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A Cost-Effective Reusable Tissue Mimicking Phantom for High Intensity Focused Ultrasonic Liver Surgery. BIOENGINEERING (BASEL, SWITZERLAND) 2022; 9:bioengineering9120786. [PMID: 36550992 PMCID: PMC9774244 DOI: 10.3390/bioengineering9120786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/24/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022]
Abstract
A polyacrylamide polysaccharide hydrogel (PASG) containing a nonionic surfactant of the polyoxyethylene nonylphenyl ethers series (NP14) has been adapted to the fabrication of a reusable cost-effective ultrasonic tissue-mimicking phantom for real-time visualization of the thermal lesions by high intensity focused ultrasound (HIFU) irradiation. The constructed NP14 (40% in w/v) PASG is optically transparent at room temperatures, and it turns out to be opaque white as heated over the clouding points of about 55 °C and returns to its original transparent state after cooling. The acoustic property of the proposed phantom is similar to those of human liver tissues, which includes the acoustic impedance of 1.68 Mrayls, the speed of sound of 1595 ± 5 m/s, the attenuation coefficient of 0.52 ± 0.05 dB cm-1 (at 1 MHz), the backscatter coefficient of 0.21 ± 0.09 × 10-3 sr-1 cm-1 (at 1 MHz), and the nonlinear parameter B/A of 6.4 ± 0.2. The NP14-PASG was tested to assess the characteristic information (sizes, shapes, and locations) of the thermal lesions visualized when exposed to typical HIFU fields (1.1 MHz, focal pressure up to 20.1 MPa, focal intensity 4075 W/cm2). The proposed NP14-PASG is expected to replace the existing costly BSA-PASG used for more effective testing of the performance of therapeutic ultrasonic devices based on thermal mechanisms.
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Zhong X, Cao Y, Zhou P. Thermochromic Tissue-Mimicking Phantoms for Thermal Ablation Based on Polyacrylamide Gel. ULTRASOUND IN MEDICINE & BIOLOGY 2022; 48:1361-1372. [PMID: 35623921 DOI: 10.1016/j.ultrasmedbio.2022.03.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 06/15/2023]
Abstract
In recent years, thermal ablation has played an increasingly important role in treating various tumors in the clinic. A practical thermochromic phantom model can provide a favorable platform for clinical thermotherapy training of young physicians or calibration and optimization of thermal devices without risk to animals or human participants. To date, many tissue-mimicking thermal phantoms have been developed and are well liked, especially the polyacrylamide gel (PAG)-based phantoms. This review summarizes the PAG-based phantoms in the field of thermotherapy, details their advantages and disadvantages and provides a direction for further optimization. The relevant physical parameters (such as electrical, acoustic, and thermal properties) of these phantoms are also presented in this review, which can assist operators in a deeper understanding of these phantoms and selection of the proper recipes for phantom fabrication.
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Affiliation(s)
- Xinyu Zhong
- Department of Ultrasound, Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yuting Cao
- Institute of Ultrasound Imaging & Department of Ultrasound, Second Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ultrasound Molecular Imaging, Chongqing, China
| | - Ping Zhou
- Department of Ultrasound, Third Xiangya Hospital, Central South University, Changsha, Hunan, China.
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Zhong X, Zhou P, Zhao Y, Liu W, Zhang X. A novel tissue-mimicking phantom for US/CT/MR-guided tumor puncture and thermal ablation. Int J Hyperthermia 2022; 39:557-563. [PMID: 35379066 DOI: 10.1080/02656736.2022.2056249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
AIM This study aimed to develop a novel tumor-bearing tissue phantom model that can be used for US/CT/MR-guided tumor puncture and thermal ablation. METHODS The phantom model comprised two parts: a normal tissue-mimicking phantom and a tumor-mimicking phantom. A normal tissue phantom was prepared based on a polyacrylamide gel mixed with thermochromic ink. Moreover, a spherical phantom containing contrast agents was constructed and embedded in the tissue phantom to mimic a tumor lesion. US/CT/MR imaging features and thermochromic property of the phantom model were characterized. Finally, the utility of the phantom model for imaging-guided microwave ablation training was examined. RESULTS The tumor phantom containing contrast agents showed hyper-echogenicity, higher CT numbers, and lower T2 signal intensity compared with the normal tissue phantom in US/CT/MR images. Consequently, we could locate the position of the tumor in US/CT/MR imaging and perform an imaging-guided tumor puncture. When the temperature reached the threshold of 60 °C, the phantom exhibited a permanent color change from cream white to magenta. Based on this obvious color change, our phantom model could clearly map the thermal ablation region after thermotherapy. CONCLUSIONS We developed a novel US/CT/MR-imageable tumor-bearing tissue model that can be used for imaging-guided tumor puncture and thermal ablation. Furthermore, it allows visual assessment of the ablation region by analyzing the obvious color change. Overall, this phantom model could be a good training tool in the field of thermal ablation.
