1
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Liu LP, Hwang M, Hung M, Soulen MC, Schaer TP, Shapira N, Noël PB. Non-invasive mass and temperature quantifications with spectral CT. Sci Rep 2023; 13:6109. [PMID: 37059839 PMCID: PMC10104802 DOI: 10.1038/s41598-023-33264-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 04/11/2023] [Indexed: 04/16/2023] Open
Abstract
Spectral CT has been increasingly implemented clinically for its better characterization and quantification of materials through its multi-energy results. It also facilitates calculation of physical density, allowing for non-invasive mass measurements and temperature evaluations by manipulating the definition of physical density and thermal volumetric expansion, respectively. To develop spectral physical density quantifications, original and parametrized Alvarez-Macovski model and electron density-physical density model were validated with a phantom. The best physical density model was then implemented on clinical spectral CT scans of ex vivo bovine muscle to determine the accuracy and effect of acquisition parameters on mass measurements. In addition, the relationship between physical density and changes in temperature was evaluated by scanning and subjecting the tissue to a range of temperatures. The parametrized Alvarez-Macovski model performed best in both model development and validation with errors within ± 0.02 g/mL. No effect from acquisition parameters was observed in mass measurements, which demonstrated accuracy with a maximum percent error of 0.34%. Furthermore, physical density was strongly correlated (R of 0.9781) to temperature changes through thermal volumetric expansion. Accurate and precise spectral physical density quantifications enable non-invasive mass measurements for pathological detection and temperature evaluation for thermal therapy monitoring in interventional oncology.
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Affiliation(s)
- Leening P Liu
- Department of Radiology, University of Pennsylvania, Philadelphia, USA.
- Department of Bioengineering, University of Pennsylvania, Philadelphia, USA.
| | | | - Matthew Hung
- Department of Radiology, University of Pennsylvania, Philadelphia, USA
| | - Michael C Soulen
- Department of Radiology, University of Pennsylvania, Philadelphia, USA
| | - Thomas P Schaer
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, USA
| | - Nadav Shapira
- Department of Radiology, University of Pennsylvania, Philadelphia, USA
| | - Peter B Noël
- Department of Radiology, University of Pennsylvania, Philadelphia, USA
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2
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Wang N, Li M, Haverinen P. Photon-counting computed tomography thermometry via material decomposition and machine learning. Vis Comput Ind Biomed Art 2023; 6:2. [PMID: 36640198 PMCID: PMC9840722 DOI: 10.1186/s42492-022-00129-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/22/2022] [Indexed: 01/15/2023] Open
Abstract
Thermal ablation procedures, such as high intensity focused ultrasound and radiofrequency ablation, are often used to eliminate tumors by minimally invasively heating a focal region. For this task, real-time 3D temperature visualization is key to target the diseased tissues while minimizing damage to the surroundings. Current computed tomography (CT) thermometry is based on energy-integrated CT, tissue-specific experimental data, and linear relationships between attenuation and temperature. In this paper, we develop a novel approach using photon-counting CT for material decomposition and a neural network to predict temperature based on thermal characteristics of base materials and spectral tomographic measurements of a volume of interest. In our feasibility study, distilled water, 50 mmol/L CaCl2, and 600 mmol/L CaCl2 are chosen as the base materials. Their attenuations are measured in four discrete energy bins at various temperatures. The neural network trained on the experimental data achieves a mean absolute error of 3.97 °C and 1.80 °C on 300 mmol/L CaCl2 and a milk-based protein shake respectively. These experimental results indicate that our approach is promising for handling non-linear thermal properties for materials that are similar or dissimilar to our base materials.
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Affiliation(s)
- Nathan Wang
- grid.21107.350000 0001 2171 9311Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Mengzhou Li
- grid.33647.350000 0001 2160 9198Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180 USA
| | - Petteri Haverinen
- grid.5373.20000000108389418Aalto Design Factory, Aalto University, Espoo, 02150 Finland
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3
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Geoghegan R, Ter Haar G, Nightingale K, Marks L, Natarajan S. Methods of monitoring thermal ablation of soft tissue tumors - A comprehensive review. Med Phys 2022; 49:769-791. [PMID: 34965307 DOI: 10.1002/mp.15439] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 11/30/2020] [Accepted: 12/15/2021] [Indexed: 11/12/2022] Open
Abstract
Thermal ablation is a form of hyperthermia in which oncologic control can be achieved by briefly inducing elevated temperatures, typically in the range 50-80°C, within a target tissue. Ablation modalities include high intensity focused ultrasound, radiofrequency ablation, microwave ablation, and laser interstitial thermal therapy which are all capable of generating confined zones of tissue destruction, resulting in fewer complications than conventional cancer therapies. Oncologic control is contingent upon achieving predefined coagulation zones; therefore, intraoperative assessment of treatment progress is highly desirable. Consequently, there is a growing interest in the development of ablation monitoring modalities. The first section of this review presents the mechanism of action and common applications of the primary ablation modalities. The following section outlines the state-of-the-art in thermal dosimetry which includes interstitial thermal probes and radiologic imaging. Both the physical mechanism of measurement and clinical or pre-clinical performance are discussed for each ablation modality. Thermal dosimetry must be coupled with a thermal damage model as outlined in Section 4. These models estimate cell death based on temperature-time history and are inherently tissue specific. In the absence of a reliable thermal model, the utility of thermal monitoring is greatly reduced. The final section of this review paper covers technologies that have been developed to directly assess tissue conditions. These approaches include visualization of non-perfused tissue with contrast-enhanced imaging, assessment of tissue mechanical properties using ultrasound and magnetic resonance elastography, and finally interrogation of tissue optical properties with interstitial probes. In summary, monitoring thermal ablation is critical for consistent clinical success and many promising technologies are under development but an optimal solution has yet to achieve widespread adoption.
