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Zia G, Lintz A, Hardin C, Bottiglieri A, Sebek J, Prakash P. Assessment of thermochromic phantoms for characterizing microwave ablation devices. Med Phys 2024. [PMID: 39287488 DOI: 10.1002/mp.17404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 08/22/2024] [Accepted: 08/28/2024] [Indexed: 09/19/2024] Open
Abstract
BACKGROUND AND PURPOSE Thermochromic gel phantoms provide a controlled medium for visual assessment of thermal ablation device performance. However, there are limited studies reporting on the comparative assessment of ablation profiles assessed in thermochromic gel phantoms against those in ex vivo tissue. The objective of this study was to compare microwave ablation zones in a thermochromic tissue-mimicking gel phantom and ex vivo bovine liver and to report on measurements of the temperature-dependent dielectric and thermal properties of the phantom. METHODS Thermochromic polyacrylamide phantoms were fabricated following a previously reported protocol. Phantom samples were heated to temperatures in the range of 20°C-90°C in a temperature-controlled water bath, and colorimetric analysis of images of the phantom taken after heating was used to develop a calibration between color changes and the temperature to which the phantom was heated. Using a custom, 2.45 GHz water-cooled microwave ablation antenna, ablations were performed in fresh ex vivo liver and phantoms using 65 W applied for 5 min or 10 min (n = 3 samples in each medium for each power/time combination). Broadband (500 MHz-6 GHz) temperature-dependent dielectric and thermal properties of the phantom were measured over the temperature range of 22°C-100°C. RESULTS Colorimetric analysis showed that the sharp change in gel phantom color commences at a temperature of 57°C. Short and long axes of the ablation zone in the phantom (as assessed by the 57°C isotherm) for 65 W, 5 min ablations were aligned with the extents of the ablation zone observed in ex vivo bovine liver. However, for the 65 W, 10 min setting, ablations in the phantom were on average 23.7% smaller in the short axis and 7.4 % smaller in the long axis than those observed in ex vivo liver. Measurements of the temperature-dependent relative permittivity, thermal conductivity, and volumetric heat capacity of the phantom largely followed similar trends to published values for ex vivo liver tissue. CONCLUSION Thermochromic tissue-mimicking phantoms provides a controlled, and reproducible medium for comparative assessment of microwave ablation devices and energy delivery settings. However, ablation zone size and shapes in the thermochromic phantom do not accurately represent ablation sizes and shapes observed in ex vivo liver tissue for high energy delivery treatments (65 W, 10 min). One cause for this limitation is the difference in temperature-dependent thermal and dielectric properties of the thermochromic phantom compared to ex vivo bovine liver tissue, as reported in the present study.
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Affiliation(s)
- Ghina Zia
- Department of Electrical and Computer Engineering, Kansas State University, Manhattan, Kansas, USA
| | - Amber Lintz
- Department of Electrical and Computer Engineering, Kansas State University, Manhattan, Kansas, USA
| | - Clay Hardin
- Department of Electrical and Computer Engineering, Kansas State University, Manhattan, Kansas, USA
| | - Anna Bottiglieri
- Department of Electrical and Computer Engineering, Kansas State University, Manhattan, Kansas, USA
| | - Jan Sebek
- Department of Electrical and Computer Engineering, Kansas State University, Manhattan, Kansas, USA
| | - Punit Prakash
- Department of Electrical and Computer Engineering, Kansas State University, Manhattan, Kansas, USA
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Zia G, Lintz A, Hardin C, Bottiglieri A, Sebek J, Prakash P. Assessment of thermochromic phantoms for characterizing microwave ablation devices. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.23.584886. [PMID: 38617290 PMCID: PMC11014477 DOI: 10.1101/2024.03.23.584886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Background and Purpose Thermochromic gel phantoms provide a controlled medium for visual assessment of thermal ablation device performance. However, there are limited studies reporting on the comparative assessment of ablation profiles assessed in thermochromic gel phantoms against those in ex vivo tissue. The objective of this study was to compare microwave ablation zones in a thermochromic tissue mimicking gel phantom and ex vivo bovine liver, and to report on measurements of the temperature dependent dielectric and thermal properties of the phantom. Methods Thermochromic polyacrylamide phantoms were fabricated following a previously reported protocol. Phantom samples were heated to temperatures in the range of 20 - 90 °C in a temperature-controlled water bath, and colorimetric analysis of images of the phantom taken after heating were used to develop a calibration between color changes and temperature to which the phantom was heated. Using a custom, 2.45 GHz water-cooled microwave ablation antenna, ablations were performed in fresh ex vivo liver and phantoms using 65 W applied for 5 min or 10 min ( n = 3 samples in each medium for each power/time combination). Broadband (500 MHz - 6 GHz) temperature-dependent dielectric and thermal properties of the phantom were measured over the temperature range 22 - 100 °C. Results Colorimetric analysis showed that the sharp change in gel phantom color commences at a temperature of 57 °C. Short and long axes of the ablation zone in the phantom (as assessed by the 57 °C isotherm) for 65 W, 5 min ablations were aligned with extents of the ablation zone observed in ex vivo bovine liver. However, for the 65 W, 10 min setting, ablations in the phantom were on average 23.7% smaller in short axis and 7.4 % smaller in long axis than those observed in ex vivo liver. Measurements of the temperature dependent relative permittivity, thermal conductivity, and volumetric heat capacity of the phantom largely followed similar trends to published values for ex vivo liver tissue. Conclusion Thermochromic tissue mimicking phantoms provide a controlled, and reproducible medium for comparative assessment of microwave ablation devices and energy delivery settings, though ablation zone size and shapes may not accurately represent ablation sizes and shapes observed in ex vivo liver tissue under similar conditions.