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Affiliation(s)
- Xinyu Zhong
- Department of Ultrasound, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Ping Zhou
- Department of Ultrasound, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Yongfeng Zhao
- Department of Ultrasound, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Wengang Liu
- Department of Ultrasound, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Xinghao Zhang
- Department of Ultrasound, The Third Xiangya Hospital, Central South University, Changsha, China
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Sun D, Liu J, Xue L, Li L, Xie D, Li S, Li S, Wang X, Yin D, Ren Z, Bai R, Guo W, Liu Y, Chen C. A solid ultrasonic coupling membrane for superficial vascular ultrasonography. NANOSCALE 2022; 14:3545-3553. [PMID: 35174834 DOI: 10.1039/d1nr05353a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Superficial thrombophlebitis is one of the most significant complications of superficial vein thrombosis. Rapid imaging and mapping with high resolution is particularly important for accurate diagnosis so as to carry out treatment as soon as possible. Ultrasound imaging technology has been used extensively because of the low-cost, minimal invasiveness, and convenient application in clinical practice. And the ultrasonic couplant is an essential component in ultrasound examination. However, when imaging superficial structures, traditional liquid ultrasonic couplants often produce inadequate results. In this study, we investigate whether a hydrogel membrane can be used to improve the imaging of superficial vessels. To this end, we generated a polyacrylamide-bacterial nanocellulose hydrogel membrane (PAM-BC) that efficiently forms at 60 °C in only 10 min by redox polymerization. With PAM-BC-2.5, it was possible to acquire high resolution intravascular ultrasound images to assess superficial vessels in humans and the superficial vasculature in rats and miniature pigs using various brands of ultrasound instruments. The PAM-BCs represent a new, solid ultrasonic membrane which is suitable for diagnosing disease in superficial vessels.
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Affiliation(s)
- Di Sun
- GBA National Institute for Nanotechnology Innovation, Guangzhou, Guangdong 510700, P.R. China.
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100190, P.R. China.
| | - Jie Liu
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing 100853, P.R. China.
| | - Lijuan Xue
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing 100853, P.R. China.
| | - Li Li
- Department of Ultrasound, Hospital of Renmin University of China, Beijing 100872, P.R. China
| | - Daoyin Xie
- Department of Echocardiography, Peking University Third Hospital, Beijing 100191, P.R. China
| | - Shilin Li
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100190, P.R. China.
| | - Shengmei Li
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100190, P.R. China.
| | - Xinlian Wang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100190, P.R. China.
| | - Dongtao Yin
- PLA Rocket Force Characteristics Medical Center, Beijing 100888, P.R. China
| | - Zhaoqi Ren
- PLA Rocket Force Characteristics Medical Center, Beijing 100888, P.R. China
| | - Ru Bai
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100190, P.R. China.
| | - Wei Guo
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing 100853, P.R. China.
| | - Ying Liu
- GBA National Institute for Nanotechnology Innovation, Guangzhou, Guangdong 510700, P.R. China.
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100190, P.R. China.
| | - Chunying Chen
- GBA National Institute for Nanotechnology Innovation, Guangzhou, Guangdong 510700, P.R. China.
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100190, P.R. China.
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Morchi L, Gini M, Mariani A, Pagliarani N, Cafarelli A, Tognarelli S, Menciassi A. A Reusable Thermochromic Phantom for Testing High Intensity Focused Ultrasound Technologies. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021; 2021:1431-1434. [PMID: 34891554 DOI: 10.1109/embc46164.2021.9629845] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
High Intensity Focused Ultrasound (HIFU) surgery is a promising technology for the treatment of several pathologies, including cancer. Testing is a fundamental step for verifying treatment efficacy and safety. Ex-vivo tissues represent the most common solution for replicating the properties of human tissues in the HIFU operative scenario. However, they constitute an avoidable waste of resources. Thus, tissue mimicking phantoms have been investigated as a more sustainable and reliable alternative. In this scenario, we proposed a reusable silicone-based thermochromic phantom. It is cost-effective and can be rapidly fabricated. The acoustic, mechanical, and thermal characterization of the phantom are reported. The phantom usability was evaluated with a HIFU robotic platform. 18 different working conditions were tested by varying both sonication power and duration. Temperature and simulated lesions' size were quantified for all testing conditions. An accordance between temperature and lesion dimension trend over time was found. The proposed phantom results a valid alternative to ex-vivo tissues, especially in the early stages of developing novel HIFU treatment paradigms.