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Affiliation(s)
- Rory Geoghegan
- Department of Urology, University of California Los Angeles, Los Angeles, California, USA
| | - Gail Ter Haar
- Department of Physics, Institute of Cancer Research, University of London, Sutton, UK
| | - Kathryn Nightingale
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
| | - Leonard Marks
- Department of Urology, University of California Los Angeles, Los Angeles, California, USA
| | - Shyam Natarajan
- Departments of Urology & Bioengineering, University of California Los Angeles, Los Angeles, California, USA
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4
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Heinrich A, Schenkl S, Buckreus D, Güttler FV, Teichgräber UKM. CT-based thermometry with virtual monoenergetic images by dual-energy of fat, muscle and bone using FBP, iterative and deep learning-based reconstruction. Eur Radiol 2021; 32:424-431. [PMID: 34327575 PMCID: PMC8660750 DOI: 10.1007/s00330-021-08206-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/07/2021] [Indexed: 12/24/2022]
Abstract
Objectives The aim of this study was to evaluate the sensitivity of CT-based thermometry for clinical applications regarding a three-component tissue phantom of fat, muscle and bone. Virtual monoenergetic images (VMI) by dual-energy measurements and conventional polychromatic 120-kVp images with modern reconstruction algorithms adaptive statistical iterative reconstruction-Volume (ASIR-V) and deep learning image reconstruction (DLIR) were compared. Methods A temperature-regulating water circuit system was developed for the systematic evaluation of the correlation between temperature and Hounsfield units (HU). The measurements were performed on a Revolution CT with gemstone spectral imaging technology (GSI). Complementary measurements were performed without GSI (voltage 120 kVp, current 130–545 mA). The measured object was a tissue equivalent phantom in a temperature range of 18 to 50°C. The evaluation was carried out for VMI at 40 to 140 keV and polychromatic 120-kVp images. Results The regression analysis showed a significant inverse linear dependency between temperature and average HU regardless of ASIR-V and DLIR. VMI show a higher temperature sensitivity compared to polychromatic images. The temperature sensitivities were 1.25 HU/°C (120 kVp) and 1.35 HU/°C (VMI at 140 keV) for fat, 0.38 HU/°C (120 kVp) and 0.47 HU/°C (VMI at 40 keV) for muscle and 1.15 HU/°C (120 kVp) and 3.58 HU/°C (VMI at 50 keV) for bone. Conclusions Dual-energy with VMI enables a higher temperature sensitivity for fat, muscle and bone. The reconstruction with ASIR-V and DLIR has no significant influence on CT-based thermometry, which opens up the potential of drastic dose reductions. Key Points • Virtual monoenergetic images (VMI) enable a higher temperature sensitivity for fat (8%), muscle (24%) and bone (211%) compared to conventional polychromatic 120-kVp images. • With VMI, there are parameters, e.g. monoenergy and reconstruction kernel, to modulate the temperature sensitivity. In contrast, there are no parameters to influence the temperature sensitivity for conventional polychromatic 120-kVp images. • The application of adaptive statistical iterative reconstruction-Volume (ASIR-V) and deep learning–based image reconstruction (DLIR) has no effect on CT-based thermometry, opening up the potential of drastic dose reductions in clinical applications.
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Affiliation(s)
- Andreas Heinrich
- Department of Radiology, Jena University Hospital - Friedrich Schiller University, Am Klinikum 1, 07747, Jena, Germany.
| | - Sebastian Schenkl
- Institute of Forensic Medicine, Jena University Hospital - Friedrich Schiller University, Am Klinikum 1, 07747, Jena, Germany
| | - David Buckreus
- Department of Radiology, Jena University Hospital - Friedrich Schiller University, Am Klinikum 1, 07747, Jena, Germany
| | - Felix V Güttler
- Department of Radiology, Jena University Hospital - Friedrich Schiller University, Am Klinikum 1, 07747, Jena, Germany
| | - Ulf K-M Teichgräber
- Department of Radiology, Jena University Hospital - Friedrich Schiller University, Am Klinikum 1, 07747, Jena, Germany
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Zaltieri M, Massaroni C, Cauti FM, Schena E. Techniques for Temperature Monitoring of Myocardial Tissue Undergoing Radiofrequency Ablation Treatments: An Overview. SENSORS (BASEL, SWITZERLAND) 2021; 21:1453. [PMID: 33669692 PMCID: PMC7922285 DOI: 10.3390/s21041453] [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: 01/29/2021] [Revised: 02/12/2021] [Accepted: 02/16/2021] [Indexed: 12/18/2022]
Abstract
Cardiac radiofrequency ablation (RFA) has received substantial attention for the treatment of multiple arrhythmias. In this scenario, there is an ever-growing demand for monitoring the temperature trend inside the tissue as it may allow an accurate control of the treatment effects, with a consequent improvement of the clinical outcomes. There are many methods for monitoring temperature in tissues undergoing RFA, which can be divided into invasive and non-invasive. This paper aims to provide an overview of the currently available techniques for temperature detection in this clinical scenario. Firstly, we describe the heat generation during RFA, then we report the principle of work of the most popular thermometric techniques and their features. Finally, we introduce their main applications in the field of cardiac RFA to explore the applicability in clinical settings of each method.
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Affiliation(s)
- Martina Zaltieri
- Department of Engineering, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 00128 Rome, Italy; (M.Z.); (C.M.)
| | - Carlo Massaroni
- Department of Engineering, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 00128 Rome, Italy; (M.Z.); (C.M.)
| | - Filippo Maria Cauti
- Arrhythmology Unit, Cardiology Division, S. Giovanni Calibita Hospital, Isola Tiberina, 00186 Rome, Italy;
| | - Emiliano Schena
- Department of Engineering, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 00128 Rome, Italy; (M.Z.); (C.M.)
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6
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Asadi S, Bianchi L, De Landro M, Korganbayev S, Schena E, Saccomandi P. Laser-induced optothermal response of gold nanoparticles: From a physical viewpoint to cancer treatment application. JOURNAL OF BIOPHOTONICS 2021; 14:e202000161. [PMID: 32761778 DOI: 10.1002/jbio.202000161] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/15/2020] [Accepted: 07/28/2020] [Indexed: 06/11/2023]
Abstract
Gold nanoparticles (GNPs)-based photothermal therapy (PTT) is a promising minimally invasive thermal therapy for the treatment of focal malignancies. Although GNPs-based PTT has been known for over two decades and GNPs possess unique properties as therapeutic agents, the delivery of a safe and effective therapy is still an open question. This review aims at providing relevant and recent information on the usage of GNPs in combination with the laser to treat cancers, pointing out the practical aspects that bear on the therapy outcome. Emphasis is given to the assessment of the GNPs' properties and the physical mechanisms underlying the laser-induced heat generation in GNPs-loaded tissues. The main techniques available for temperature measurement and the current theoretical simulation approaches predicting the therapeutic outcome are reviewed. Topical challenges in delivering safe thermal dosage are also presented with the aim to discuss the state-of-the-art and the future perspective in the field of GNPs-mediated PTT.
