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Khodaverdi A, Cinthio M, Reistad E, Erlöv T, Malmsjö M, Zackrisson S, Reistad N. Optical tuning of copolymer-in-oil tissue-mimicking materials for multispectral photoacoustic imaging. Biomed Phys Eng Express 2024; 10:055009. [PMID: 38959869 DOI: 10.1088/2057-1976/ad5e85] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 07/03/2024] [Indexed: 07/05/2024]
Abstract
Objective. The availability of tissue-mimicking materials (TMMs) for manufacturing high-quality phantoms is crucial for standardization, evaluating novel quantitative approaches, and clinically translating new imaging modalities, such as photoacoustic imaging (PAI). Recently, a gel comprising the copolymer styrene-ethylene/butylene-styrene (SEBS) in mineral oil has shown significant potential as TMM due to its optical and acoustic properties akin to soft tissue. We propose using artists' oil-based inks dissolved and diluted in balsam turpentine to tune the optical properties.Approach. A TMM was fabricated by mixing a SEBS copolymer and mineral oil, supplemented with additives to tune its optical absorption and scattering properties independently. A systematic investigation of the tuning accuracies and relationships between concentrations of oil-based pigments and optical absorption properties of the TMM across visible and near-infrared wavelengths using collimated transmission spectroscopy was conducted. The photoacoustic spectrum of various oil-based inks was studied to analyze the effect of increasing concentration and depth.Main results. Artists' oil-based inks dissolved in turpentine proved effective as additives to tune the optical absorption properties of mineral oil SEBS-gel with high accuracy. The TMMs demonstrated long-term stability and suitability for producing phantoms with desired optical absorption properties for PAI studies.Significance. The findings, including tuning of optical absorption and spectral shape, suggest that this TMM facilitates the development of more sophisticated phantoms of arbitrary shapes. This approach holds promise for advancing the development of PAI, including investigation of the spectral coloring effect. In addition, it can potentially aid in the development and clinical translation of ultrasound optical tomography.
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Affiliation(s)
- Azin Khodaverdi
- Department of Biomedical Engineering, Lund University, 221 00 Lund, Sweden
| | - Magnus Cinthio
- Department of Biomedical Engineering, Lund University, 221 00 Lund, Sweden
| | | | - Tobias Erlöv
- Department of Biomedical Engineering, Lund University, 221 00 Lund, Sweden
| | - Malin Malmsjö
- Department of Clinical Sciences Lund, Ophthalmology, Skåne University Hospital, Lund University, 223 62 Lund, Sweden
| | - Sophia Zackrisson
- Department of Translational Medicine, Diagnostic Radiology, Lund University, 205 02 Malmö, Sweden
- Department of Medical Imaging and Physiology, Skåne University Hospital, 214 28 Malmö, Sweden
| | - Nina Reistad
- Department of Physics, Lund University, 221 00 Lund, Sweden
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Bühling B, Maack S, Strangfeld C. Fluidic Ultrasound Generation for Non-Destructive Testing. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2311724. [PMID: 38219043 DOI: 10.1002/adma.202311724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/04/2024] [Indexed: 01/15/2024]
Abstract
Air-coupled ultrasonic testing (ACU) is a pioneering technique in non-destructive testing (NDT). While contact testing and fluid immersion testing are standard methods in many applications, the adoption of ACU is progressing slowly, especially in the low ultrasonic frequency range. A main reason for this development is the difficulty of generating high amplitude ultrasonic bursts with equipment that is robust enough to be applied outside a laboratory environment. This paper presents the fluidic ultrasonic transducer as a solution to this challenge. This novel aeroacoustic source uses the flow instability of a sonic jet in a bistable fluidic switch to generate ultrasonic bursts up to 60 kHz with a mean peak pressure of 320 Pa. The robust design allows operation in adverse environments, independent of the operating fluid. Non-contact through-transmission experiments are conducted on four materials and compared with the results of conventional transducers. For the first time, it is shown that the novel fluidic ultrasonic transducer provides a suitable acoustic signal for NDT tasks and has potential of furthering the implementation of ACU in industrial applications.
