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Cencini M, Lancione M, Pasquariello R, Peretti L, Pirkl CM, Schulte RF, Buonincontri G, Arduino A, Zilberti L, Biagi L, Tosetti M. Fast high-resolution electric properties tomography using three-dimensional quantitative transient-state imaging-based water fraction estimation. NMR Biomed 2024; 37:e5039. [PMID: 37714527 DOI: 10.1002/nbm.5039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 08/18/2023] [Accepted: 08/28/2023] [Indexed: 09/17/2023]
Abstract
In this study, we aimed to develop a fast and robust high-resolution technique for clinically feasible electrical properties tomography based on water content maps (wEPT) using Quantitative Transient-state Imaging (QTI), a multiparametric transient state-based method that is similar to MR fingerprinting. Compared with the original wEPT implementation based on standard spin-echo acquisition, QTI provides robust electrical properties quantification towards B1 + inhomogeneities and full quantitative relaxometry data. To validate the proposed approach, 3D QTI data of 12 healthy volunteers were acquired on a 1.5 T scanner. QTI-provided T1 maps were used to compute water content maps of the tissues using an empirical relationship based on literature ex-vivo measurements. Assuming that electrical properties are modulated mainly by tissue water content, the water content maps were used to derive electrical conductivity and relative permittivity maps. The proposed technique was compared with a conventional phase-only Helmholtz EPT (HH-EPT) acquisition both within whole white matter, gray matter, and cerebrospinal fluid masks, and within different white and gray matter subregions. In addition, QTI-based wEPT was retrospectively applied to four multiple sclerosis adolescent and adult patients, compared with conventional contrast-weighted imaging in terms of lesion delineation, and quantitatively assessed by measuring the variation of electrical properties in lesions. Results obtained with the proposed approach agreed well with theoretical predictions and previous in vivo findings in both white and gray matter. The reconstructed maps showed greater anatomical detail and lower variability compared with standard phase-only HH-EPT. The technique can potentially improve delineation of pathology when compared with conventional contrast-weighted imaging and was able to detect significant variations in lesions with respect to normal-appearing tissues. In conclusion, QTI can reliably measure conductivity and relative permittivity of brain tissues within a short scan time, opening the way to the study of electric properties in clinical settings.
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Affiliation(s)
- Matteo Cencini
- Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, Pisa, Italy
| | | | | | | | | | | | | | | | - Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica (INRiM), Torino, Italy
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2
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Zilberti L, Arduino A, Torchio R, Zanovello U, Baruffaldi F, Sanchez-Lopez H, Bettini P, Alotto P, Chiampi M, Bottauscio O. Orthopedic implants affect the electric field induced by switching gradients in MRI. Magn Reson Med 2024; 91:398-412. [PMID: 37772634 DOI: 10.1002/mrm.29861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 08/18/2023] [Accepted: 08/20/2023] [Indexed: 09/30/2023]
Abstract
PURPOSE To investigate whether the risk of peripheral nerve stimulation increases in the presence of bulky metallic prostheses implanted in a patient's body. METHODS A computational tool was used to calculate the electric field (E-field) induced in a realistic human model due to the action of gradient fields. The calculations were performed both on the original version of the anatomical model and on a version modified through "virtual surgery" to incorporate knee, hip, and shoulder prostheses. Five exam positions within a body gradient coil and one position using a head gradient coil were simulated, subjecting the human model to the readout gradient from an EPI sequence. The induced E-field in models with and without prostheses was compared, focusing on the nerves and all other tissues (both including and excluding the bones from the analysis). RESULTS In the nerves, the most pronounced increase in the E-field (+24%) was observed around the knee implant during an abdominal MRI (Y axis readout). When extending the analysis to encompass all tissues (excluding bones), the greatest amplification (+360%) occurred around the knee implant during pelvic MRI (Z axis readout). Notable increases in E-field peaks were also identified around the shoulder and hip implants in multiple scenarios. CONCLUSION Based on the presented results, further investigations aimed at quantifying the threshold of nerve stimulation in the presence of bulky implants are desirable.