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Affiliation(s)
- Somayeh Asadi
- Department of Mechanical Engineering, Politecnico di Milano, Milan, Italy
| | - Leonardo Bianchi
- Department of Mechanical Engineering, Politecnico di Milano, Milan, Italy
| | - Martina De Landro
- Department of Mechanical Engineering, Politecnico di Milano, Milan, Italy
| | | | - Emiliano Schena
- Laboratory of Measurement and Biomedical Instrumentation, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Paola Saccomandi
- Department of Mechanical Engineering, Politecnico di Milano, Milan, Italy
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7
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Computed Tomography Thermography for Ablation Zone Prediction in Microwave Ablation and Cryoablation: Advantages and Challenges in an Ex Vivo Porcine Liver Model. J Comput Assist Tomogr 2020; 44:744-749. [PMID: 32842063 DOI: 10.1097/rct.0000000000001081] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The aim of this study was to investigate the diagnostic accuracy of computed tomography (CT) for the prediction of ablation zones from microwave ablation (MWA) and cryoablation (CA) in an ex vivo porcine liver model. METHODS Sequential (30 seconds) CT scans were acquired during and after MWA and CA in an ex vivo porcine liver model. We generated 120-kVp equivalent reconstructions of generic dual-energy CT data sets, and comprehensive region-of-interest measurements were statistically correlated with invasive temperature monitoring using Pearson correlation coefficient. Binary logistic regression was performed for prediction of successful ablation. RESULTS With the use of pooled data from 6 lesions in 2 separate experiments, correlation analysis of attenuation in Hounsfield units (HU) and temperature yielded r = -0.79 [confidence interval (CI), -0.85 to -0.71] for MWA and r = 0.62 (CI, 0.55 to 0.67) for CA.For MWA, there was a linear association between attenuation and temperature up to 75°C; thus, linear regression yielded a slope of -2.00 HU/°C (95% CI, -1.58 to -2.41). For CA, a linear association between attenuation and temperature was observed in the cooling phase with a slope of 2.11 HU/°C (95% CI, 1.79 to 2.58). In MWA treatment, binary logistic regression separated less than 70°C and greater than 70°C with 89.2% accuracy. Within the ice ball, temperatures above and below -20°C were distinguished with 65.3% accuracy. CONCLUSIONS Our experiments reveal several difficulties in predicting ablation zone temperature from CT attenuation. Microwave ablation leads to gas production in the tissue, which degrades the accuracy of noninvasive temperature measurement, especially at higher temperatures. In CA, CT thermometry is limited by ice ball formation, which leads to homogeneous attenuation, nearly independent of temperature. Further research is needed to define the role of CT thermography in ablation zone monitoring in liver malignancies.
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8
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Hübner F, Schreiner R, Panahi B, Vogl TJ. Evaluation of the thermal sensitivity of porcine liver in CT-guided cryoablation: an initial study. Med Phys 2020; 47:4997-5005. [PMID: 32748398 DOI: 10.1002/mp.14432] [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: 04/17/2020] [Revised: 06/19/2020] [Accepted: 07/24/2020] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To evaluate computed tomography (CT)-based thermometry in cryoablation, the thermal sensitivity of an ex-vivo porcine liver was determined in an initial study design. METHODS The CT-guided cryoablation was performed in three porcine liver samples over a period of 10 min. Fiber optic temperature probes were positioned parallel to the shaft of the cryoprobe in an axial slice orientation. During ablation, temperature measurements were performed simultaneously with CT imaging at 5 s intervals. On the CT images, the average CT number was calculated for a region of interest of 3 × 3 pixels just below the tip of each temperature probe. A linear regression analysis was performed using eleven data sets to determine the dependence of the CT number on the temperature. RESULTS With decreasing temperature, an increasing hypodense area around the tip of the cryoprobe was observed on the CT images and decreasing values of the CT number were determined. Starting at a temperature of - 40°C a linear relation between the CT number and the temperature was determined and a thermal sensitivity of 0.95 HU/°C (R2 = 0.73) was obtained. The thermal sensitivity was used to calculate color-coded temperature maps. The calculated temperature distribution corresponds quantitatively to the increasing hypodense area. CONCLUSIONS A noninvasive CT-based temperature determination during cryoablation in a normal ex vivo porcine liver is feasible. A thermal sensitivity of 0.95 HU/°C was determined by linear regression analysis. A color-coded map of the temperature distribution was presented.
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Affiliation(s)
- Frank Hübner
- Institute of Diagnostic and Interventional Radiology, University Hospital, Theodor-Stern-Kai 7, Frankfurt, 60590, Germany
| | - Roland Schreiner
- Institute of Diagnostic and Interventional Radiology, University Hospital, Theodor-Stern-Kai 7, Frankfurt, 60590, Germany
| | - Bita Panahi
- Institute of Diagnostic and Interventional Radiology, University Hospital, Theodor-Stern-Kai 7, Frankfurt, 60590, Germany
| | - Thomas Josef Vogl
- Institute of Diagnostic and Interventional Radiology, University Hospital, Theodor-Stern-Kai 7, Frankfurt, 60590, Germany
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9
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Ziv O, Goldberg SN, Nissenbaum Y, Sosna J, Weiss N, Azhari H. In vivo noninvasive three-dimensional (3D) assessment of microwave thermal ablation zone using non-contrast-enhanced x-ray CT. Med Phys 2020; 47:4721-4734. [PMID: 32745257 DOI: 10.1002/mp.14428] [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: 01/23/2020] [Revised: 07/20/2020] [Accepted: 07/22/2020] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To develop an image processing methodology for noninvasive three-dimensional (3D) quantification of microwave thermal ablation zones in vivo using x-ray computed tomography (CT) imaging without injection of a contrast enhancing material. METHODS Six microwave (MW) thermal ablation procedures were performed in three pigs. The ablations were performed with a constant heating duration of 8 min and power level of 30 W. During the procedure images from sixty 1 mm thick slices were acquired every 30 s. At the end of all ablation procedures for each pig, a contrast-enhanced scan was acquired for reference. Special algorithms for addressing challenges stemming from the 3D in vivo setup and processing the acquired images were prepared. The algorithms first rearranged the data to account for the oblique needle orientation and for breathing motion. Then, the gray level variance changes were analyzed, and optical flow analysis was applied to the treated volume in order to obtain the ablation contours and reconstruct the ablation zone in 3D. The analysis also included a special correction algorithm for eliminating artifacts caused by proximal major blood vessels and blood flow. Finally, 3D reference reconstructions from the contrast-enhanced scan were obtained for quantitative comparison. RESULTS For four ablations located >3 mm from a large blood vessel, the mean dice similarity coefficient (DSC) and the mean absolute radial discrepancy between the contours obtained from the reference contrast-enhanced images and the contours produced by the algorithm were 0.82 ± 0.03 and 1.92 ± 1.47 mm, respectively. In two cases of ablation adjacent to large blood vessels, the average DSC and discrepancy were: 0.67 ± 0.6 and 2.96 ± 2.15 mm, respectively. The addition of the special correction algorithm utilizing blood vessels mapping improved the mean DSC and the mean absolute discrepancy to 0.85 ± 0.02 and 1.19 ± 1.00 mm, respectively. CONCLUSIONS The developed algorithms provide highly accurate detailed contours in vivo (average error < 2.5 mm) and cope well with the challenges listed above. Clinical implementation of the developed methodology could potentially provide real time noninvasive 3D accurate monitoring of MW thermal ablation in-vivo, provided that the radiation dose can be reduced.