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Bossi A, Bianchi L, Saccomandi P, Pifferi A. Optical signatures of thermal damage on ex-vivo brain, lung and heart tissues using time-domain diffuse optical spectroscopy. BIOMEDICAL OPTICS EXPRESS 2024; 15:2481-2497. [PMID: 38633088 PMCID: PMC11019675 DOI: 10.1364/boe.517376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/21/2024] [Accepted: 02/21/2024] [Indexed: 04/19/2024]
Abstract
Thermal therapies treat tumors by means of heat, greatly reducing pain, post-operation complications, and cost as compared to traditional methods. Yet, effective tools to avoid under- or over-treatment are mostly needed, to guide surgeons in laparoscopic interventions. In this work, we investigated the temperature-dependent optical signatures of ex-vivo calf brain, lung, and heart tissues based on the reduced scattering and absorption coefficients in the near-infrared spectral range (657 to 1107 nm). These spectra were measured by time domain diffuse optics, applying a step-like spatially homogeneous thermal treatment at 43 °C, 60 °C, and 80 °C. We found three main increases in scattering spectra, possibly due to the denaturation of collagen, myosin, and the proteins' secondary structure. After 75 °C, we found the rise of two new peaks at 770 and 830 nm in the absorption spectra due to the formation of a new chromophore, possibly related to hemoglobin or myoglobin. This research marks a significant step forward in controlling thermal therapies with diffuse optical techniques by identifying several key markers of thermal damage. This could enhance the ability to monitor and adjust treatment in real-time, promising improved outcomes in tumor therapy.
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Affiliation(s)
- Alessandro Bossi
- Department of Mechanical Engineering, Politecnico di Milano, via Giuseppe La Masa 1, 20156 Milan, Italy
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy
| | - Leonardo Bianchi
- Department of Mechanical Engineering, Politecnico di Milano, via Giuseppe La Masa 1, 20156 Milan, Italy
| | - Paola Saccomandi
- Department of Mechanical Engineering, Politecnico di Milano, via Giuseppe La Masa 1, 20156 Milan, Italy
| | - Antonio Pifferi
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy
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Zhang S, Zhang EZ, Beard PC, Desjardins AE, Colchester RJ. Dual-modality fibre optic probe for simultaneous ablation and ultrasound imaging. COMMUNICATIONS ENGINEERING 2022; 1:s44172-022-00020-9. [PMID: 37033302 PMCID: PMC7614394 DOI: 10.1038/s44172-022-00020-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 07/13/2022] [Indexed: 11/08/2022]
Abstract
All-optical ultrasound (OpUS) is an emerging high resolution imaging paradigm utilising optical fibres. This allows both therapeutic and imaging modalities to be integrated into devices with dimensions small enough for minimally invasive surgical applications. Here we report a dual-modality fibre optic probe that synchronously performs laser ablation and real-time all-optical ultrasound imaging for ablation monitoring. The device comprises three optical fibres: one each for transmission and reception of ultrasound, and one for the delivery of laser light for ablation. The total device diameter is < 1 mm. Ablation monitoring was carried out on porcine liver and heart tissue ex vivo with ablation depth tracked using all-optical M-mode ultrasound imaging and lesion boundary identification using a segmentation algorithm. Ablation depths up to 2.1 mm were visualised with a good correspondence between the ultrasound depth measurements and visual inspection of the lesions using stereomicroscopy. This work demonstrates the potential for OpUS probes to guide minimally invasive ablation procedures in real time.