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Affiliation(s)
- Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, Italy
| | | | - Riccardo Torchio
- Department of Industrial Engineering, Università degli Studi di Padova, Padova, Italy
| | | | | | - Hector Sanchez-Lopez
- Research Center for Medical Artificial Intelligence, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China
| | - Paolo Bettini
- Department of Industrial Engineering, Università degli Studi di Padova, Padova, Italy
| | - Piergiorgio Alotto
- Department of Industrial Engineering, Università degli Studi di Padova, Padova, Italy
| | - Mario Chiampi
- Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, Italy
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Zanovello U, Fuss C, Arduino A, Bottauscio O. Efficient prediction of MRI gradient-induced heating for guiding safety testing of conductive implants. Magn Reson Med 2023; 90:2011-2018. [PMID: 37382200 DOI: 10.1002/mrm.29787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/29/2023] [Accepted: 06/15/2023] [Indexed: 06/30/2023]
Abstract
PURPOSE To propose an efficient numerical method to predict the temperature increase of an implantable medical device induced by any linearly polarized homogeneous magnetic field, according to the ISO 10974 methodology for testing of gradient-induced device heating. THEORY AND METHODS The concepts of device-specific power and temperature tensors are introduced to mathematically describe the electromagnetic and thermal anisotropic behavior of the device, from which the device heating for an arbitrary exposure direction can be predicted. The proposed method is compared to a brute-force approach based on simulations, and validated by applying it to four reference orthopedic implants with a commercial simulation software. RESULTS The proposed method requires about 5% $$ \% $$ of the time required by the brute-force approach, and 30% $$ \% $$ of the memory occupancy. The temperature increase predicted by the proposed method over a range of incident magnetic field exposures deviated from brute-force direct simulations by less than± $$ \pm $$ 0.3% $$ \% $$ . CONCLUSION The proposed method allows efficient prediction of the heating of an implantable medical device induced by any linearly polarized homogeneous magnetic field using a small fraction of the simulations required by the brute-force approach. The results can be used to predict the worst-case orientation of the gradient field, for subsequent experimental characterization according to the ISO 10974 standard.
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Affiliation(s)
- Umberto Zanovello
- Metrologia dei materiali innovativi e scienze della vita, Istituto Nazionale di Ricerca Metrologica, Torino, Italy
| | | | - Alessandro Arduino
- Metrologia dei materiali innovativi e scienze della vita, Istituto Nazionale di Ricerca Metrologica, Torino, Italy
| | - Oriano Bottauscio
- Metrologia dei materiali innovativi e scienze della vita, Istituto Nazionale di Ricerca Metrologica, Torino, Italy
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Pettenuzzo S, Arduino A, Belluzzi E, Pozzuoli A, Fontanella CG, Ruggieri P, Salomoni V, Majorana C, Berardo A. Biomechanics of Chondrocytes and Chondrons in Healthy Conditions and Osteoarthritis: A Review of the Mechanical Characterisations at the Microscale. Biomedicines 2023; 11:1942. [PMID: 37509581 PMCID: PMC10377681 DOI: 10.3390/biomedicines11071942] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 07/05/2023] [Accepted: 07/06/2023] [Indexed: 07/30/2023] Open
Abstract
Biomechanical studies are expanding across a variety of fields, from biomedicine to biomedical engineering. From the molecular to the system level, mechanical stimuli are crucial regulators of the development of organs and tissues, their growth and related processes such as remodelling, regeneration or disease. When dealing with cell mechanics, various experimental techniques have been developed to analyse the passive response of cells; however, cell variability and the extraction process, complex experimental procedures and different models and assumptions may affect the resulting mechanical properties. For these purposes, this review was aimed at collecting the available literature focused on experimental chondrocyte and chondron biomechanics with direct connection to their biochemical functions and activities, in order to point out important information regarding the planning of an experimental test or a comparison with the available results. In particular, this review highlighted (i) the most common experimental techniques used, (ii) the results and models adopted by different authors, (iii) a critical perspective on features that could affect the results and finally (iv) the quantification of structural and mechanical changes due to a degenerative pathology such as osteoarthritis.