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Affiliation(s)
- Omri Ziv
- Department of Biomedical Engineering, Technion - IIT, Haifa, 32000, Israel
| | - S Nahum Goldberg
- Department of Radiology, Hadassah Medical Center, Hebrew University, Jerusalem, 91120, Israel.,Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA, 02215, USA
| | - Yitzhak Nissenbaum
- Department of Radiology, Hadassah Medical Center, Hebrew University, Jerusalem, 91120, Israel
| | - Jacob Sosna
- Department of Radiology, Hadassah Medical Center, Hebrew University, Jerusalem, 91120, Israel.,Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA, 02215, USA
| | - Noam Weiss
- Department of Biomedical Engineering, Technion - IIT, Haifa, 32000, Israel
| | - Haim Azhari
- Department of Biomedical Engineering, Technion - IIT, Haifa, 32000, Israel
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Raiko J, Koskensalo K, Sainio T. Imaging-based internal body temperature measurements: The journal Temperature toolbox. Temperature (Austin) 2020; 7:363-388. [PMID: 33251282 PMCID: PMC7678923 DOI: 10.1080/23328940.2020.1769006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/08/2020] [Accepted: 05/11/2020] [Indexed: 12/27/2022] Open
Abstract
Noninvasive imaging methods of internal body temperature are in high demand in both clinical medicine and physiological research. Thermography and thermometry can be used to assess tissue temperature during thermal therapies: ablative and hyperthermia treatments to ensure adequate temperature rise in target tissues but also to avoid collateral damage by heating healthy tissues. In research use, measurement of internal body temperature enables us the production of thermal maps on muscles, internal organs, and other tissues of interest. The most used methods for noninvasive imaging of internal body temperature are based on different parameters acquired with magnetic resonance imaging, ultrasound, computed tomography, microwave radiometry, photoacoustic imaging, and near-infrared spectroscopy. In the current review, we examine the aforementioned imaging methods, their use in estimating internal body temperature in vivo with their advantages and disadvantages, and the physical phenomena the thermography or thermometry modalities are based on.
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Affiliation(s)
- Juho Raiko
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Nutrition and Movement Sciences, Maastricht University, Maastricht, The Netherlands
| | - Kalle Koskensalo
- Department of Medical Physics, Turku University Hospital, Turku, Finland
| | - Teija Sainio
- Department of Medical Physics, Turku University Hospital, Turku, Finland
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11
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Franz PL, Wang H. Development of hypothermia measurable fiber radiometric thermometer for thermotherapy. JOURNAL OF BIOPHOTONICS 2020; 13:e201960205. [PMID: 32077211 DOI: 10.1002/jbio.201960205] [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: 12/01/2019] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 05/11/2023]
Abstract
Temperature monitoring is extremely important during thermotherapy. Fiber-optic temperature sensors are preferred because of their flexibility and immunity to electromagnetic interference. Although many types of fiber-optic sensors have been developed, clinically adopting them remains challenging. Here, we report a silica fiber-based radiometric thermometer using a low-cost extended InGaAs detector to detect black body radiation between 1.7 and 2.4 μm. For the first time, this silica fiber-based thermometer is capable of measuring temperatures down to 35°C, making it suitable for monitoring hyperthermia during surgery. In particular, the thermometer has potential for seamless integration with current silica fiber catheters, which are widely used in laser interstitial thermotherapy. The feasibility, capability and sensitivity of tracking tissue temperature variation were proved through ex vivo tissue studies. After further improvement, the technology has the potential to be translated into clinics for monitoring tissue temperature.
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Affiliation(s)
- Paris L Franz
- Department of Chemical, Paper and Biomedical Engineering, Miami University, Oxford, Ohio, USA
- Currently associated with the Department of Applied Physics, Stanford University, Stanford, California, USA
| | - Hui Wang
- Department of Chemical, Paper and Biomedical Engineering, Miami University, Oxford, Ohio, USA
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12
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Bazrafshan B, Koujan A, Hübner F, Leithäuser C, Siedow N, Vogl TJ. A thermometry software tool for monitoring laser-induced interstitial thermotherapy. ACTA ACUST UNITED AC 2019; 64:449-457. [PMID: 30243013 DOI: 10.1515/bmt-2017-0197] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 08/21/2018] [Indexed: 11/15/2022]
Abstract
The purpose of this study was to develop a thermometry software tool for temperature monitoring during laser-induced interstitial thermotherapy (LITT). C++ programming language and several libraries including DICOM Toolkit, Grassroots DICOM library, Insight Segmentation and Registration Toolkit, Visualization Toolkit and Quasar Toolkit were used. The software's graphical user interface creates windows displaying the temperature map and the coagulation extent in the tissue, determined by the magnetic resonance imaging (MRI) thermometry with the echo planar imaging sequence and a numerical simulation based on the radiation and heat transfer in biological tissues, respectively. The software was evaluated applying the MRI-guided LITT to ex vivo pig liver and simultaneously measuring the temperature through a fiber-optic thermometer as reference. Using the software, the temperature distribution determined by the MRI method was compared with the coagulation extent simulation. An agreement was shown between the MRI temperature map and the simulated coagulation extent. Furthermore, the MRI-based and simulated temperatures agreed with the measured one - a correlation coefficient of 0.9993 and 0.9996 was obtained, respectively. The precision of the MRI temperature amounted to 2.4°C. In conclusion, the software tool developed in the present study can be applied for monitoring and controlling the LITT procedure in ex vivo tissues.
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Affiliation(s)
- Babak Bazrafshan
- Universitätsklinikum Frankfurt, Institut für Diagnostische und Interventionelle Radiologie (IDIR), Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany, Phone: +49 69 6301 4793, Fax: +49 69 6301 7258
| | - Ahmad Koujan
- Universitätsklinikum Frankfurt, Institut für Diagnostische und Interventionelle Radiologie (IDIR), Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany
| | - Frank Hübner
- Universitätsklinikum Frankfurt, Institut für Diagnostische und Interventionelle Radiologie (IDIR), Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany
| | - Christian Leithäuser
- Fraunhofer-Institut für Techno- und Wirtschaftsmathematik (ITWM), Fraunhofer-Platz 1, Kaiserslautern 67663, Germany
| | - Norbert Siedow
- Fraunhofer-Institut für Techno- und Wirtschaftsmathematik (ITWM), Fraunhofer-Platz 1, Kaiserslautern 67663, Germany
| | - Thomas J Vogl
- Universitätsklinikum Frankfurt, Institut für Diagnostische und Interventionelle Radiologie (IDIR), Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany
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13
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Antonacci MA, McHugh C, Kelley M, McCallister A, Degan S, Branca RT. Direct detection of brown adipose tissue thermogenesis in UCP1-/- mice by hyperpolarized 129Xe MR thermometry. Sci Rep 2019; 9:14865. [PMID: 31619741 PMCID: PMC6795875 DOI: 10.1038/s41598-019-51483-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 10/02/2019] [Indexed: 12/19/2022] Open
Abstract
Brown adipose tissue (BAT) is a type of fat specialized in non-shivering thermogenesis. While non-shivering thermogenesis is mediated primarily by uncoupling protein 1 (UCP1), the development of the UCP1 knockout mouse has enabled the study of possible UCP1-independent non-shivering thermogenic mechanisms, whose existence has been shown so far only indirectly in white adipose tissue and still continues to be a matter of debate in BAT. In this study, by using magnetic resonance thermometry with hyperpolarized xenon, we produce the first direct evidence of UCP1-independent BAT thermogenesis in knockout mice. We found that, following adrenergic stimulation, the BAT temperature of knockout mice increases more and faster than rectal temperature. While with this study we cannot exclude or separate the physiological effect of norepinephrine on core body temperature, the fast increase of iBAT temperature seems to suggest the existence of a possible UCP1-independent thermogenic mechanism responsible for this temperature increase.