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Antoniou A, Evripidou N, Giannakou M, Constantinides G, Damianou C. Acoustical properties of 3D printed thermoplastics. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 149:2854. [PMID: 33940906 DOI: 10.1121/10.0004772] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 04/03/2021] [Indexed: 06/12/2023]
Abstract
With focused ultrasound (FUS) gaining popularity as a therapeutic modality for brain diseases, the need for skull phantoms that are suitable for evaluating FUS protocols is increasing. In the current study, the acoustical properties of several three-dimensional (3D) printed thermoplastic samples were evaluated to assess their suitability to mimic human skull and bone accurately. Samples were 3D printed using eight commercially available thermoplastic materials. The acoustic properties of the printed samples, including attenuation coefficient, speed of sound, and acoustic impedance, were investigated using transmission-through and pulse-echo techniques. The ultrasonic attenuation, estimated at a frequency of 1.1 MHz, varied from approximately 7 to 32 dB/cm. The frequency dependence of attenuation was described by a power law in the frequency range of 0.2-3.5 MHz, and the exponential index of frequency was found to vary from 1.30 to 2.24. The longitudinal velocity of 2.7 MHz sound waves was in the range of 1700-3050 m/s. The results demonstrate that thermoplastics could potentially be used for the 3D construction of high-quality skull phantoms.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering and Computer Engineering and Informatics, Cyprus University of Technology, 30 Archiepiskopou Kyprianou Street, Limassol, 3036, Cyprus
| | - Nikolas Evripidou
- Department of Electrical Engineering and Computer Engineering and Informatics, Cyprus University of Technology, 30 Archiepiskopou Kyprianou Street, Limassol, 3036, Cyprus
| | - Marinos Giannakou
- MEDSONIC LTD, 35 Christaki Kranou Street, Germasogia, Limassol, 4041, Cyprus
| | - Georgios Constantinides
- Department of Mechanical Engineering and Materials Science and Engineering, Cyprus University of Technology, 30 Archiepiskopou Kyprianou Street, Limassol, 3036, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering and Computer Engineering and Informatics, Cyprus University of Technology, 30 Archiepiskopou Kyprianou Street, Limassol, 3036, Cyprus
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Boppudi ST, Belal S, Guntur SR. Preparation and characterization of a novel sprayable hydrogel for skin preparation to record ECG and other biopotentials. Biomed Eng Lett 2020; 10:533-546. [PMID: 33194246 DOI: 10.1007/s13534-020-00164-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 06/30/2020] [Accepted: 07/20/2020] [Indexed: 10/23/2022] Open
Abstract
Wet electrodes are widely used to perform biopotential measurements from the body, such as electroencephalogram, electrocardiogram, and electromyogram. These electrodes have certain disadvantages, including bacterial growth, irritation in long-term recordings, infection to patients' skin caused by skin preparation techniques, and unpleasant feeling caused after their removal. Thus, a sprayable hydrogel (SH) was designed to avoid these problems. Five electrode configurations, namely, Zipprep™, wet Ag/AgCl, wipes, dry Ag/AgCl, and SH, were tested using an impedance analyzer. Measurements were obtained by placing each of the electrode systems on the forearm of five subjects, which comprised one Caucasian, two Indians, one Syrian, and one Cypriot aging between 23 and 60 years for 10 min. Impedance versus time and reactance versus resistance performance plots were compared and assessed. The performance of the SH sprayed under dry electrodes had lower impedance values compared with those of the dry Ag/AgCl and wipes. As a result, the SH electrode configuration can be used as an electrode set-up for acquiring and recording various physiological signals.
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Affiliation(s)
- Sunil Tej Boppudi
- Department of Biomedical Engineering, Vignan's Foundation for Science, Technology and Research, Vadlamudi, Guntur, 522213 India.,Department of Electronics and Communications Engineering, Vignan's Foundation for Science, Technology and Research, Vadlamudi, Guntur, 522213 India
| | - Suliman Belal
- School of Biological Sciences, Division of Neuroscience and Experimental Psychology, Manchester University, Zochonis Building, Brunswick Street, Manchester, M13 9PT UK
| | - Sitaramanjaneya Reddy Guntur
- Department of Biomedical Engineering, Vignan's Foundation for Science, Technology and Research, Vadlamudi, Guntur, 522213 India.,Department of Electronics and Communications Engineering, Vignan's Foundation for Science, Technology and Research, Vadlamudi, Guntur, 522213 India
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Hydrogels Obtained via γ-Irradiation Based on Poly(Acrylic Acid) and Its Copolymers with 2-Hydroxyethyl Methacrylate. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10144960] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hydrogels containing both carboxyl and hydroxyl functional groups have been prepared by γ-irradiation of either aqueous solutions of acrylic acid (AA) and mixtures of AA and 2-hydroxyethyl methacrylate (HEMA) in different ratios, or aqueous solutions of poly(AA), PAA, and poly(AA-co-HEMA) obtained via solution polymerization. A higher absorbed dose is required in order to prepare hydrogels from monomer solutions, compared with those from polymer solutions. The range for the absorbed doses was chosen so that the probability of crosslinking reactions is higher than that of degradation ones. As the radiation energy deposited in a sample increases, the equilibrium swelling degree and the average molar mass between crosslinks diminishes. Chemical transformations induced by radiation were investigated by means of FTIR spectroscopy and thermal analysis of polymers before and after irradiation. For all these systems, the formation of a three-dimensional network enhances the glass transition temperature and thermal stability, but a further increase in the crosslinking degree may have the reverse effect on the glass transition temperature. Depending on the preparation protocol and/or hydrogel composition, superabsorbent materials that can bind different compounds throughout side functional groups may be obtained.