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Affiliation(s)
- Benjamin Bühling
- Department 8 "Non-Destructive Testing", Bundesanstalt für Materialforschung und -prüfung, Unter den Eichen 87, 12205, Berlin, Germany
| | - Stefan Maack
- Department 8 "Non-Destructive Testing", Bundesanstalt für Materialforschung und -prüfung, Unter den Eichen 87, 12205, Berlin, Germany
| | - Christoph Strangfeld
- Department 8 "Non-Destructive Testing", Bundesanstalt für Materialforschung und -prüfung, Unter den Eichen 87, 12205, Berlin, Germany
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Frigo CA, Bellomo S, Bigatti M, Pellegrini R, Denza G, Di Stanislao E. A finite element analysis of load distribution during donning and orthostatic posture in the ITOP hybrid subischial socket. Prosthet Orthot Int 2023; 47:204-209. [PMID: 36701634 DOI: 10.1097/pxr.0000000000000209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 11/21/2022] [Indexed: 01/28/2023]
Abstract
INTRODUCTION Pressure and shear stresses applied to the stump of a transfemoral amputee wearing a newly designed prosthetic socket have been analyzed by a finite element modeling approach. METHODS The new socket was developed by the Istituto Tecnico Ortopedico Preneste, and it was named the "hybrid subischial socket." This work aimed at understanding the loads' distribution on the stump surface in 2 operative conditions: at the end of the wearing phase and during the orthostatic posture. The model of the stump was composed of 4 different materials: the femoral bone, the muscle tissue, the fat, and the skin layers. Except for the bone (rigid), the biological tissues were modeled as Neo-Hookean, and their mechanical properties were taken from the literature. The socket was composed of a containment frame, made of carbon fiber composite material, a shell made of flexible silicone, and a liner made of hyperelastic silicone. RESULTS The results of our simulation show that the main support areas are located in a proper position, in agreement with the ideal principles of this prosthetic design, and the maximum pressures are well below the pain threshold reported in the literature for the same contact areas. CONCLUSIONS We can conclude that although the upper rim of the socket is well below the ischiatic area, the new socket design allows for a safe and comfortable support of the body weight. This is in agreement with the evidence of a good functionality and acceptance of this prosthetics gathered in the many real applications.
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Affiliation(s)
- Carlo A Frigo
- Department of Electronics, Information and Bioengineering, Politenico di Milano, Milan, Italy
- Gait Analysis Lab, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | - Silvia Bellomo
- Department of Electronics, Information and Bioengineering, Politenico di Milano, Milan, Italy
| | - Matteo Bigatti
- Department of Electronics, Information and Bioengineering, Politenico di Milano, Milan, Italy
| | - Roberto Pellegrini
- ITOP SpA Officine Ortopediche, Prosthetics and Orthotics Clinic, Palestrina, Italy
| | - Gabriele Denza
- ITOP SpA Officine Ortopediche, Prosthetics and Orthotics Clinic, Palestrina, Italy
| | - Eugenio Di Stanislao
- ITOP SpA Officine Ortopediche, Prosthetics and Orthotics Clinic, Palestrina, Italy
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Sharma A, Marapureddy SG, Paul A, Bisht SR, Kakkar M, Thareja P, Mercado-Shekhar KP. Characterizing Viscoelastic Polyvinyl Alcohol Phantoms for Ultrasound Elastography. ULTRASOUND IN MEDICINE & BIOLOGY 2023; 49:497-511. [PMID: 36328889 DOI: 10.1016/j.ultrasmedbio.2022.09.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 09/22/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