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Affiliation(s)
- Sofia Pettenuzzo
- Department of Civil, Environmental and Architectural Engineering, University of Padova, 35131 Padova, Italy
| | - Alessandro Arduino
- Department of Civil, Environmental and Architectural Engineering, University of Padova, 35131 Padova, Italy
| | - Elisa Belluzzi
- Musculoskeletal Pathology and Oncology Laboratory, Department of Surgery, Oncology and Gastroenterology, University of Padova (DiSCOG), Via Giustiniani 3, 35128 Padova, Italy
- Orthopedics and Orthopedic Oncology, Department of Surgery, Oncology and Gastroenterology, University of Padova (DiSCOG), 35128 Padova, Italy
| | - Assunta Pozzuoli
- Musculoskeletal Pathology and Oncology Laboratory, Department of Surgery, Oncology and Gastroenterology, University of Padova (DiSCOG), Via Giustiniani 3, 35128 Padova, Italy
- Orthopedics and Orthopedic Oncology, Department of Surgery, Oncology and Gastroenterology, University of Padova (DiSCOG), 35128 Padova, Italy
| | | | - Pietro Ruggieri
- Orthopedics and Orthopedic Oncology, Department of Surgery, Oncology and Gastroenterology, University of Padova (DiSCOG), 35128 Padova, Italy
| | - Valentina Salomoni
- Department of Civil, Environmental and Architectural Engineering, University of Padova, 35131 Padova, Italy
- Department of Management and Engineering (DTG), Stradella S. Nicola 3, 36100 Vicenza, Italy
| | - Carmelo Majorana
- Department of Civil, Environmental and Architectural Engineering, University of Padova, 35131 Padova, Italy
| | - Alice Berardo
- Department of Civil, Environmental and Architectural Engineering, University of Padova, 35131 Padova, Italy
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
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Arduino A, Pennecchi F, Katscher U, Cox M, Zilberti L. Repeatability and Reproducibility Uncertainty in Magnetic Resonance-Based Electric Properties Tomography of a Homogeneous Phantom. Tomography 2023; 9:420-435. [PMID: 36828386 PMCID: PMC9961522 DOI: 10.3390/tomography9010034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 02/10/2023] [Accepted: 02/14/2023] [Indexed: 02/19/2023] Open
Abstract
Uncertainty assessment is a fundamental step in quantitative magnetic resonance imaging because it makes comparable, in a strict metrological sense, the results of different scans, for example during a longitudinal study. Magnetic resonance-based electric properties tomography (EPT) is a quantitative imaging technique that retrieves, non-invasively, a map of the electric properties inside a human body. Although EPT has been used in some early clinical studies, a rigorous experimental assessment of the associated uncertainty has not yet been performed. This paper aims at evaluating the repeatability and reproducibility uncertainties in phase-based Helmholtz-EPT applied on homogeneous phantom data acquired with a clinical 3 T scanner. The law of propagation of uncertainty is used to evaluate the uncertainty in the estimated conductivity values starting from the uncertainty in the acquired scans, which is quantified through a robust James-Stein shrinkage estimator to deal with the dimensionality of the problem. Repeatable errors are detected in the estimated conductivity maps and are quantified for various values of the tunable parameters of the EPT implementation. The spatial dispersion of the estimated electric conductivity maps is found to be a good approximation of the reproducibility uncertainty, evaluated by changing the position of the phantom after each scan. The results underpin the use of the average conductivity (calculated by weighting the local conductivity values by their uncertainty and taking into account the spatial correlation) as an estimate of the conductivity of the homogeneous phantom.