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Affiliation(s)
- Shaoyan Zhang
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, Charles Bell House, Foley Street, London, W1W 7TY UK
| | - Edward Z. Zhang
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT UK
| | - Paul C. Beard
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, Charles Bell House, Foley Street, London, W1W 7TY UK
| | - Adrien E. Desjardins
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, Charles Bell House, Foley Street, London, W1W 7TY UK
| | - Richard J. Colchester
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, Charles Bell House, Foley Street, London, W1W 7TY UK
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Arnold A, Fichera L. Identification of tissue optical properties during thermal laser-tissue interactions: An ensemble Kalman filter-based approach. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3574. [PMID: 35088944 DOI: 10.1002/cnm.3574] [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: 10/19/2021] [Revised: 01/12/2022] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
In this article, we propose a computational framework to estimate the physical properties that govern the thermal response of laser-irradiated tissue. We focus in particular on two quantities, the absorption and scattering coefficients, which describe the optical absorption of light in the tissue and whose knowledge is vital to correctly plan medical laser treatments. To perform the estimation, we utilize an implementation of the ensemble Kalman filter (EnKF), a type of Bayesian filtering algorithm for data assimilation. Unlike prior approaches, in this work, we estimate the tissue optical properties based on observations of the tissue thermal response to laser irradiation. This method has the potential for straightforward implementation in a clinical setup, as it would only require a simple thermal sensor, for example, a miniaturized infrared camera. Because the optical properties of tissue can undergo shifts during laser exposure, we employ a variant of EnKF capable of tracking time-varying parameters. Through simulated experimental studies, we demonstrate the ability of the proposed technique to identify the tissue optical properties and track their dynamic changes during laser exposure, while simultaneously tracking changes in the tissue temperature at locations beneath the surface. We further demonstrate the framework's capability in estimating additional unknown tissue properties (i.e., the volumetric heat capacity and thermal conductivity) along with the optical properties of interest.
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Affiliation(s)
- Andrea Arnold
- Department of Mathematical Sciences, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Loris Fichera
- Department of Robotics Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
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Bucharskaya AB, Khlebtsov NG, Khlebtsov BN, Maslyakova GN, Navolokin NA, Genin VD, Genina EA, Tuchin VV. Photothermal and Photodynamic Therapy of Tumors with Plasmonic Nanoparticles: Challenges and Prospects. MATERIALS (BASEL, SWITZERLAND) 2022; 15:1606. [PMID: 35208145 PMCID: PMC8878601 DOI: 10.3390/ma15041606] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/16/2022] [Accepted: 02/16/2022] [Indexed: 01/27/2023]
Abstract
Cancer remains one of the leading causes of death in the world. For a number of neoplasms, the efficiency of conventional chemo- and radiation therapies is insufficient because of drug resistance and marked toxicity. Plasmonic photothermal therapy (PPT) using local hyperthermia induced by gold nanoparticles (AuNPs) has recently been extensively explored in tumor treatment. However, despite attractive promises, the current PPT status is limited by laboratory experiments, academic papers, and only a few preclinical studies. Unfortunately, most nanoformulations still share a similar fate: great laboratory promises and fair preclinical trials. This review discusses the current challenges and prospects of plasmonic nanomedicine based on PPT and photodynamic therapy (PDT). We start with consideration of the fundamental principles underlying plasmonic properties of AuNPs to tune their plasmon resonance for the desired NIR-I, NIR-2, and SWIR optical windows. The basic principles for simulation of optical cross-sections and plasmonic heating under CW and pulsed irradiation are discussed. Then, we consider the state-of-the-art methods for wet chemical synthesis of the most popular PPPT AuNPs such as silica/gold nanoshells, Au nanostars, nanorods, and nanocages. The photothermal efficiencies of these nanoparticles are compared, and their applications to current nanomedicine are shortly discussed. In a separate section, we discuss the fabrication of gold and other nanoparticles by the pulsed laser ablation in liquid method. The second part of the review is devoted to our recent experimental results on laser-activated interaction of AuNPs with tumor and healthy tissues and current achievements of other research groups in this application area. The unresolved issues of PPT are the significant accumulation of AuNPs in the organs of the mononuclear phagocyte system, causing potential toxic effects of nanoparticles, and the possibility of tumor recurrence due to the presence of survived tumor cells. The prospective ways of solving these problems are discussed, including developing combined antitumor therapy based on combined PPT and PDT. In the conclusion section, we summarize the most urgent needs of current PPT-based nanomedicine.
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Affiliation(s)
- Alla B. Bucharskaya
- Core Facility Center, Saratov State Medical University, 112 Bol′shaya Kazachya Str., 410012 Saratov, Russia; (G.N.M.); (N.A.N.)
- Science Medical Center, Saratov State University, 83 Astrakhanskaya Str., 410012 Saratov, Russia; (V.D.G.); (E.A.G.); (V.V.T.)
- Laser Molecular Imaging and Machine Learning Laboratory, Tomsk State University, 36 Lenin′s Av., 634050 Tomsk, Russia
| | - Nikolai G. Khlebtsov
- Science Medical Center, Saratov State University, 83 Astrakhanskaya Str., 410012 Saratov, Russia; (V.D.G.); (E.A.G.); (V.V.T.)
- Nanobiotechnology Laboratory, Institute of Biochemistry and Physiology of Plants and Microorganisms RAS, FRC “Saratov Scientific Centre of the Russian Academy of Sciences”, 13 Prospekt Entuziastov, 410049 Saratov, Russia;
| | - Boris N. Khlebtsov
- Nanobiotechnology Laboratory, Institute of Biochemistry and Physiology of Plants and Microorganisms RAS, FRC “Saratov Scientific Centre of the Russian Academy of Sciences”, 13 Prospekt Entuziastov, 410049 Saratov, Russia;
| | - Galina N. Maslyakova
- Core Facility Center, Saratov State Medical University, 112 Bol′shaya Kazachya Str., 410012 Saratov, Russia; (G.N.M.); (N.A.N.)