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Affiliation(s)
- Michael A Antonacci
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Physics, Saint Vincent College, Latrobe, Pennsylvania, United States of America
| | - Christian McHugh
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Michele Kelley
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Andrew McCallister
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Simone Degan
- Department of Radiology, Duke University, Durham, North Carolina, United States of America
| | - Rosa T Branca
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America.
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America.
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Giurazza F, Massaroni C, Silvestri S, Zobel BB, Schena E. Preliminary analysis of ultrasound elastography imaging-based thermometry on non-perfused ex vivo swine liver. J Ultrasound 2019; 23:69-75. [PMID: 31541360 DOI: 10.1007/s40477-019-00407-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 09/11/2019] [Indexed: 01/20/2023] Open
Abstract
AIMS Real-time monitoring of tissue temperature during percutaneous tumor ablation improves treatment efficacy, leading clinicians in adjustment of treatment settings. This study aims at assessing feasibility of ultrasound thermometry during laser ablation of biological tissue using a specific ultrasound imaging techniques based on elastography acoustic radiation force impulse (ARFI). METHODS ARFI uses high-intensity focused ultrasound pulses to generate 'radiation force' in tissue; this provokes tissue displacements trackable using correlation-based ultrasound methods: the sensitivity of shear waves velocity is able to detect temperature changes. Experiments were carried out using a Nd:YAG laser (power: 5 W) in three non-perfused ex vivo pig livers. In each organ, a thermocouple was placed close to the applicator tip (distance range 1.5-2.5 cm) used to record a reference temperature. Positioning of laser applicator and thermocouple was eco-guided. The organ was scanned by an echography system equipped with ARFI; propagation velocity was measured in a region of interest of 1 × 0.5 cm located close to thermocouple, to investigate influence of tissue temperature on shear waves velocity. RESULTS Shear wave velocity has a very low sensitivity to temperature up to 55-60 °C, and in all cases, velocity is < 5 m s-1; for temperature > 55-60 °C, velocity shows a steep increment. The system measures a value "over limit", meaning a velocity > 5 m s-1. CONCLUSIONS Ultrasound thermometry during laser ablation of biological tissue based on elastography shows an abrupt output change at temperatures > 55-60 °C. This issue can have a relevant clinical impact, considering tumor necrosis when temperature crosses 55 °C to define the boundary of damaged volume.
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Affiliation(s)
- Francesco Giurazza
- Interventional Radiology Department, Cardarelli Hospital, Via Cardarelli 9, 80100, Naples, Italy.
| | - Carlo Massaroni
- Measurement and Biomedical Instrumentation Lab, Università Campus Bio-Medico di Roma, Via A. Del Portillo 200, 00198, Rome, Italy
| | - Sergio Silvestri
- Measurement and Biomedical Instrumentation Lab, Università Campus Bio-Medico di Roma, Via A. Del Portillo 200, 00198, Rome, Italy
| | - Bruno Beomonte Zobel
- Radiology Department, Università Campus Bio-Medico di Roma, Via A. Del Portillo 200, 00198, Rome, Italy
| | - Emiliano Schena
- Measurement and Biomedical Instrumentation Lab, Università Campus Bio-Medico di Roma, Via A. Del Portillo 200, 00198, Rome, Italy
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Tan D, Mohamad NA, Wong YH, Yeong CH, Cheah PL, Sulaiman N, Abdullah BJJ, Fabell MK, Lim KS. Experimental assessment on feasibility of computed tomography-based thermometry for radiofrequency ablation on tissue equivalent polyacrylamide phantom. Int J Hyperthermia 2019; 36:554-561. [DOI: 10.1080/02656736.2019.1610800] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Daryl Tan
- School of Medicine, Faculty of Health and Medical Sciences, Taylor’s University, Subang Jaya, Selangor, Malaysia
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor’s University, Subang Jaya, Selangor, Malaysia
| | - Nurul Ashikin Mohamad
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Yin How Wong
- School of Medicine, Faculty of Health and Medical Sciences, Taylor’s University, Subang Jaya, Selangor, Malaysia
| | - Chai Hong Yeong
- School of Medicine, Faculty of Health and Medical Sciences, Taylor’s University, Subang Jaya, Selangor, Malaysia
| | - Peng Loon Cheah
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Norshazriman Sulaiman
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Basri Johan Jeet Abdullah
- School of Medicine, Faculty of Health and Medical Sciences, Taylor’s University, Subang Jaya, Selangor, Malaysia
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Mohd Kamil Fabell
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kok Sing Lim
- Photonics Research Centre, University of Malaya, Kuala Lumpur, Malaysia
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Ziv O, Goldberg SN, Nissenbaum Y, Sosna J, Weiss N, Azhari H. Optical flow and image segmentation analysis for noninvasive precise mapping of microwave thermal ablation in X-ray CT scans - ex vivo study. Int J Hyperthermia 2017; 34:744-755. [PMID: 28866952 DOI: 10.1080/02656736.2017.1375160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
PURPOSE To develop image processing algorithms for noninvasive mapping of microwave thermal ablation using X-ray CT. METHODS Ten specimens of bovine liver were subjected to microwave ablation (20-80 W, 8 min) while scanned by X-ray CT at 5 s intervals. Specimens were cut and manually traced by two observers. Two algorithms were developed and implemented to map the ablation zone. The first algorithm utilises images segmentation of Hounsfield units changes (ISHU). The second algorithm utilises radial optical flow (ROF). Algorithm sensitivity to spatiotemporal under-sampling was assessed by decreasing the acquisition rate and reducing the number of acquired projections used for image reconstruction in order to evaluate the feasibility of implementing radiation reduction techniques. RESULTS The average radial discrepancy between the ISHU and ROF contours and the manual tracing were 1.04±0.74 and 1.16±0.79mm, respectively. When diluting the input data, the ISHU algorithm retained its accuracy, ranging from 1.04 to 1.79mm. By contrast, the ROF algorithm performance became inconsistent at low acquisition rates. Both algorithms were not sensitive to projections reduction, (ISHU: 1.24±0.83mm, ROF: 1.53±1.15mm, for reduction by eight fold). Ablations near large blood vessels affected the ROF algorithm performance (1.83±1.30mm; p < 0.01), whereas ISHU performance remained the same. CONCLUSION The two suggested noninvasive ablation mapping algorithms can provide highly accurate contouring of the ablation zone at low scan rates. The ISHU algorithm may be more suitable for clinical practice as it appears more robust when radiation dose reduction strategies are employed and when the ablation zone is near large blood vessels.