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Guntur SR, Choi MJ. Temperature Dependence of Tissue Thermal Parameters Should Be Considered in the Thermal Lesion Prediction in High-Intensity Focused Ultrasound Surgery. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:1001-1014. [PMID: 31983483 DOI: 10.1016/j.ultrasmedbio.2019.10.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 10/21/2019] [Accepted: 10/26/2019] [Indexed: 06/10/2023]
Abstract
This study considers the temperature-dependent thermal parameters (specific heat capacity, thermal diffusivity and thermal conductivity) used when predicting the temperature rise of tissue exposed to high-intensity focused ultrasound (HIFU). Numerical analysis was performed using the Khokhlov-Zabolotskaya-Kuznetsov equation coupled with a bioheat transfer function. The thermal parameters were set as the functions of temperature using experimental data. The results revealed that, for liver tissue exposed to HIFU with a focal intensity of 3000 W/cm2 for 10 s, the predicted focal temperature rise was 23% lower and the thermal lesion area 41% smaller than those predicted without considering the temperature dependence. The prediction was validated by experimental observations on thermal lesions visualized in a tissue-mimicking phantom. The present results suggest that temperature-dependent thermal parameters should be considered in the prediction of HIFU-induced temperature rise to avoid lowering ultrasonic output settings for HIFU surgery. The aim of the present study was to investigate how significantly the temperature dependence of the thermal parameters affects the thermal dose imposed on the tissue by a typical clinical HIFU device. A numerical simulation was performed using a thermo-acoustic algorithm coupling the non-linear Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation (Meaney et al. 1998; Filonenko and Khokhlova 2001) and a bio-heat transfer (BHT) equation (Pennes 1948). Thermal parameters of liver tissue were modeled in the present study as functions of temperature and were incorporated into the BHT equation to compensate for the variations in thermal parameters with temperature. Experimental validation was achieved by comparing the predictions with the thermal lesions formed in the tissue-mimicking phantoms.
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Affiliation(s)
- Sitaramanjaneya Reddy Guntur
- Department of Biomedical Engineering, Vignan's Foundation for Science, Technology and Research, Vadlamudi, Guntur, India
| | - Min Joo Choi
- Department of Medicine, School of Medicine, Jeju National University, Jeju, Republic of Korea.
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Iwahashi T, Tang T, Matsui K, Fujiwara K, Itani K, Yoshinaka K, Azuma T, Takagi S, Sakuma I. Visualization of Temperature Distribution around Focal Area and Near Fields of High Intensity Focused Ultrasound Using a 3D Measurement System. ADVANCED BIOMEDICAL ENGINEERING 2018. [DOI: 10.14326/abe.7.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
| | | | | | | | | | - Kiyoshi Yoshinaka
- Health Research Institute, National Institute of Advanced Industrial Science and Technology
| | | | - Shu Takagi
- Department of Engineering, University of Tokyo
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Manaspon C, Hernandez C, Nittayacharn P, Jeganathan S, Nasongkla N, Exner AA. Increasing Distribution of Drugs Released from In Situ Forming PLGA Implants Using Therapeutic Ultrasound. Ann Biomed Eng 2017; 45:2879-2887. [PMID: 28929267 PMCID: PMC5693652 DOI: 10.1007/s10439-017-1926-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 09/12/2017] [Indexed: 12/21/2022]
Abstract
One of the challenges in developing sustained-release local drug delivery systems is the limited treatment volume that can be achieved. In this work, we examine the effectiveness of using low frequency, high intensity ultrasound to promote the spatial penetration of drug molecules away from the implant/injection site boundary upon release from injectable, phase inverting poly(lactic acid-co-glycolic acid) (PLGA) implants. Fluorescein-loaded PLGA solutions were injected into poly(acrylamide) phantoms, and the constructs were treated daily for 14 days with ultrasound at 2.2 W/cm2 for 10 min. The 2D distribution of fluorescein within the phantoms was quantified using fluorescence imaging. Implants receiving ultrasound irradiation showed a 1.7-5.6 fold increase (p < 0.05) in fluorescence intensity and penetration distance, with the maximum increase observed 5 days post-implantation. However, this evidence was not seen when the same experiment was also carried out in phosphate buffer saline (pH 7.4). Results suggest an active role of ultrasound in local molecular transport in the phantom. An increase of fluorescein release and penetration depth in phantoms can be accomplished through brief application of ultrasound. This simple technique offers an opportunity to eventually enhance the therapeutic efficacy and broaden the application of local drug delivery systems.