- Science Medical Center, Saratov State University, 83 Astrakhanskaya Str., 410012 Saratov, Russia; (V.D.G.); (E.A.G.); (V.V.T.)
| | - Nikita A. Navolokin
- Core Facility Center, Saratov State Medical University, 112 Bol′shaya Kazachya Str., 410012 Saratov, Russia; (G.N.M.); (N.A.N.)
- Science Medical Center, Saratov State University, 83 Astrakhanskaya Str., 410012 Saratov, Russia; (V.D.G.); (E.A.G.); (V.V.T.)
| | - Vadim D. Genin
- Science Medical Center, Saratov State University, 83 Astrakhanskaya Str., 410012 Saratov, Russia; (V.D.G.); (E.A.G.); (V.V.T.)
- Laser Molecular Imaging and Machine Learning Laboratory, Tomsk State University, 36 Lenin′s Av., 634050 Tomsk, Russia
| | - Elina A. Genina
- Science Medical Center, Saratov State University, 83 Astrakhanskaya Str., 410012 Saratov, Russia; (V.D.G.); (E.A.G.); (V.V.T.)
- Laser Molecular Imaging and Machine Learning Laboratory, Tomsk State University, 36 Lenin′s Av., 634050 Tomsk, Russia
| | - Valery V. Tuchin
- Science Medical Center, Saratov State University, 83 Astrakhanskaya Str., 410012 Saratov, Russia; (V.D.G.); (E.A.G.); (V.V.T.)
- Laser Molecular Imaging and Machine Learning Laboratory, Tomsk State University, 36 Lenin′s Av., 634050 Tomsk, Russia
- Institute of Precision Mechanics and Control, FRC “Saratov Scientific Centre of the Russian Academy of Sciences”, 24 Rabochaya Str., 410028 Saratov, Russia
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Wang J. Real-time calibrating polarization-sensitive diffuse reflectance handheld probe characterizes clinically relevant anatomical locations of oral tissue in vivo. BIOMEDICAL OPTICS EXPRESS 2022; 13:105-116. [PMID: 35154857 PMCID: PMC8803026 DOI: 10.1364/boe.443652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 11/15/2021] [Accepted: 11/29/2021] [Indexed: 05/10/2023]
Abstract
We report on the development of a unique real-time calibrating polarization-sensitive diffuse reflectance (rcPS-DR) handheld probe, and demonstrate its diagnostic potential through in-depth characterization and differentiation of clinically relevant anatomical locations of the oral cavity (i.e., alveolar process, lateral tongue and floor of mouth that account for 80% of all cases of oral squamous cell carcinoma) in vivo. With an embedded calibrating polytetrafluoroethylene (PTFE) optical diffuser, the PS-DR spectra bias arising from instrument response, time-dependent intensity fluctuation and fiber bending is calibrated through real-time measurement of the PS-DR system response function. A total of 554 in vivo rcPS-DR spectra were acquired from different oral tissue sites (alveolar process, n = 226, lateral tongue, n = 150 and floor of mouth, n = 178) of 14 normal subjects. Significantly (P<0.05, unpaired 2-sided Student's t-test) different spectral ratio (I 540/I 575) representing oxygenated hemoglobin contents were found among the alveolar process, lateral tongue and floor of mouth. Further partial least squares discriminant analysis (PLS-DA) and leave-one-out, cross validation (LOOCV) show that, synergizing the complementary information of the two real-time calibrated orthogonal-polarized PS-DR spectra, the rcPS-DR technique is found to better differentiate alveolar process, lateral tongue, and the floor of mouth (accuracies of 88.2%, 83.9%, 84.4%, sensitivities of 80.5%, 75.8%, 78% and specificities of 93.5%, 87.7%, 86.8%) than standard DR (accuracies of 80.8%, 72.9%, 68.5%, sensitivities of 63.2%, 41.5%, 81.3% and specificities of 92.9%, 87.7%, 63.8%) without PS detection. This work showed the feasibility of the rcPS-DR probe as a tool for studying oral cavity lesions in real clinical applications.