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Affiliation(s)
- Omri Ziv
- a Department of Biomedical Engineering , Technion - IIT , Haifa , Israel
| | - S Nahum Goldberg
- b Department of Radiology , Hadassah Medical Center, Hebrew University , Jerusalem , Israel.,c Department of Radiology , Beth Israel Deaconess Medical Center , Boston , MA , USA
| | - Yitzhak Nissenbaum
- b Department of Radiology , Hadassah Medical Center, Hebrew University , Jerusalem , Israel
| | - Jacob Sosna
- b Department of Radiology , Hadassah Medical Center, Hebrew University , Jerusalem , Israel.,c Department of Radiology , Beth Israel Deaconess Medical Center , Boston , MA , USA
| | - Noam Weiss
- a Department of Biomedical Engineering , Technion - IIT , Haifa , Israel
| | - Haim Azhari
- a Department of Biomedical Engineering , Technion - IIT , Haifa , Israel
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Laser Ablation for Cancer: Past, Present and Future. J Funct Biomater 2017; 8:jfb8020019. [PMID: 28613248 PMCID: PMC5492000 DOI: 10.3390/jfb8020019] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 05/30/2017] [Accepted: 06/13/2017] [Indexed: 12/27/2022] Open
Abstract
Laser ablation (LA) is gaining acceptance for the treatment of tumors as an alternative to surgical resection. This paper reviews the use of lasers for ablative and surgical applications. Also reviewed are solutions aimed at improving LA outcomes: hyperthermal treatment planning tools and thermometric techniques during LA, used to guide the surgeon in the choice and adjustment of the optimal laser settings, and the potential use of nanoparticles to allow biologic selectivity of ablative treatments. Promising technical solutions and a better knowledge of laser-tissue interaction should allow LA to be used in a safe and effective manner as a cancer treatment.
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Weiss N, Goldberg SN, Nissenbaum Y, Sosna J, Azhari H. Noninvasive microwave ablation zone radii estimation using x-ray CT image analysis. Med Phys 2016; 43:4476. [PMID: 27487864 DOI: 10.1118/1.4954843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE The aims of this study were to noninvasively and automatically estimate both the radius of the ablated liver tissue and the radius encircling the treated zone, which also defines where the tissue is definitely untreated during a microwave (MW) thermal ablation procedure. METHODS Fourteen ex vivo bovine fresh liver specimens were ablated at 40 W using a 14 G microwave antenna, for durations of 3, 6, 8, and 10 min. The tissues were scanned every 5 s during the ablation using an x-ray CT scanner. In order to estimate the radius of the ablation zone, the acquired images were transformed into a polar presentation by displaying the Hounsfield units (HU) as a function of angle and radius. From this polar presentation, the average HU radial profile was analyzed at each time point and the ablation zone radius was estimated. In addition, textural analysis was applied to the original CT images. The proposed algorithm identified high entropy regions and estimated the treated zone radius per time. The estimated ablated zone radii as a function of treatment durations were compared, by means of correlation coefficient and root mean square error (RMSE) to gross pathology measurements taken immediately post-treatment from similarly ablated tissue. RESULTS Both the estimated ablation radii and the treated zone radii demonstrated strong correlation with the measured gross pathology values (R(2) ≥ 0.89 and R(2) ≥ 0.86, respectively). The automated ablation radii estimation had an average discrepancy of less than 1 mm (RMSE = 0.65 mm) from the gross pathology measured values, while the treated zone radii showed a slight overestimation of approximately 1.5 mm (RMSE = 1.6 mm). CONCLUSIONS Noninvasive monitoring of MW ablation using x-ray CT and image analysis is feasible. Automatic estimations of the ablation zone radius and the radius encompassing the treated zone that highly correlate with actual ablation measured values can be obtained. This technique can therefore potentially be used to obtain real time monitoring and improve the clinical outcome.
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Affiliation(s)
- Noam Weiss
- Department of Biomedical Engineering, Technion-IIT, Haifa 32000, Israel
| | - S Nahum Goldberg
- Department of Radiology, Hadassah Medical Center, Hebrew University, Jerusalem 91120, Israel and Department of Radiology, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115
| | - Yitzhak Nissenbaum
- Department of Radiology, Hadassah Medical Center, Hebrew University, Jerusalem 91120, Israel
| | - Jacob Sosna
- Department of Radiology, Hadassah Medical Center, Hebrew University, Jerusalem 91120, Israel and Department of Radiology, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115
| | - Haim Azhari
- Department of Biomedical Engineering, Technion-IIT, Haifa 32000, Israel
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Fiber Optic Sensors for Temperature Monitoring during Thermal Treatments: An Overview. SENSORS 2016; 16:s16071144. [PMID: 27455273 PMCID: PMC4970186 DOI: 10.3390/s16071144] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/15/2016] [Accepted: 07/18/2016] [Indexed: 01/05/2023]
Abstract
During recent decades, minimally invasive thermal treatments (i.e., Radiofrequency ablation, Laser ablation, Microwave ablation, High Intensity Focused Ultrasound ablation, and Cryo-ablation) have gained widespread recognition in the field of tumor removal. These techniques induce a localized temperature increase or decrease to remove the tumor while the surrounding healthy tissue remains intact. An accurate measurement of tissue temperature may be particularly beneficial to improve treatment outcomes, because it can be used as a clear end-point to achieve complete tumor ablation and minimize recurrence. Among the several thermometric techniques used in this field, fiber optic sensors (FOSs) have several attractive features: high flexibility and small size of both sensor and cabling, allowing insertion of FOSs within deep-seated tissue; metrological characteristics, such as accuracy (better than 1 °C), sensitivity (e.g., 10 pm·°C−1 for Fiber Bragg Gratings), and frequency response (hundreds of kHz), are adequate for this application; immunity to electromagnetic interference allows the use of FOSs during Magnetic Resonance- or Computed Tomography-guided thermal procedures. In this review the current status of the most used FOSs for temperature monitoring during thermal procedure (e.g., fiber Bragg Grating sensors; fluoroptic sensors) is presented, with emphasis placed on their working principles and metrological characteristics. The essential physics of the common ablation techniques are included to explain the advantages of using FOSs during these procedures.