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Affiliation(s)
- Chawan Manaspon
- Department of Biomedical Engineering, Faculty of Engineering, Mahidol University, Nakorn Pathom, 73170, Thailand
- Department of Radiology, Case Western Reserve University, 11100 Euclid Ave, Cleveland, OH, 44106, USA
| | - Christopher Hernandez
- Department of Biomedical Engineering, Case Western Reserve University, 11100 Euclid Ave, Cleveland, OH, 44106, USA
| | - Pinunta Nittayacharn
- Department of Biomedical Engineering, Case Western Reserve University, 11100 Euclid Ave, Cleveland, OH, 44106, USA
| | - Selva Jeganathan
- Department of Biomedical Engineering, Case Western Reserve University, 11100 Euclid Ave, Cleveland, OH, 44106, USA
| | - Norased Nasongkla
- Department of Biomedical Engineering, Faculty of Engineering, Mahidol University, Nakorn Pathom, 73170, Thailand
| | - Agata A Exner
- Department of Radiology, Case Western Reserve University, 11100 Euclid Ave, Cleveland, OH, 44106, USA.
- Department of Biomedical Engineering, Case Western Reserve University, 11100 Euclid Ave, Cleveland, OH, 44106, USA.
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Brodin NP, Partanen A, Asp P, Branch CA, Guha C, Tomé WA. A simple method for determining the coagulation threshold temperature of transparent tissue-mimicking thermal therapy gel phantoms: Validated by magnetic resonance imaging thermometry. Med Phys 2016; 43:1167-74. [PMID: 26936702 DOI: 10.1118/1.4941361] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Tissue-mimicking thermal therapy phantoms that coagulate at specific temperatures are valuable tools for developing and evaluating treatment strategies related to thermal therapy. Here, the authors propose a simple and efficient method for determining the coagulation threshold temperature of transparent thermal therapy gel phantoms. METHODS The authors used a previously published gel phantom recipe with 2% (w/v) of bovine serum albumin as the temperature-sensitive protein. Using the programmable heating settings of a polymerase chain reaction (PCR) machine, the authors heated 50 μl gel samples to various temperatures for 3 min and then imaged them using the BioRad Gel Doc system to determine the coagulation temperature using an opacity quantification method. The estimated coagulation temperatures were then validated for gel phantoms prepared with different pH levels using high-intensity focused ultrasound (HIFU) heating and magnetic resonance imaging (MRI) thermometry methods on a clinical MR-HIFU system. RESULTS The PCR heating method produced consistent and reproducible coagulation of gel samples in precise correlation with the set incubation temperatures. The resulting coagulation threshold temperatures for gel phantoms of varying pH levels were found to be 44.1 ± 0.1, 53.4 ± 0.9, and 60.3 ± 0.9 °C for pH levels of 4.25, 4.50, and 4.75, respectively. This corresponded well with the coagulation threshold temperatures determined by MR-thermometry, with coagulation defined as a 95% decrease in T2 relaxation time, which were estimated at 53.6 ± 1.9 and 62.9 ± 2.4 °C for a pH of 4.50 and 4.75, respectively. CONCLUSIONS The opacity quantification method provides a fast and reproducible estimate of the coagulation threshold temperature of transparent temperature-sensitive gel phantoms. The temperatures determined using this method were well within the range of temperatures estimated using MR-thermometry. Due to the specific heating capabilities of the PCR machine, and the robust determination of coagulation threshold temperatures based on the statistically significant increase in the opacity of gel samples, coagulation temperatures can be determined more precisely and with less variability compared to MRI-based methods.