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Affiliation(s)
- Alessandro Arduino
- Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy
- Correspondence:
| | - Francesca Pennecchi
- Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy
| | | | - Maurice Cox
- National Physical Laboratory, Teddington TW11 0LW, UK
| | - Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy
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Bottauscio O, Arduino A, Chiampi M, Zilberti L. Simplified modeling of implanted medical devices with metallic filamentary closed loops exposed to low or medium frequency magnetic fields. Comput Methods Programs Biomed 2023; 229:107316. [PMID: 36566651 DOI: 10.1016/j.cmpb.2022.107316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 12/12/2022] [Accepted: 12/16/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND OBJECTIVES Electric currents are induced in implanted medical devices with metallic filamentary closed loops (e.g., fixation grids, stents) when exposed to time varying magnetic fields, as those generated during certain diagnostic and therapeutic biomedical treatments. A simplified methodology to efficiently compute these currents, to estimate the altered electromagnetic field distribution in the biological tissues and to assess the consequent biological effects is proposed for low or medium frequency fields. METHODS The proposed methodology is based on decoupling the handling of the filamentary wire and the anatomical body. To do this, a circuital solution is adopted to study the metallic filamentary implant and this solution is inserted in the electromagnetic field solution involving the biological tissues. The Joule losses computed in the implant are then used as a forcing term for the thermal problem defined by the bioheat Pennes' equation. The methodology is validated against a model problem, where a reference solution is available. RESULTS The proposed simplified methodology is proved to be in good agreement with solutions provided by alternative approaches. In particular, errors in the amplitude of the currents induced in the wires result to be always lower than 3%. After the validation, the methodology is applied to check the interactions between the magnetic field generated by different biomedical devices and a skull grid, which represents a complex filamentary wire implant. CONCLUSIONS The proposed simplified methodology, suitable to be applied to closed loop wires in the low to intermediate frequency range, is found to be sufficiently accurate and easy to apply in realistic exposure scenarios. This modeling tool allows analyzing different types of small implants, from coronary and biliary duct stents to orthopedic grids, under a variety of exposure scenarios.
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Affiliation(s)
- Oriano Bottauscio
- Istituto Nazionale di Ricerca Metrologica (INRiM), Strada Delle Cacce 91, 10135 Torino, Italy.
| | - Alessandro Arduino
- Istituto Nazionale di Ricerca Metrologica (INRiM), Strada Delle Cacce 91, 10135 Torino, Italy
| | - Mario Chiampi
- Istituto Nazionale di Ricerca Metrologica (INRiM), Strada Delle Cacce 91, 10135 Torino, Italy
| | - Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica (INRiM), Strada Delle Cacce 91, 10135 Torino, Italy
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Bottauscio O, Rubia-Rodríguez I, Arduino A, Zilberti L, Chiampi M, Ortega D. Heating of metallic biliary stents during magnetic hyperthermia of patients with pancreatic ductal adenocarcinoma: an in silico study. Int J Hyperthermia 2022; 39:1222-1232. [DOI: 10.1080/02656736.2022.2121863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
Affiliation(s)
| | | | | | - Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica (INRIM), Turin, Italy
| | - Mario Chiampi
- Istituto Nazionale di Ricerca Metrologica (INRIM), Turin, Italy
| | - Daniel Ortega
- IMDEA Nanoscience, Madrid, Spain
- Condensed Matter Physics Department, University of Cádiz, Cádiz, Spain
- Institute of Research and Innovation in Biomedical Sciences of Cádiz (INiBICA), University of Cádiz, Cádiz, Spain
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8
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Arduino A, Baruffaldi F, Bottauscio O, Chiampi M, Martinez JA, Zanovello U, Zilberti L. Computational dosimetry in MRI in presence of hip, knee or shoulder implants: do we need accurate surgery models? Phys Med Biol 2022; 67. [PMID: 36541561 DOI: 10.1088/1361-6560/aca5e6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 11/24/2022] [Indexed: 11/27/2022]
Abstract
Objective.To quantify the effects of different levels of realism in the description of the anatomy around hip, knee or shoulder implants when simulating, numerically, radiofrequency and gradient-induced heating in magnetic resonance imaging. This quantification is needed to define how precise the digital human model modified with the implant should be to get realistic dosimetric assessments.Approach. The analysis is based on a large number of numerical simulations where four 'levels of realism' have been adopted in modelling human bodies carrying orthopaedic implants.Main results. Results show that the quantification of the heating due to switched gradient fields does not strictly require a detailed local anatomical description when preparing the digital human model carrying an implant. In this case, a simple overlapping of the implant CAD with the body anatomy is sufficient to provide a quite good and conservative estimation of the heating. On the contrary, the evaluation of the electromagnetic field distribution and heating caused by the radiofrequency field requires an accurate description of the tissues around the prosthesis.Significance. The results of this paper provide hints for selecting the 'level of realism' in the definition of the anatomical models with embedded passive implants when performing simulations that should reproduce, as closely as possible, thein vivoscenarios of patients carrying orthopaedic implants.