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Affiliation(s)
- Jianfeng Wang
- Key Laboratory of Photoelectronic Imaging Technology and System of Ministry of Education of China, School of Optics and Photonics, Beijingy Institute of Technology, Beijing 100081, China
- Institute of Engineering Medicine, Beijing Institute of Technology, Beijing 100081, China
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Radiofrequency Ablation for Liver: Comparison between Expert Eye and Hyperspectral Imaging Assessment. Photodiagnosis Photodyn Ther 2021; 37:102699. [PMID: 34942401 DOI: 10.1016/j.pdpdt.2021.102699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 12/14/2021] [Accepted: 12/17/2021] [Indexed: 11/27/2022]
Abstract
Liver/hepatic cancer (HC) is a disease that roughly afflicts 10% of cancer patients worldwide. HC is in charge of the death of 0.8 million patients on the earth. Multiple approaches, including thermal ablation, target the treatment of HC. In this study, we investigated radiofrequency (RF) ablation. Expert clinicians' visual assessment (VA) dominantly evaluated the outcome of ablation. Inattentively, the disfavors of VA are being subjective and eye-acuity dependent. In support, we propose hyperspectral imaging (HSI) for objective assessment of liver ablation. To verify our proposal, we computed the ablated liver area using VA and HSI. Unfortunately, HSI is a time-intensive technique. To make it less intensive, we present a way of reducing data analysis time. Saving time permits medical decisions, likewise continue or stop RF ablation, to be taken safer and faster. The way to reduce the time for HSI data analysis depends on narrowing the spectral bands of interest to only the most relevant ones to liver chromophores. Liver chromophores change in concentration because of thermal ablation. VA hardly senses these changes, however, HSI does it. Ultimately, the spectral band centered at 630 nm is optimal for objectively support RF ablation decision-makers.
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Prediction of In Vivo Laser-Induced Thermal Damage with Hyperspectral Imaging Using Deep Learning. SENSORS 2021; 21:s21206934. [PMID: 34696147 PMCID: PMC8539534 DOI: 10.3390/s21206934] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/11/2021] [Accepted: 10/15/2021] [Indexed: 12/26/2022]
Abstract
Thermal ablation is an acceptable alternative treatment for primary liver cancer, of which laser ablation (LA) is one of the least invasive approaches, especially for tumors in high-risk locations. Precise control of the LA effect is required to safely destroy the tumor. Although temperature imaging techniques provide an indirect measurement of the thermal damage, a degree of uncertainty remains about the treatment effect. Optical techniques are currently emerging as tools to directly assess tissue thermal damage. Among them, hyperspectral imaging (HSI) has shown promising results in image-guided surgery and in the thermal ablation field. The highly informative data provided by HSI, associated with deep learning, enable the implementation of non-invasive prediction models to be used intraoperatively. Here we show a novel paradigm “peak temperature prediction model” (PTPM), convolutional neural network (CNN)-based, trained with HSI and infrared imaging to predict LA-induced damage in the liver. The PTPM demonstrated an optimal agreement with tissue damage classification providing a consistent threshold (50.6 ± 1.5 °C) for the damage margins with high accuracy (~0.90). The high correlation with the histology score (r = 0.9085) and the comparison with the measured peak temperature confirmed that PTPM preserves temperature information accordingly with the histopathological assessment.
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Theoretical Evaluation of Microwave Ablation Applied on Muscle, Fat and Bone: A Numerical Study. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11178271] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
(1) Background: Microwave ablation (MWA) is a common tumor ablation surgery. Because of the high temperature of the ablation antenna, it is strongly destructive to surrounding vital tissues, resulting in high professional requirements for clinicians. The method used to carry out temperature observation and damage prediction in MWA is significant; (2) Methods: This work employs numerical study to explore temperature distribution of typical tissues in MWA. Firstly, clinical MWA based on isolated biological tissue is implemented. Then, the Pennes models and microwave radiation physics are established based on experimental parameters and existing related research. Initial values and boundary conditions are adjusted to better meet the real clinical materials and experimental conditions. Finally, clinical MWA data test this model. On the premise that the model is matched with clinical MWA, fat and bone are deduced for further heat transfer analysis. (3) Results: Numerical study obtains the temperature distribution of biological tissue in MWA. It observes the heat transfer law of ablation antenna in biological tissue. Additionally, combined with temperature threshold, it generates thermal damage of biological tissues and predicts the possible risks in MWA; (4) Conclusions: This work proposes a numerical study of typical biological tissues. It provides a new theoretical basis for clinically thermal ablation surgery.
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Voulgarelis S, Fathi F, Stucke AG, Daley KD, Kim J, Zimmerman MA, Hong JC, Starkey N, Allen KP, Yu B. Evaluation of visible diffuse reflectance spectroscopy in liver tissue: validation of tissue saturations using extracorporeal circulation. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210019R. [PMID: 34021537 PMCID: PMC8145982 DOI: 10.1117/1.jbo.26.5.055002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 05/03/2021] [Indexed: 05/13/2023]
Abstract
SIGNIFICANCE Real-time information about oxygen delivery to the hepatic graft is important to direct care and diagnose vascular compromise in the immediate post-transplant period. AIM The current study was designed to determine the utility of visible diffuse reflectance spectroscopy (vis-DRS) for measuring liver tissue saturation in vivo. APPROACH A custom-built vis-DRS probe was calibrated using phantoms with hemoglobin (Hb) and polystyrene microspheres. Ex vivo (extracorporeal circulation) and in vivo protocols were used in a swine model (n = 15) with validation via blood gas analysis. RESULTS In vivo absorption and scattering measured by vis-DRS with and without biliverdin correction correlated closely between analyses. Lin's concordance correlation coefficients are 0.991 for μa and 0.959 for μs ' . Hb measured by blood test and vis-DRS with (R2 = 0.81) and without (R2 = 0.85) biliverdin correction were compared. Vis-DRS data obtained from the ex vivo protocol plotted against the PO2 derived from blood gas analysis showed a good fit for a Hill coefficient of 1.67 and P50 = 34 mmHg (R2 = 0.81). A conversion formula was developed to account for the systematic deviation, which resulted in a goodness-of-fit R2 = 0.76 with the expected oxygen dissociation curve. CONCLUSIONS We show that vis-DRS allows for real-time measurement of liver tissue saturation, an indicator for liver perfusion and oxygen delivery.
