Liquid or Solid Ultrasonically Tissue-Mimicking Materials with Very Low Scatter (original) (raw)
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A Review of Tissue Substitutes for Ultrasound Imaging
Ultrasound in Medicine and Biology, 2010
The characterization and calibration of ultrasound imaging systems requires tissue-mimicking phantoms with known acoustic properties, dimensions and internal features. Tissue phantoms are available commercially for a range of medical applications. However, commercial phantoms may not be suitable in ultrasound system design or for evaluation of novel imaging techniques. It is often desirable to have the ability to tailor acoustic properties and phantom configurations for specific applications. A multitude of tissue-mimicking materials and phantoms are described in the literature that have been created using a variety of materials and preparation techniques and that have modeled a range of biological systems. This paper reviews ultrasound tissue-mimicking materials and phantom fabrication techniques that have been developed over the past four decades, and describes the benefits and disadvantages of the processes. Both soft tissue and hard tissue substitutes are explored. (E-mail: mculjat@mednet.ucla.edu)
Novel tissue mimicking materials for high frequency breast ultrasound phantoms
Ultrasound in Medicine & Biology, 2011
The development and acoustical characterisation of a range of novel agar-based tissue mimicking material (TMMs) for use in clinically relevant, quality assurance (QA) and anthropomorphic breast phantoms are presented. The novel agar-based TMMs described in this study are based on a comprehensive, systematic variation of the ingredients in the International Electrotechnical Commission (IEC) TMM. A novel, solid fat-mimicking material was also developed and acoustically characterised. Acoustical characterisation was carried out using an in-house scanning acoustic macroscope at low (7.5 MHz) and high frequencies (20 MHz), using the pulse-echo insertion technique. The speeds of sound range from 1490 to 1570 m. s -1 , attenuation coefficients range from 0.1 to 0.9 dB. cm -1 . MHz -1 and relative backscatter ranges from 0 to -20 dB. It was determined that tissues can be mimicked in terms of independently controllable speeds of sound and attenuation coefficients. These properties make these novel TMMs suitable for use in clinically relevant QA and anthropomorphic phantoms, and would potentially be useful for other high frequency applications such as intra-vascular and small animal imaging.
Ultrasonic Imaging, 2012
Backscatter and attenuation coefficient estimates are needed in many quantitative ultrasound strategies. In clinical applications, these parameters may not be easily obtained because of variations in scattering by tissues overlying a region of interest (ROI). The goal of this study is to assess the accuracy of backscatter and attenuation estimates for regions distal to nonuniform layers of tissue-mimicking materials. In addition, this work compares results of these estimates for "layered" phantoms scanned using different clinical ultrasound machines. Two tissue-mimicking phantoms were constructed, each exhibiting depth-dependent variations in attenuation or backscatter. The phantoms were scanned with three ultrasound imaging systems, acquiring radio frequency echo data for offline analysis. The attenuation coefficient and the backscatter coefficient (BSC) for sections of the phantoms were estimated using the reference phantom method. Properties of each layer were also measured with laboratory techniques on test samples manufactured during the construction of the phantom. Estimates of the attenuation coefficient versus frequency slope, α0, using backscatter data from the different systems agreed to within 0.24 dB/cm-MHz. Bias in the α0 estimates varied with the location of the ROI. BSC estimates for phantom sections whose locations ranged from 0 to 7 cm from the transducer agreed among the different systems and with theoretical predictions, with a mean bias error of 1.01 dB over the used bandwidths. This study demonstrates that attenuation and BSCs can be accurately estimated in layered inhomogeneous media using pulse-echo data from clinical imaging systems.
2012
In medical ultrasound, the backscatter coefficient is used to quantify the scattering properties of biological tissues. It is defined as the differential scattering cross section per unit volume for a scattering angle of 180°. In this study, measurements of the backscatter coefficient are made on Tissues Mimicking Materials (TMM). These are materials the acoustic properties of which (velocity propagation, attenuation, scattering) are close to those of biological tissues. Measurements of this coefficient have been achieved on a mixture of gelatin and distilled water containing graphite particles of mean radius 18 µm, which were randomly distributed. TMM samples with graphite concentrations ranging from 50 to 200 g per liter of gelatin have been investigated. The backscatter coefficient was evaluated using both Sigelman and Reid [JASA 53, 1351 (1973)] and Chen [IEEE Trans. UFFC 44, 515 (1997)] methods in a frequency range around 5 MHz. The evolution of this coefficient as a function o...
Development of tissue-equivalent phantoms for biomedical ultrasonic applications
International Journal of Biomedical Engineering and Technology, 2008
Tissue phantoms are, generally, used in the calibration of therapeutic and diagnostic systems. Thus, Tissue-Mimicking (TM) phantoms are developed and studied here for various ultrasonic output parameters. These phantoms have been developed by using agar-based Tissue-Mimicking Materials (TMM) with alumina as an absorption material. A pulser-receiver (make Panametrics, Model-5800, Waltham, MA 02154, USA) has been used to measure ultrasonic velocity and attenuation coefficient, which were found to be 1540-1550 m/s and attenuation 10.0-35.0 dB/m-MHz at frequencies from 2.5 MHz to 5.0 MHz. These ultrasound test phantoms incorporating TM material are useful in the performance evaluation of medical ultrasound systems.