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Affiliation(s)
- N Patrik Brodin
- Institute for Onco-Physics, Albert Einstein College of Medicine, Bronx, New York 10461 and Department of Radiation Oncology, Montefiore Medical Center, Bronx, New York 10461
| | - Ari Partanen
- Clinical Science MR Therapy, Philips, Andover, Massachusetts 01810
| | - Patrik Asp
- Liver Research Center and Radiation Oncology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Craig A Branch
- Department of Radiology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Chandan Guha
- Institute for Onco-Physics, Albert Einstein College of Medicine, Bronx, New York 10461 and Department of Radiation Oncology, Montefiore Medical Center, Bronx, New York 10461
| | - Wolfgang A Tomé
- Institute for Onco-Physics, Albert Einstein College of Medicine, Bronx, New York 10461 and Department of Radiation Oncology, Montefiore Medical Center, Bronx, New York 10461
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Sun MK, Shieh J, Lo CW, Chen CS, Chen BT, Huang CW, Chen WS. Reusable tissue-mimicking hydrogel phantoms for focused ultrasound ablation. ULTRASONICS SONOCHEMISTRY 2015; 23:399-405. [PMID: 25453217 DOI: 10.1016/j.ultsonch.2014.10.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 10/07/2014] [Accepted: 10/07/2014] [Indexed: 06/04/2023]
Abstract
The ability of N-isopropylacrylamide (NIPAM)-based hydrogel phantoms to mimic tissues with different acoustic and thermal properties under high-intensity focused ultrasound (HIFU) ablation was investigated. These phantoms were designed to model the formation of thermal lesions in tissues above the threshold temperature of protein denaturation. By adjusting the concentration of acrylic acid (AAc) in the NIPAM-based hydrogel phantoms, the cloud point (i.e., lower critical solution temperature) of the phantoms could be tailored to produce HIFU thermal lesions similar to those formed in different swine tissues in terms of size and shape. Additionally, energy thresholds for inducing transient or permanent bubbles in the phantoms during HIFU ablation were also identified to shed light on the onset of cavitation or material damage. The NIPAM-based hydrogel phantoms developed in this study possess major advantages such as transparent, reusable and tailorable properties, and are practical tools for characterizing an ablative device (or treatment) to determine its efficacy and safety.
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Affiliation(s)
- Ming-Kuan Sun
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital & College of Medicine, Taipei, Taiwan; Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli, Taiwan
| | - Jay Shieh
- Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan
| | - Chia-Wen Lo
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital & College of Medicine, Taipei, Taiwan
| | - Chuin-Shan Chen
- Department of Civil Engineering, National Taiwan University, Taipei, Taiwan
| | - Ben-Ting Chen
- Department of Civil Engineering, Chung Yuan Christian University, Chung Li, Taiwan
| | - Chang-Wei Huang
- Department of Civil Engineering, Chung Yuan Christian University, Chung Li, Taiwan.
| | - Wen-Shiang Chen
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital & College of Medicine, Taipei, Taiwan; Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli, Taiwan.
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Civale J, Rivens I, ter Haar G. Quality assurance for clinical high intensity focused ultrasound fields. Int J Hyperthermia 2015; 31:193-202. [PMID: 25677839 DOI: 10.3109/02656736.2014.1002435] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
As the use of HIFU in the clinic becomes more widespread there is an ever increasing need to standardise quality assurance protocols, an important step in facilitating the wider acceptance of HIFU as a therapeutic modality. This article reviews pertinent aspects of HIFU treatment delivery, encompassing the closely related aspects of quality assurance and calibration. Particular attention is given to the description and characterisation of relevant acoustic field parameters and the measurement of acoustic power. Where appropriate, recommendations are made.
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Affiliation(s)
- John Civale
- Division of Radiotherapy and Imaging, Institute of Cancer Research , Sutton, Surrey , UK
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15
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Guntur SR, Choi MJ. An improved tissue-mimicking polyacrylamide hydrogel phantom for visualizing thermal lesions with high-intensity focused ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:2680-2691. [PMID: 25220272 DOI: 10.1016/j.ultrasmedbio.2014.06.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 06/03/2014] [Accepted: 06/17/2014] [Indexed: 06/03/2023]
Abstract
A recipe was created to improve the tissue-mimicking (TM) bovine serum albumin (BSA) polyacrylamide hydrogel (PAG) reported in our previous study (Choi MJ, Guntur SR, Lee KI, Paeng DG, Coleman AJ. Ultrasound Med Biol 2013; 29:439-448). In that work, the concentration of acrylamide in TM BSA PAG was increased to make its attenuation coefficient the same as that of a tissue. However, this increase made the PAG stiffer and less homogeneous. In addition, the increase in acrylamide caused a significant increase in temperature over the denaturation threshold of BSA during polymerization, which required forced cooling so that the PAG did not become opaque at room temperature after polymerization. To eliminate those shortcomings, we substituted the increased acrylamide with a viscous polysaccharide liquid (corn syrup). The concentration of corn syrup was optimized to 20% (w/v, tested in the volume of 50 mL), so that the acoustic properties of the PAG would be close to those of human liver. The improved TM (iTM) BSA PAG constructed in this study had a speed of sound of 1588 ± 9 m/s, an attenuation coefficient of 0.51 ± 0.06 dB cm(-1) at 1 MHz and a backscattering coefficient of 0.22 ± 0.09 × 10(-3) sr(-1) cm(-1) MHz(-1). The density and acoustic impedance were 1057 kg/m(3) and 1.68 MRayl, respectively, and the non-linear parameter (B/A) was 5.9 ± 0.3. The thermal, optical and mechanical properties were almost the same as those of the BSA PAG (Lafon et al.2005). Experimental verification indicated that the thermal lesions visualized in the proposed iTM BSA PAG by high-intensity focused ultrasound were highly reproducible. In conclusion, iTM BSA PAG was proven to eliminate TM BSA PAG shortcomings effectively and is expected to be a promising test phantom for clinical high-intensity focused ultrasound device.