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Affiliation(s)
- Stylianos Voulgarelis
- Medical College of Wisconsin, Children’s Wisconsin, Department of Anesthesiology, Milwaukee, Wisconsin, United States
- Address all correspondence to Stylianos Voulgarelis,
| | - Faraneh Fathi
- Marquette University and Medical College of Wisconsin, Department of Biomedical Engineering, Milwaukee, Wisconsin, United States
| | - Astrid G. Stucke
- Medical College of Wisconsin, Children’s Wisconsin, Department of Anesthesiology, Milwaukee, Wisconsin, United States
| | - Kevin D. Daley
- Herma Heart Institute, Children’s Wisconsin, Department of Perfusion, Milwaukee, Wisconsin, United States
| | - Joohyun Kim
- Medical College of Wisconsin, Children’s Hospital of Wisconsin, Department of Surgery, Division of Transplant Surgery, Milwaukee, Wisconsin, United States
| | - Michael A. Zimmerman
- Medical College of Wisconsin, Children’s Hospital of Wisconsin, Department of Surgery, Division of Transplant Surgery, Milwaukee, Wisconsin, United States
| | - Johnny C. Hong
- Medical College of Wisconsin, Children’s Hospital of Wisconsin, Department of Surgery, Division of Transplant Surgery, Milwaukee, Wisconsin, United States
| | - Nicholas Starkey
- Herma Heart Institute, Children’s Wisconsin, Department of Perfusion, Milwaukee, Wisconsin, United States
| | - Kenneth P. Allen
- Biomedical Resource Center, Medical College of Wisconsin, Department of Immunology Microbiology, Milwaukee, Wisconsin, United States
| | - Bing Yu
- Marquette University and Medical College of Wisconsin, Department of Biomedical Engineering, Milwaukee, Wisconsin, United States
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Bianchi L, Korganbayev S, Orrico A, De Landro M, Saccomandi P. Quasi-distributed fiber optic sensor-based control system for interstitial laser ablation of tissue: theoretical and experimental investigations. BIOMEDICAL OPTICS EXPRESS 2021; 12:2841-2858. [PMID: 34168905 PMCID: PMC8194627 DOI: 10.1364/boe.419541] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/12/2021] [Accepted: 03/23/2021] [Indexed: 05/08/2023]
Abstract
This work proposes the quasi-distributed real-time monitoring and control of laser ablation (LA) of liver tissue. To confine the thermal damage, a pre-planning stage of the control strategy based on numerical simulations of the bioheat-transfer was developed to design the control parameters, then experimentally assessed. Fiber Bragg grating (FBG) sensors were employed to design the automatic thermometry system used for temperature feedback control for interstitial LA. The tissue temperature was maintained at a pre-set value, and the influence of different sensor locations (on the direction of the beam propagation and backward) on the thermal outcome was evaluated in comparison with the uncontrolled case. Results show that the implemented computational model was able to properly describe the temperature evolution of the irradiated tissue. Furthermore, the realized control strategy allowed for the accurate confinement of the laser-induced temperature increase, especially when the temperature control was actuated by sensors located in the direction of the beam propagation, as confirmed by the calculated fractions of necrotic tissues (e.g., 23 mm3 and 53 mm3 for the controlled and uncontrolled LA, respectively).
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De Landro M, Espíritu García-Molina I, Barberio M, Felli E, Agnus V, Pizzicannella M, Diana M, Zappa E, Saccomandi P. Hyperspectral Imagery for Assessing Laser-Induced Thermal State Change in Liver. SENSORS 2021; 21:s21020643. [PMID: 33477656 PMCID: PMC7831494 DOI: 10.3390/s21020643] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/05/2021] [Accepted: 01/13/2021] [Indexed: 12/16/2022]
Abstract
This work presents the potential of hyperspectral imaging (HSI) to monitor the thermal outcome of laser ablation therapy used for minimally invasive tumor removal. Our main goal is the establishment of indicators of the thermal damage of living tissues, which can be used to assess the effect of the procedure. These indicators rely on the spectral variation of temperature-dependent tissue chromophores, i.e., oxyhemoglobin, deoxyhemoglobin, methemoglobin, and water. Laser treatment was performed at specific temperature thresholds (from 60 to 110 °C) on in-vivo animal liver and was assessed with a hyperspectral camera (500-995 nm) during and after the treatment. The indicators were extracted from the hyperspectral images after the following processing steps: the breathing motion compensation and the spectral and spatial filtering, the selection of spectral bands corresponding to specific tissue chromophores, and the analysis of the areas under the curves for each spectral band. Results show that properly combining spectral information related to deoxyhemoglobin, methemoglobin, lipids, and water allows for the segmenting of different zones of the laser-induced thermal damage. This preliminary investigation provides indicators for describing the thermal state of the liver, which can be employed in the future as clinical endpoints of the procedure outcome.