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Paul J, Vogl TJ, Chacko A. Dual energy computed tomography thermometry during hepatic microwave ablation in an ex-vivo porcine model. Phys Med 2015; 31:683-91. [DOI: 10.1016/j.ejmp.2015.05.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 05/18/2015] [Accepted: 05/20/2015] [Indexed: 12/16/2022] Open
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Schena E, Saccomandi P, Giurazza F, Del Vescovo R, Mortato L, Martino M, Panzera F, Di Matteo FM, Beomonte Zobel B, Silvestri S. Monitoring of temperature increase and tissue vaporization during laser interstitial thermotherapy of ex vivo swine liver by computed tomography. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2013:378-81. [PMID: 24109703 DOI: 10.1109/embc.2013.6609516] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Laser interstitial thermotherapy (LITT) is a minimally invasive technique used to thermally destroy tumour cells. Being based on hyperthermia, LITT outcome depends on the temperature distribution inside the tissue. Recently, CT scan thermometry, based on the dependence of the CT number (HU) on tissue temperature (T) has been introduced during LITT; it is an attractive approach to monitor T because it overcomes the concerns related to the invasiveness. We performed LITT on nine ex vivo swine livers at three different laser powers, (P=1.5 W, P=3 W, P=5 W) with a constant treatment time t=200 s; HU is averaged on two ellipsoidal regions of interest (ROI) of 0.2 cm2, placed at two distances from the applicator (d=3.6 mm and d=8.7 mm); a reference ROI was placed away from the applicator (d=30 mm). The aim of this study is twofold: 1) to evaluate the effect of the T increase in terms of HU variation in ex vivo swine livers undergoing LITT; and 2) to estimate the P value for tissue vaporization. To the best of our knowledge, this is the first study focused on the HU variation in swine livers undergoing LITT at different P. The reported findings could be useful to assess the effect of LITT on the liver in terms of both T changes and tissue vaporization, with the aim to obtain an effective therapy.
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Liguori C, Frauenfelder G, Massaroni C, Saccomandi P, Giurazza F, Pitocco F, Marano R, Schena E. Emerging clinical applications of computed tomography. MEDICAL DEVICES-EVIDENCE AND RESEARCH 2015; 8:265-78. [PMID: 26089707 PMCID: PMC4467659 DOI: 10.2147/mder.s70630] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
X-ray computed tomography (CT) has recently been experiencing remarkable growth as a result of technological advances and new clinical applications. This paper reviews the essential physics of X-ray CT and its major components. Also reviewed are recent promising applications of CT, ie, CT-guided procedures, CT-based thermometry, photon-counting technology, hybrid PET-CT, use of ultrafast-high pitch scanners, and potential use of dual-energy CT for material differentiations. These promising solutions and a better knowledge of their potentialities should allow CT to be used in a safe and effective manner in several clinical applications.
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Affiliation(s)
| | | | - Carlo Massaroni
- Measurement and Biomedical Instrumentation Unit, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Paola Saccomandi
- Measurement and Biomedical Instrumentation Unit, Università Campus Bio-Medico di Roma, Rome, Italy
| | | | | | - Riccardo Marano
- Department of Radiological Sciences, Institute of Radiology, Catholic University of Rome, A Gemelli University Hospital, Rome, Italy
| | - Emiliano Schena
- Measurement and Biomedical Instrumentation Unit, Università Campus Bio-Medico di Roma, Rome, Italy
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Weiss N, Sosna J, Goldberg SN, Azhari H. Non-invasive temperature monitoring and hyperthermic injury onset detection using X-ray CT during HIFU thermal treatment in ex vivo fatty tissue. Int J Hyperthermia 2015; 30:119-25. [PMID: 24571175 DOI: 10.3109/02656736.2014.883466] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE This paper examines X-ray CT, to serve as an image-guiding thermal monitoring modality for high intensity focused ultrasound (HIFU) treatment of fatty tissues. MATERIALS AND METHODS Six ex vivo porcine fat tissue specimens were scanned by X-ray CT simultaneously with the application of HIFU. Images were acquired during both heating and post-ablation stages. The temperature at the focal zone was measured simultaneously using a thermocouple. The mean values of the Hounsfield units (HU) at the focal zone were registered and plotted as a function of temperature. RESULTS In all specimens studied, the HU versus temperature curves measured during the heating stage depicted a characteristic non-linear parabolic trajectory (R(2) > 0.87). The HU-temperature trajectory initially decreased to a minimum value at about 44.5 °C and then increased substantially as the heating progressed. The occurrence of this nadir point during the heating stage was clearly detectable. During post-ablation cooling, on the other hand, the HU increased monotonically with the decreasing temperature and depicted a clearly linear trajectory (R(2) ≥ 0.9). CONCLUSIONS Our results demonstrate that the HU-temperature curve during HIFU treatment has a characteristic parabolic trajectory for fat tissue that might potentially be utilised for thermal monitoring during HIFU ablation treatments. The clear detection of 44.5 °C, presumably marking the onset of hyperthermic injury, can be detected non-invasively as an occurrence of a minimum on the HU-time curve without any need to relate the HU directly to temperature. Such features may be helpful in monitoring and optimising HIFU thermal treatment for clinically applicable indications such as in the breast by providing a non-invasive monitoring of tissue damage.