Ultrasound phantoms mimic the acoustic and mechanical properties of native tissues. Polyvinyl alcohol (PVA) phantoms are used extensively as models for validating ultrasound elastography approaches. However, the viscous properties of PVA phantoms have not been investigated adequately. Glycerol is a viscous liquid that has been reported to increase the speed of sound of phantoms. This study aims to assess the acoustic and viscoelastic properties of PVA phantoms and PVA mixed with glycerol at varying concentrations. The phantoms were fabricated with 10% w/v PVA in water with varying concentrations of glycerol (10%, 15% and 20% v/v) and 2% w/v silicon carbide particles as acoustic scatterers. The phantoms were subjected to either one, two, or three 24-h freeze-thaw cycles. The longitudinal sound speeds of all PVA phantoms were measured, and ranged from 1529 to 1660 m/s. Attenuation spectroscopy was performed in the range of 5 to 20 MHz. The measured attenuation followed a power-law relationship with frequency, wherein the power-law fit constants and exponents ranged from 0.02 to 0.1 dB/cm/MHzn and from 1.6 to 1.9, respectively. These results were in agreement with previous reports for soft tissues. Viscoelasticity of PVA phantoms was assessed using rheometry. The estimated values of shear modulus and viscosity using the Kelvin-Voigt and Kelvin-Voigt fractional derivative models were within the range of previously-reported tissue-mimicking phantoms and soft tissues. The number of freeze-thaw cycles were shown to alter the viscosity of PVA phantoms, even in the absence of glycerol. Scanning electron microscopy images of PVA phantoms without glycerol showed a porous hydrogel network, in contrast to those of PVA-glycerol phantoms with non-porous structure. Phantoms fabricated in this study possess tunable acoustic and viscoelastic properties within the range reported for healthy and diseased soft tissues. This study demonstrates that PVA phantoms can be manufactured with glycerol for applications in ultrasound elastography.
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Affiliation(s)
- Ananya Sharma
- Discipline of Biological Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat, India
| | - Sai Geetha Marapureddy
- Discipline of Chemical Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat, India
| | - Abhijit Paul
- Discipline of Biological Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat, India
| | - Sapna R Bisht
- Discipline of Biological Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat, India
| | - Manik Kakkar
- Discipline of Electrical Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat, India
| | - Prachi Thareja
- Discipline of Chemical Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat, India
| | - Karla P Mercado-Shekhar
- Discipline of Biological Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat, India.
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Stiles TA. Phantoms for Quantitative Ultrasound. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1403:281-301. [PMID: 37495923 DOI: 10.1007/978-3-031-21987-0_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
Tissue-mimicking materials and phantoms have an important role in quantitative ultrasound. These materials allow for investigation of new techniques with the ability to design materials with properties that are stable over time and available for repeated measurements to refine techniques and analysis algorithms. This chapter presents an overview of the history of phantoms, methods of creation of materials with a variety of acoustic properties, and methods of measurement of those properties. It includes a section addressing the measurement of variance in those techniques using interlaboratory comparisons. There is a wide range of existing tissue-mimicking materials that exhibit properties similar to those of most soft tissues. Ongoing work is part of the expansion of QUS as materials are developed to better mimic specific tissues, geometries, or pathologies.