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Affiliation(s)
- Martina De Landro
- Department of Mechanical Engineering, Politecnico di Milano, 20156 Milan, Italy; (M.D.L.); (I.E.G.-M.); (E.Z.)
| | | | - Manuel Barberio
- IHU-Strasbourg, 67000 Strasbourg, France; (M.B.); (E.F.); (V.A.); (M.P.); (M.D.)
- Department of General Surgery, Ospedale Card. G. Panico, 73039 Tricase, Italy
| | - Eric Felli
- IHU-Strasbourg, 67000 Strasbourg, France; (M.B.); (E.F.); (V.A.); (M.P.); (M.D.)
| | - Vincent Agnus
- IHU-Strasbourg, 67000 Strasbourg, France; (M.B.); (E.F.); (V.A.); (M.P.); (M.D.)
| | | | - Michele Diana
- IHU-Strasbourg, 67000 Strasbourg, France; (M.B.); (E.F.); (V.A.); (M.P.); (M.D.)
- Research Institute against Cancer of the Digestive System IRCAD, 67091 Strasbourg, France
- ICube Laboratory, Photonics Instrumentation for Health, 67400 Strasbourg, France
| | - Emanuele Zappa
- Department of Mechanical Engineering, Politecnico di Milano, 20156 Milan, Italy; (M.D.L.); (I.E.G.-M.); (E.Z.)
| | - Paola Saccomandi
- Department of Mechanical Engineering, Politecnico di Milano, 20156 Milan, Italy; (M.D.L.); (I.E.G.-M.); (E.Z.)
- Correspondence:
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Iorizzo TW, Jermain PR, Salomatina E, Muzikansky A, Yaroslavsky AN. Temperature induced changes in the optical properties of skin in vivo. Sci Rep 2021; 11:754. [PMID: 33436982 PMCID: PMC7803738 DOI: 10.1038/s41598-020-80254-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 12/17/2020] [Indexed: 12/02/2022] Open
Abstract
Knowledge of temperature-induced changes of skin optical properties is required for accurate dosimetry of photothermal treatments. We determined and compared in vivo optical properties of mouse ear skin at different temperatures. The diffuse reflectance, total and diffuse transmittance were measured in the spectral range from 400 to 1650 nm using an integrating sphere spectrometer at the temperatures of 25 °C, 36 °C and 60 °C. Target temperatures were attained and maintained using an automated heater equipped with a sensor for feed-back and control. Temperature and temperature induced morphological changes of skin were monitored using an infrared thermal camera and reflectance confocal microscopy, respectively. An inverse Monte Carlo technique was utilized to determine absorption, scattering, and anisotropy factors from the measured quantities. Our results indicate significant differences between the optical properties of skin at different temperatures. Absorption and scattering coefficients increased, whereas anisotropy factors decreased with increasing temperature. Changes in absorption coefficients indicate deoxygenation of hemoglobin, and a blue shift of water absorption bands. Confocal imaging confirmed that our observations can be explained by temperature induced protein denaturation and blood coagulation. Monitoring spectral responses of treated tissue may become a valuable tool for accurate dosimetry of light treatments.
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Affiliation(s)
- Tyler W Iorizzo
- Advanced Biophotonics Laboratory, University of Massachusetts Lowell, 175 Cabot Street, Lowell, MA, 01854, USA
| | - Peter R Jermain
- Advanced Biophotonics Laboratory, University of Massachusetts Lowell, 175 Cabot Street, Lowell, MA, 01854, USA
| | - Elena Salomatina
- Department of Dermatology, Massachusetts General Hospital, 50 Staniford Street, Boston, MA, 02114, USA
| | - Alona Muzikansky
- Biostatistics Center, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Anna N Yaroslavsky
- Advanced Biophotonics Laboratory, University of Massachusetts Lowell, 175 Cabot Street, Lowell, MA, 01854, USA. .,Department of Dermatology, Massachusetts General Hospital, 50 Staniford Street, Boston, MA, 02114, USA.
