioxide, and Evaporated Milk Gel Phantom

Drakos

Antoniou

Evripidou

et al. 2021

Journal of Medical Ultrasound

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Background: It has been demonstrated that agar-based gel phantoms can emulate the acoustic parameters of real tissues and are the most commonly used tissue-mimicking materials for high-intensity focused ultrasound applications. The following study presents ultrasonic attenuation measurements of agar-based phantoms with different concentrations of additives (percent of agar, silicon dioxide and evaporated milk) in an effort of matching the material's acoustic property as close as possible to human tissues. Methods: Nine different agar-based phantoms with various amounts of agar, silicon dioxide, and evaporated milk were prepared. Attenuation measurements of the samples were conducted using the through-transmission immersion techniques. Results: The ultrasonic attenuation coefficient of the agar-based phantoms varied in the range of 0.30–1.49 dB/cm-MHz. The attenuation was found to increase in proportion to the concentration of agar and evaporated milk. Silicon dioxide was found to significantly contribute to the attenuation coefficient up to 4% weight to volume (w/v) concentration. Conclusion: The acoustic attenuation coefficient of agar-based phantoms can be adjusted according to the tissue of interest in the range of animal and human tissues by the proper selection of agar, silicon dioxide, and evaporated milk.

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Section: Discussionmentioning

confidence: 99%

Section: R Esultsmentioning

confidence: 97%

Section: R Esultsmentioning

confidence: 99%

“…In addition, silicon dioxide powder was added to control scattering independently, whereas evaporated milk served as a low scatter material that enhanced absorption. [ 25 ]…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ultrasonic Attenuation of an Agar, Silicon Dioxide, and Evaporated Milk Gel Phantom

Drakos

Antoniou

Evripidou

et al. 2021

Journal of Medical Ultrasound

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“…Conventional ultrasonic imaging generates an average of 1000 pulses per second. Basic controlling principle of generator pulse is based on the amount of electric pulse used to change the intensity of ultrasonic scattering [8].…”

Section: Introductionmentioning

confidence: 99%

Carrageenan Biopolymer for Medical Ultrasonography using Phantom CIRS

Diartama¹,

Suryono

Sugiyanto

et al. 2020

E3S Web Conf.

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The use of polymer as conductor in medical ultrasonography is very crucial to establish patient diagnosis and to prevent administration of improper treatment. Rapid development in science and technology encourages people to create more innovations that are readily usable. However, these innovations sometimes put health and environmental aspects aside that in turn become disadvantageous to health and may lead to environmental pollution. This research proposes the use of carrageenan biopolymer as a safe alternative for people’s health and the environment. It aims to prove differences in resulting phantom CIRS images taken with the help of carrageenan gel and standard gel based on Carbomer 940 as acoustic coupling agents (ACA) for ultrasonography (USG). It is an experimental research that uses true experiment technique with posttest only control group design. Results from T-test analysis show significance value of p>0.05, meaning there is no significant difference between the use of carrageenan gel and ACA gel (Carbomer 940). This result proves that carrageenan gel can be used as an acoustic coupling agent for ultrasonography. Results from imaging tests also reveal that there is no difference between the use of carrageenan gel and that of a manufacturer gel based on Carbomer 940 available in Indonesia, in terms of visualization of phantom CIRS images.

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MR relaxation times of agar‐based tissue‐mimicking phantoms

Antoniou

Georgiou

Christodoulou

et al. 2022

J Applied Clin Med Phys

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Agar gels were previously proven capable of accurately replicating the acoustical and thermal properties of real tissue and widely used for the construction of tissue-mimicking phantoms (TMPs) for focused ultrasound (FUS) applications. Given the current popularity of magnetic resonance-guided FUS (MRgFUS), we have investigated the MR relaxation times T1 and T2 of different mixtures of agar-based phantoms. Nine TMPs were constructed containing agar as the gelling agent and various concentrations of silicon dioxide and evaporated milk. An agar-based phantom doped with wood powder was also evaluated. A series of MR images were acquired in a 1.5 T scanner for T1 and T2 mapping. T2 was predominantly affected by varying agar concentrations. A trend toward decreasing T1 with an increasing concentration of evaporated milk was observed. The addition of silicon dioxide decreased both relaxation times of pure agar gels.The proposed phantoms have great potential for use with the continuously emerging MRgFUS technology. The MR relaxation times of several body tissues can be mimicked by adjusting the concentration of ingredients, thus enabling more accurate and realistic MRgFUS studies.

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An improved method to estimate ultrasonic absorption in agar-based gel phantom using thermocouples and MR thermometry

Cited by 16 publications

References 21 publications

Ultrasonic Attenuation of an Agar, Silicon Dioxide, and Evaporated Milk Gel Phantom

Ultrasonic Attenuation of an Agar, Silicon Dioxide, and Evaporated Milk Gel Phantom

Carrageenan Biopolymer for Medical Ultrasonography using Phantom CIRS

MR relaxation times of agar‐based tissue‐mimicking phantoms

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