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Affiliation(s)
- Sitaramanjaneya Reddy Guntur
- Interdisciplinary Postgraduate Program of Biomedical Engineering, Jeju National University, Jeju, Republic of Korea; Rajiv Gandhi Institute of Technology, Visvesvaraya Technological University, Bangalore, India
| | - Min Joo Choi
- Interdisciplinary Postgraduate Program of Biomedical Engineering, Jeju National University, Jeju, Republic of Korea; Department of Medicine, School of Medicine, Jeju National University, Jeju, Republic of Korea.
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Dabbagh A, Abdullah BJJ, Ramasindarum C, Abu Kasim NH. Tissue-mimicking gel phantoms for thermal therapy studies. ULTRASONIC IMAGING 2014; 36:291-316. [PMID: 24626566 DOI: 10.1177/0161734614526372] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Tissue-mimicking phantoms that are currently available for routine biomedical applications may not be suitable for high-temperature experiments or calibration of thermal modalities. Therefore, design and fabrication of customized thermal phantoms with tailored properties are necessary for thermal therapy studies. A multitude of thermal phantoms have been developed in liquid, solid, and gel forms to simulate biological tissues in thermal therapy experiments. This article is an attempt to outline the various materials and techniques used to prepare thermal phantoms in the gel state. The relevant thermal, electrical, acoustic, and optical properties of these phantoms are presented in detail and the benefits and shortcomings of each type are discussed. This review could assist the researchers in the selection of appropriate phantom recipes for their in vitro study of thermal modalities and highlight the limitations of current phantom recipes that remain to be addressed in further studies.
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Affiliation(s)
- Ali Dabbagh
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia University of Malaya Research Imaging Centre, University of Malaya, Kuala Lumpur, Malaysia
| | - Basri Johan Jeet Abdullah
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia University of Malaya Research Imaging Centre, University of Malaya, Kuala Lumpur, Malaysia
| | - Chanthiriga Ramasindarum
- Biomaterials Technology Research Group, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia Dental Research Management Centre, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Noor Hayaty Abu Kasim
- Biomaterials Technology Research Group, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
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Dabbagh A, Abdullah BJJ, Abu Kasim NH, Ramasindarum C. Reusable heat-sensitive phantom for precise estimation of thermal profile in hyperthermia application. Int J Hyperthermia 2013; 30:66-74. [PMID: 24286257 DOI: 10.3109/02656736.2013.854930] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
PURPOSE The emergence of thermal modalities has promoted the use of heat-sensitive phantoms for calibration, measurement, and verification purposes. However, development of durable phantoms with high precision ability to represent the temperature distribution remains a challenge. This study aims to introduce a reusable phantom that provides an accurate assessment of the heated region in various thermal modalities. MATERIALS AND METHODS The phantom contains a thermochromic dye that is transparent blue at room temperature and becomes colourless after exceeding a threshold temperature. In order to determine the threshold temperature of the phantom, spectrophotometry analysis was performed. The various thermal (specific heat, thermal conductivity, melting point and latent heat of melting) and acoustic (sound speed, attenuation) properties of this phantom were measured and compared with those of the reference phantom without dye. The application of this phantom for radio-frequency and magnetic resonance guided focused ultrasound modalities was also examined. RESULTS The spectrophotometry analysis showed a threshold temperature of 50 ± 3 °C for this phantom. The results also demonstrated a 6 °C difference between the onset and ending temperatures of the discolouration process. Moreover, the starting temperature of colouration during cooling was found to be 4 °C lower than the ending temperature of discolouration. The sound speed, attenuation, specific heat, thermal conductivity and melting point of the heat-sensitive phantom were statistically equal to those of the reference phantom; however, the latent heat, and onset temperature of the melting of the heat-sensitive phantom were decreased by addition of the dye. CONCLUSIONS The developed phantom is applicable for accurate evaluation of temperature variations in various thermal modalities.