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Korganbayev S, Orrico A, Bianchi L, De Landro M, Wolf A, Dostovalov A, Saccomandi P. Closed-Loop Temperature Control Based on Fiber Bragg Grating Sensors for Laser Ablation of Hepatic Tissue. SENSORS 2020; 20:s20226496. [PMID: 33203048 PMCID: PMC7697476 DOI: 10.3390/s20226496] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 10/27/2020] [Accepted: 11/11/2020] [Indexed: 12/13/2022]
Abstract
Laser ablation (LA) of cancer is a minimally invasive technique based on targeted heat release. Controlling tissue temperature during LA is crucial to achieve the desired therapeutic effect in the organs while preserving the healthy tissue around. Here, we report the design and implementation of a real-time monitoring system performing closed-loop temperature control, based on fiber Bragg grating (FBG) spatial measurements. Highly dense FBG arrays (1.19 mm length, 0.01 mm edge-to-edge distance) were inscribed in polyimide-coated fibers using the femtosecond point-by-point writing technology to obtain the spatial resolution needed for accurate reconstruction of high-gradient temperature profiles during LA. The zone control strategy was implemented such that the temperature in the laser-irradiated area was maintained at specific set values (43 and 55 °C), in correspondence to specific radii (2 and 6 mm) of the targeted zone. The developed control system was assessed in terms of measured temperature maps during an ex vivo liver LA. Results suggest that the temperature-feedback system provides several advantages, including controlling the margins of the ablated zone and keeping the maximum temperature below the critical values. Our strategy and resulting analysis go beyond the state-of-the-art LA regulation techniques, encouraging further investigation in the identification of the optimal control-loop.
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Affiliation(s)
- Sanzhar Korganbayev
- Department of Mechanical Engineering, Politecnico di Milano Milan, 20133 Milano MI, Italy; (A.O.); (L.B.); (M.D.L.); (P.S.)
- Correspondence: ; Tel.: +39-348-776-1649
| | - Annalisa Orrico
- Department of Mechanical Engineering, Politecnico di Milano Milan, 20133 Milano MI, Italy; (A.O.); (L.B.); (M.D.L.); (P.S.)
| | - Leonardo Bianchi
- Department of Mechanical Engineering, Politecnico di Milano Milan, 20133 Milano MI, Italy; (A.O.); (L.B.); (M.D.L.); (P.S.)
| | - Martina De Landro
- Department of Mechanical Engineering, Politecnico di Milano Milan, 20133 Milano MI, Italy; (A.O.); (L.B.); (M.D.L.); (P.S.)
| | - Alexey Wolf
- Laboratory of Fiber Optics, Institute of Automation and Electrometry SB RAS, Novosibirsk 630090, Russia; (A.W.); (A.D.)
| | - Alexander Dostovalov
- Laboratory of Fiber Optics, Institute of Automation and Electrometry SB RAS, Novosibirsk 630090, Russia; (A.W.); (A.D.)
| | - Paola Saccomandi
- Department of Mechanical Engineering, Politecnico di Milano Milan, 20133 Milano MI, Italy; (A.O.); (L.B.); (M.D.L.); (P.S.)
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Biswas D, Chen GCK, Baac HW, Vasudevan S. Photoacoustic Spectral Sensing Technique for Diagnosis of Biological Tissue Coagulation: In-Vitro Study. Diagnostics (Basel) 2020; 10:diagnostics10030133. [PMID: 32121418 PMCID: PMC7151006 DOI: 10.3390/diagnostics10030133] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 02/17/2020] [Accepted: 02/24/2020] [Indexed: 01/20/2023] Open
Abstract
Thermal coagulation of abnormal tissues has evolved as a therapeutic technique for different diseases including cancer. Tissue heating beyond 55 °C causes coagulation that leads to cell death. Noninvasive diagnosis of thermally coagulated tissues is pragmatic for performing efficient therapy as well as reducing damage of surrounding healthy tissues. We propose a noninvasive, elasticity-based photoacoustic spectral sensing technique for differentiating normal and coagulated tissues. Photoacoustic diagnosis is performed for quantitative differentiation of normal and coagulated excised chicken liver and muscle tissues in vitro by characterizing a dominant frequency of photoacoustic frequency spectrum. Pronounced distinction in the spectral parameter (i.e., dominant frequency) was observed due to change in tissue elastic property. We confirmed nearly two-fold increase in dominant frequencies for the coagulated muscle and liver tissues as compared to the normal ones. A density increase caused by tissue coagulation is clearly reflected in the dominant frequency composition. Experimental results were consistent over five different sample sets, delineating the potential of proposed technique to diagnose biological tissue coagulation and thus monitor thermal coagulation therapy in clinical applications.
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Affiliation(s)
- Deblina Biswas
- Discipline of Electrical Engineering, Indian Institute of Technology Indore, Khandwa Road, Simrol, Madhya Pradesh 453552, India;
- Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 440-746, Korea
| | | | - Hyoung Won Baac
- Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 440-746, Korea
- Correspondence: (H.W.B.); (S.V.)
| | - Srivathsan Vasudevan
- Discipline of Electrical Engineering, Indian Institute of Technology Indore, Khandwa Road, Simrol, Madhya Pradesh 453552, India;
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Khandwa Road, Simrol, Madhya Pradesh 453552, India
- Correspondence: (H.W.B.); (S.V.)
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