Ultrasound phantom with solids mimicking cancerous tissue for needle breast biopsy
Turkish Journal of Chemistry, 2022
Introduction Breast cancer is the most frequent type of cancer among women in the world and constitutes 30% of all types of cancer observed in women [1]. According to the data in the year 2009, one of every four women has breast cancer and it is 24.1% of all cancer types. Although there are improvements in the medical sciences, development of early detection methods, and increased sensitiveness of the public, breast cancer continues to threaten life. Another step to decrease this threat is to increase the number and experience of specialized personnel and also of research opportunities. Therefore, this study aims to synthesize and characterize hydrogels and, design a phantom used to determine cancerous tissues by biopsy along with ultrasonography. Training phantoms, simulating every part of the human body, are developed by diagnostic, X-ray, multiple modeling, mammography, radiation therapy, and ultrasound methods [2] which developed since 1960 [3]. Training phantoms are released by global firms such as Kyoto Kagaku (ABDFAN®-about 9500$) and CIRS (Zerdine®-about 3000$) [4]. Repeated use of phantoms caused needle tracks, which were a problem, and solved with patented material, zerdine. However, commercial phantoms are expensive and hard to prepare, therefore there are a lot of studies to design alternative noncommercial, lowcost phantoms. For the materials which will be used to simulate breast tissue (BT), the average velocity of sound should be 1540 m/s for better ultrasonographic performances [5]. In this study, the acoustic properties of PAAm hydrogels as a tissue material were investigated by designing a test phantom for ultrasonography. The most popular materials reported in the literature for phantom design, are agar [6], graphite [7], polyurethane foam [8], magnesium silicate gels [9], SiC powder [10], natural gelatin [11], polyacrylamide gel [12], polyurethane [13], polyvinyl alcohol [14], thickened milk [15], urethane rubber [15], and cornstarch in gelatin suspension [16]. In another study, it is reported a phantom that was made by using gelatin and psyllium [17]. In another study, they used grapes or gloves filled with water as tumorous tissue and solid particles like macaroni, carrot pieces, or olives. Xu et al. [18] designed a phantom as tendon placed in swine muscle and biopsy showed less needle marks than gelatin-based phantoms after
Development of a Tissue-Mimicking Phantom of the Brain for Ultrasonic Studies
Ultrasound in Medicine & Biology, 2018
Constructing tissue-mimicking phantoms of the brain for ultrasonic studies is complicated by the low backscatter coefficient of brain tissue, causing difficulties in simultaneously matching the backscatter and attenuation properties. In this work, we report on the development of a polyvinyl alcohol-based tissue-mimicking phantom with properties approaching those of human brain tissue. Polyvinyl alcohol was selected as the base material for the phantom as its properties can be varied by freezeÀthaw cycling, variations in concentration and the addition of scattering inclusions, allowing some independent control of backscatter and attenuation. The ultrasonic properties (including speed of sound, attenuation and backscatter) were optimized using these methods with talc powder as an additive. It was determined that the ultrasonic properties of the phantom produced in this study are best matched to brain tissue in the frequency range 1À3 MHz, indicating its utility for laboratory ultrasonic studies in this frequency range.
Oil-in-gelatin dispersions for use as ultrasonically tissue-mimicking materials
Ultrasound in Medicine & Biology, 1982
Abstraet--A form of tissue-mimicking material is reported in which oil droplets are dispersed in a water-based gelatin. Broad ranges of ultrasonic parameters, including speed of sound, attenuation coefficient, density and backscatter level, exist for this material. Very important, the attenuation coefficients are nearly proportional to the frequency as in the case of mammalian tissue and the available attenuation coefficient slopes span the range of mammalian tissues. The available range of slopes is 0.1 dB/cm/MHz through at least 2.0 dB/cm/MHz. The available speeds of sound range from a minimum below that of mammalian fat (-1460 m/s) to a maximum above the accepted average for human tissue (1540 m/s). Densities available range from below that of fat (-0.92 gm/cm 3) through about 1.00gm/cm 3. Backscatter levels are easily made negligible compared to clinical levels and compared to those exhibited in previously reported tissue-mimicking materials in which the suspended particles are solid . Addition of solid or hollow glass scatterers allows backscatter levels to be made comparable to those clinically observed.
Journal of Medical Ultrasound, 2018
Since the 1960s, tissue-mimicking material (TMM) has been utilized for the preparation and characterization of ultrasound imaging. Wall-less flow phantoms are as well utilized to examine the performance of ultrasound device for practicing of sonographers. The achievement of equivalent TMM is a necessary to process for a quality monitor of Doppler ultrasound diagnostic instrument. It is essential that chemical items utilized in the TMM are prepared in a planned method to be nearly equal to the acoustical properties of real tissue with attenuation and speed of sound of 1540 ± 30 m/s, <0.5 dB/cm at MHz, respectively. [1-3] Flow phantom is a model of TMM with a vessel-mimicking material (VMM) surrounding it during pumping of blood-mimicking fluid (BMF). [4-7] The acoustical features of the different ingredients of the flow phantom correspond to the acoustical features of human blood, tissue, and vessel. [8] As required and identified by the International Electrotechnical Commission (IEC 61685 standard 1999), [10] it can be applied for a proper BMF and TMM. [10-12] However, when the tubing materials are lacking acoustic properties, the deformation of the Doppler spectrum will lead to the refraction at the vessel wall [13,14] and attenuation. [15,16] Regarding acoustical and physical properties, the most proper tubing materials are known as C-flex™. The acoustic speed in the tube should be identical (the same ranges to the TMM) to prevent refraction artifacts. [17] The speed of sound in TMM is usually 1540 m/s. [17-20] The refraction artifacts can be noticed when using tubes with a high velocity of sound. [21] Several researchers [17,19,22-30] have measured and examined both the acoustic speed and attenuation of the tube (TMM) by pulse echo signal technique. Through comprehensive literature review, the studies measured and calculated the speed of sound and attenuation through the solid (TMM) samples via measuring the time of flight (ToF) or time shift, t, of the signal