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Cabrelli LC, Uliana JH, da Cruz Junior LB, Bachmann L, Carneiro AAO, Pavan TZ. Glycerol-in-SEBS gel as a material to manufacture stable wall-less vascular phantom for ultrasound and photoacoustic imaging. Biomed Phys Eng Express 2021; 7. [PMID: 34496358 DOI: 10.1088/2057-1976/ac24d6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/08/2021] [Indexed: 11/12/2022]
Abstract
Styrene-ethylene/butylene-styrene (SEBS) copolymer-in-mineral oil gel is an appropriate tissue-mimicking material to manufacture stable phantoms for ultrasound and photoacoustic imaging. Glycerol dispersion has been proposed to further tune the acoustic properties and to incorporate hydrophilic additives into SEBS gel. However, this type of material has not been investigated to produce wall-less vascular flow phantom for these imaging modalities. In this paper, the development of a wall-less vascular phantom for ultrasound and photoacoustic imaging is reported. Mixtures of glycerol/TiO2-in-SEBS gel samples were manufactured at different proportions of glycerol (10%, 15%, and 20%) and TiO2(0% to 0.5%) to characterize their optical and acoustic properties. Optical absorption in the 500-950 nm range was independent of the amount of glycerol and TiO2, while optical scattering increased linearly with the concentration of TiO2. Acoustic attenuation and speed of sound were not influenced by the presence of TiO2. The sample manufactured using weight percentages of 10% SEBS, 15% glycerol, and 0.2% TiO2was selected to make the vascular phantom. The phantom proved to be stable during the pulsatile blood-mimicking fluid (BMF) flow, without any observed damage to its structure or leaks. Ultrasound color Doppler images showed a typical laminar flow, while the B-mode images showed a homogeneous speckled pattern due to the presence of the glycerol droplets in the gel. The photoacoustic images of the phantom showed a well-defined signal coming from the surface of the phantom and from the vessels where BMF was flowing. The Spearman's correlations between the photoacoustic and tabulated spectra calculated from the regions containing BMF, in this case a mixture of salt solutions (NiCl2and CuSO4), were higher than 0.95. Our results demonstrated that glycerol-in-SEBS gel was an adequate material to make a stable vascular flow phantom for ultrasound photoacoustic imaging.
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Affiliation(s)
- Luciana C Cabrelli
- Departamento de Física, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Joao H Uliana
- Departamento de Física, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
| | | | - Luciano Bachmann
- Departamento de Física, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Antonio A O Carneiro
- Departamento de Física, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Theo Z Pavan
- Departamento de Física, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
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Abstract
The ultrasound phantoms used to educate medical students should not only closely mimic the ultrasound characteristics of human soft tissues but also be inexpensive and easy to manufacture. I have been studying handmade ultrasound phantoms and proposed an ultrasound phantom comprising calcium alginate hydrogel that met these requirements but caused a speckle pattern similar to that observed in ultrasound images of liver. In this study, I show that adding ethanol to the precursors used to fabricate the phantom reduces the speckle pattern. The ultrasound propagation velocity and attenuation coefficient of the phantom were 1561 ± 8 m/s and 0.54 ± 0.18 dB/cm/MHz, respectively (mean ± standard deviation), which are within the ranges of those in human soft tissues (1530-1600 m/s and 0.3-1.0 dB/cm/MHz, respectively). This phantom is easy to fabricate without special equipment, is inexpensive, and is suitable for elementary training on ultrasound diagnosis, operation of ultrasound-guided needles, and blind catheter insertion.
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Affiliation(s)
- Minoru Aoyagi
- Department of Electrical and Electronics Engineering, Nippon Institute of Technology, Miyashiro, Saitama, Japan
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Pavan TZ, Evertsson M. Oil-Based Gel Phantoms and the Speed of Sound. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:3170-3171. [PMID: 32782089 DOI: 10.1016/j.ultrasmedbio.2020.07.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/07/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Affiliation(s)
- Theo Z Pavan
- Department of Physics, FFCLRP, University of São Paulo, Ribeirão Preto, SP, Brazil.
| | - Maria Evertsson
- Biomedical Engineering, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
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Alves N, Courtney BK. Response to "Oil-Based Gel Phantoms and the Speed of Sound". ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:3172. [PMID: 32807569 DOI: 10.1016/j.ultrasmedbio.2020.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 07/14/2020] [Indexed: 06/11/2023]
Affiliation(s)
- Natasha Alves
- Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Brian K Courtney
- Sunnybrook Research Institute, Toronto, Ontario, Canada; Department of Cardiology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Conavi Medical, North York, Ontario, Canada.
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