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Affiliation(s)
- Noam Weiss
- Department of Biomedical Engineering, Technion - Israel Institute of Technology , Haifa , Israel
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Schena E, Majocchi L. Assessment of temperature measurement error and its correction during Nd:YAG laser ablation in porcine pancreas. Int J Hyperthermia 2014; 30:328-34. [DOI: 10.3109/02656736.2014.928832] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Fani F, Schena E, Saccomandi P, Silvestri S. CT-based thermometry: An overview. Int J Hyperthermia 2014; 30:219-27. [DOI: 10.3109/02656736.2014.922221] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Precht H, Leth PM, Thygesen J, Hardt-Madsen M, Nielsen B, Falk E, Egstrup K, Gerke O, Broersen A, Kitslaar PH, Dijkstra J, Lambrechtsen J. Optimisation of post mortem cardiac computed tomography compared to optical coherence tomography and histopathology – Technical note. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.jofri.2013.12.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Weiss N, Goldberg SN, Sosna J, Azhari H. Temperature–density hysteresis in X-ray CT during HIFU thermal ablation: Heating and cooling phantom study. Int J Hyperthermia 2013; 30:27-35. [DOI: 10.3109/02656736.2013.860241] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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Saccomandi P, Schena E, Silvestri S. Techniques for temperature monitoring during laser-induced thermotherapy: an overview. Int J Hyperthermia 2013; 29:609-19. [PMID: 24032415 DOI: 10.3109/02656736.2013.832411] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Laser-induced thermotherapy (LITT) is a hyperthermic procedure recently employed to treat cancer in several organs. The amount of coagulated tissue depends on the temperature distribution around the applicator, which plays a crucial role for an optimal outcome: the removal of the whole neoplastic tissue, whilst preventing damage to the surrounding healthy tissue. Although feedback concerning tissue temperature could be useful to drive the physician in the adjustment of laser settings and treatment duration, LITT is usually performed without real-time monitoring of tissue temperature. During recent decades, many thermometric techniques have been developed to be used during thermal therapies. This paper provides an overview of techniques and sensors employed for temperature measurement during tissue hyperthermia, focusing on LITT, and an investigation of their performances in this application. The paper focuses on the most promising and widespread temperature monitoring techniques, splitting them into two groups: the former includes invasive techniques based on the use of thermocouples and fibre-optic sensors; the second analyses non-invasive methods, i.e. magnetic resonance imaging-, computerised tomography- and ultrasound-based thermometry. Background information on measuring principle, medical applications, advantages and weaknesses of each method are provided and discussed.
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Affiliation(s)
- Paola Saccomandi
- Unit of Measurements and Biomedical Instrumentation, Centre for Integrated Research, University Campus Bio-Medico , Rome , Italy
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Schena E, Saccomandi P, Giurazza F, Caponero MA, Mortato L, Di Matteo FM, Panzera F, Del Vescovo R, Beomonte Zobel B, Silvestri S. Experimental assessment of CT-based thermometry during laser ablation of porcine pancreas. Phys Med Biol 2013; 58:5705-16. [DOI: 10.1088/0031-9155/58/16/5705] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Bazrafshan B, Hübner F, Farshid P, Paul J, Hammerstingl R, Vogel V, Mäntele W, Vogl TJ. Magnetic resonance temperature imaging of laser-induced thermotherapy: assessment of fast sequences in ex vivo porcine liver. Future Oncol 2013; 9:1039-50. [DOI: 10.2217/fon.13.54] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Aim: To evaluate magnetic resonance sequences for T1 and proton resonance frequency (PRF) thermometry during laser-induced thermotherapy (LITT) in liver tissue. Materials & methods: During LITT (1064 nm; 30 W; 3-cm diffuser; 2–3 min) in ex vivo porcine liver, temperature was measured (25–70°C) utilizing a fiberoptic thermometer and MRI was performed with a 1.5-T scanner through the following sequences: segmented echo planar imaging (seg-EPI) for the PRF method; fast low-angle shot (FLASH), inversion-recovery turbo FLASH (IRTF), saturation-recovery turbo FLASH (SRTF) and true-fast imaging (TRUFI) for the T1 method. Phase angle and signal amplitude (regarding PRF/T1) was recorded in regions of interest, on images under fiberoptic probe tips. Sequences’ thermal coefficients were determined by calibrating phase angle and signal amplitude against temperature and subsequently validated. Results: Coefficients of -0.0089 ± 0.0003 ppm °C-1 (seg-EPI) and -0.917 ± 0.046, -1.166 ± 0.058, -1.038 ± 0.054 and -1.443 ± 0.118°C-1 (FLASH, IRTF, SRTF and TRUFI, respectively) were obtained. Precisions of 0.71, 1.34, 2.07, 2.44 and 3.21°C and, through Bland–Altman analysis, accuracies of -0.67, 0.79, 1.65, 1.57 and 2.13°C (seg-EPI, FLASH, IRTF, SRTF and TRUFI, respectively) were determined. Conclusion: The PRF method with seg-EPI sequence is preferred for thermometry during LITT owing to higher precision and accuracy. Among T1-method sequences, FLASH showed higher accuracy and robustness.
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Affiliation(s)
- Babak Bazrafshan
- Institute for Diagnostic & Interventional Radiology, Johann Wolfgang Goethe-University Hospital, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
| | - Frank Hübner
- Institute for Diagnostic & Interventional Radiology, Johann Wolfgang Goethe-University Hospital, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany
| | - Parviz Farshid
- Institute for Diagnostic & Interventional Radiology, Johann Wolfgang Goethe-University Hospital, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany
| | - Jijo Paul
- Institute for Diagnostic & Interventional Radiology, Johann Wolfgang Goethe-University Hospital, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany
| | - Renate Hammerstingl
- Institute for Diagnostic & Interventional Radiology, Johann Wolfgang Goethe-University Hospital, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany
| | - Vitali Vogel
- Institute for Biophysics, Department of Physics, Johann Wolfgang Goethe-University, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Werner Mäntele
- Institute for Biophysics, Department of Physics, Johann Wolfgang Goethe-University, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Thomas J Vogl
- Institute for Diagnostic & Interventional Radiology, Johann Wolfgang Goethe-University Hospital, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany
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Temperature imaging of laser-induced thermotherapy (LITT) by MRI: evaluation of different sequences in phantom. Lasers Med Sci 2013; 29:173-83. [DOI: 10.1007/s10103-013-1306-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 03/11/2013] [Indexed: 12/11/2022]
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Pandeya GD, Greuter MJW, Schmidt B, Flohr T, Oudkerk M. Assessment of thermal sensitivity of CT during heating of liver: an ex vivo study. Br J Radiol 2012; 85:e661-5. [PMID: 22919016 DOI: 10.1259/bjr/23942179] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVES The purpose of this study was to assess the thermal sensitivity of CT during heating of ex-vivo animal liver. METHODS Pig liver was indirectly heated from 20 to 90 °C by passage of hot air through a plastic tube. The temperature in the heated liver was measured using calibrated thermocouples. In addition, image acquisition was performed with a multislice CT scanner before and during heating of the liver sample. The reconstructed CT images were then analysed to assess the change of CT number as a function of temperature. RESULTS During heating, a decrease in CT numbers was observed as a hypodense area on the CT images. In addition, the hypodense area extended outward from the heat source during heating. The analysis showed a linear decrease of CT number as a function of temperature. From this relationship, we derived a thermal sensitivity of CT for pig liver tissue of -0.54±0.03 HU °C(-1) with an r(2) value of 0.91. CONCLUSIONS The assessment of the thermal sensitivity of CT in ex-vivo pig liver tissue showed a linear dependency on temperature ≤90 °C. This result may be beneficial for the application of isotherms or thermal maps in CT images of liver tissue.
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Affiliation(s)
- G D Pandeya
- Department of Radiology, UMC Groningen, University of Groningen, Groningen, The Netherlands.
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