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Affiliation(s)
- Ali Dabbagh
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya , Kuala Lumpur
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Choi MJ, Guntur SR, Lee KI, Paeng DG, Coleman A. A tissue mimicking polyacrylamide hydrogel phantom for visualizing thermal lesions generated by high intensity focused ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 2013; 39:439-448. [PMID: 23312531 DOI: 10.1016/j.ultrasmedbio.2012.10.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 09/03/2012] [Accepted: 10/02/2012] [Indexed: 06/01/2023]
Abstract
An optically transparent tissue-mimicking (TM) phantom whose acoustic properties are close to those of tissue was constructed for visualizing therapeutic effects by high intensity focused ultrasound (HIFU). The TM phantom was designed to improve a widely used standard bovine serum albumin (BSA) polyacrylamide hydrogel (PAG), which attenuated ultrasound far less than tissue and, unlike tissue, did not scatter ultrasound. A modified recipe has been proposed in the study by adding scattering glass beads with diameters of 40-80 μm (0.002% w/v) and by raising the concentration of acrylamide (30% v/v). The TM BSA-PAG constructed has an acoustic impedance of 1.67 MRayls, a speed of sound of 1576 m/s, an attenuation coefficient of 0.52 dB/cm at 1 MHz, a backscattering coefficient of 0.242 × 10(-3) 1/sr/cm at 1 MHz and a nonlinear parameter (B/A) of 5.7. These parameters are close to those of liver. The thermal and optical properties are almost the same as the standard BSA-PAG. The characteristic features of the thermal lesions by HIFU were observed to be more accurately visualized in the TM BSA-PAG than in the standard BSA-PAG. In conclusion, the proposed TM BSA-PAG acoustically mimics tissue better than the standard BSA-PAG and is expected to be preferentially used for assuring if a clinical HIFU device produces the thermal lesion as planned.
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Affiliation(s)
- Min Joo Choi
- Interdisciplinary Postgraduate Program of Biomedical Engineering, Jeju National University, Jeju, Republic of Korea.
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Dunmire B, Kucewicz JC, Mitchell SB, Crum LA, Sekins KM. Characterizing an agar/gelatin phantom for image guided dosing and feedback control of high-intensity focused ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 2013; 39:300-311. [PMID: 23245823 DOI: 10.1016/j.ultrasmedbio.2012.09.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 09/12/2012] [Accepted: 09/22/2012] [Indexed: 06/01/2023]
Abstract
The temperature dependence of an agar/gelatin phantom was evaluated. The purpose was to predict the material property response to high-intensity focused ultrasound (HIFU) for developing ultrasound guided dosing and targeting feedback. Changes in attenuation, sound speed, shear modulus and thermal properties with temperature were examined from 20°C to 70°C for 3 weeks post-manufacture. The attenuation decreased with temperature by a power factor of 0.15. Thermal conductivity, diffusivity and specific heat all increased linearly with temperature for a total change of approximately 16%, 10% and 6%, respectively. Sound speed had a parabolic dependence on temperature similar to that of water. Initially, the shear modulus irreversibly declined with even a slight increase in temperature. Over time, the gel maintained its room temperature shear modulus with moderate heating. A stable phantom was achieved within 2 weeks post-manufacture that possessed quasi-reversible material properties up to nearly 55°C.
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Affiliation(s)
- Barbrina Dunmire
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA.
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Fejerskov B, Jensen BEB, Jensen NBS, Chong SF, Zelikin AN. Engineering surface adhered poly(vinyl alcohol) physical hydrogels as enzymatic microreactors. ACS APPLIED MATERIALS & INTERFACES 2012; 4:4981-4990. [PMID: 22939117 DOI: 10.1021/am3013467] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In this work, we characterize physical hydrogels based on poly(vinyl alcohol), PVA, as intelligent biointerfaces for surface-mediated drug delivery. Specifically, we assemble microstructured (μS) surface adhered hydrogels via noncryogenic gelation of PVA, namely polymer coagulation using sodium sulfate (Na(2)SO(4)). We present systematic investigation of concentrations of Na(2)SO(4) as a tool of control over assembly of μS PVA hydrogels and quantify polymer losses and retention within the hydrogels. For polymer quantification, we use custom-made PVA with single terminal thiol group in a form of mixed disulfide with Ellman's reagent which provides for a facile UV-vis assay of polymer content in coagulation baths, subsequent washes in physiological buffer, and within the hydrogel phase. Polymer coagulation using varied concentrations of sodium sulfate afforded biointerfaces with controlled elasticity for potential uses in investigating mechano-sensitive effects of mammalian cell culture. For surface mediated drug delivery, we propose a novel concept termed Substrate Mediated Enzyme Prodrug Therapy (SMEPT) and characterize μS PVA hydrogels as reservoirs for enzymatic cargo. Assembled functional interfaces are used as matrices for cell culture and delivery of anticancer drug achieved through administration of a benign prodrug, its conversion into an active therapeutic within the hydrogel phase, and subsequent internalization by adhered hepatic cells. Taken together, the presented data contribute significantly to the development of novel matrices for surface-mediated drug delivery and other biomedical applications.
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