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Affiliation(s)
| | | | | | - Mario Chiampi
- Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, Italy
| | | | | | - Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, Italy
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9
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Arduino A, Bottauscio O, Chiampi M, Zanovello U, Zilberti L. A contribution to MRI safety testing related to gradient-induced heating of medical devices. Magn Reson Med 2022; 88:930-944. [PMID: 35344605 PMCID: PMC9314691 DOI: 10.1002/mrm.29235] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 01/22/2022] [Accepted: 02/24/2022] [Indexed: 12/26/2022]
Abstract
PURPOSE To theoretically investigate the feasibility of a novel procedure for testing the MRI gradient-induced heating of medical devices and translating the results into clinical practice. METHODS The concept of index of stress is introduced by decoupling the time waveform characteristics of the gradient field signals from the field spatial distribution within an MRI scanner. This index is also extended to consider the anisotropy of complex bulky metallic implants. Merits and drawbacks of the proposed index of stress are investigated through virtual experiments. In particular, the values of the index of stress evaluated for realistic orthopedic implants placed within an ASTM phantom are compared with accurate heating simulations performed with 2 anatomic body models (a man and a woman) implanted through a virtual surgery procedure. RESULTS The manipulation of the proposed index of stress allows to identify regions within the MRI bore where the implant could affect the safety of the examinations. Furthermore, the conducted analysis shows that the power dissipated into the implant by the induced eddy currents is a dosimetric quantity that estimates well the maximum temperature increase in the tissues surrounding the implant. CONCLUSION The results support the adoption of an anisotropic index of stress to regulate the gradient-induced heating of geometrically complex implants. They also pave the way for a laboratory characterization of the implants based on electrical measurements, rather than on thermal measurements. The next step will be to set up a standardized experimental procedure to evaluate the index of stress associated with an implant.
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Affiliation(s)
| | | | - Mario Chiampi
- Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, Italy
| | | | - Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, Italy
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10
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Torchio R, Arduino A, Zilberti L, Bottauscio O. A fast tool for the parametric analysis of human body exposed to LF electromagnetic fields in biomedical applications. Comput Methods Programs Biomed 2022; 214:106543. [PMID: 34861616 DOI: 10.1016/j.cmpb.2021.106543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 11/02/2021] [Accepted: 11/15/2021] [Indexed: 06/13/2023]
Abstract
A numerical procedure for analyzing electromagnetic (EM) fields interactions with biological tissues is presented. The proposed approach aims at drastically reducing the computational burden required by the repeated solution of large scale problems involving the interaction of the human body with EM fields, such as in the study of the time evolution of EM fields, uncertainty quantification, and inverse problems. The proposed volume integral equation (VIE), focused on low frequency applications, is a system of integral equations in terms of current density and scalar potential in the biological tissues excited by EM fields and/or electrodes connected to the human body. The proposed formulation requires the voxelization of the human body and takes advantage of the regularity of such discretization by speeding-up the computational procedure. Moreover, it exploits recent advancements in the solution of VIE by means of iterative preconditioned solvers and ad hoc parametric Model Order Reduction techniques. The efficiency of the proposed tool is demonstrated by applying it to a couple of realistic model problems: the assessment of the peripheral nerve stimulation, performed in terms of evaluation of the induced electric field, due to the gradient coils of a magnetic resonance imaging scanner during a clinical examination and the assessment of the exposure to environmental fields at 50 Hz of live-line workers with uncertain properties of the biological tissues. Thanks to the proposed method, uncertainty quantification analyses and time domain simulations are possible even for large scale problems and they can be performed on standard computers and reasonable computation time. Sample implementation of the method is made publicly available at https://github.com/UniPD-DII-ETCOMP/BioMOR.
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Affiliation(s)
- Riccardo Torchio
- Department of Industrial Engineering, Università degli Studi di Padova, Padova 35131, Italy.
| | | | - Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica, Torino 10135, Italy
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11
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Arduino A, Pettenuzzo S, Berardo A, Salomoni VA, Majorana C, Carniel EL. A Continuum-Tensegrity Computational Model for Chondrocyte Biomechanics in AFM Indentation and Micropipette Aspiration. Ann Biomed Eng 2022; 50:1911-1922. [PMID: 35879583 PMCID: PMC9794536 DOI: 10.1007/s10439-022-03011-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 07/05/2022] [Indexed: 12/31/2022]
Abstract
Mechanical stimuli are fundamental in the development of organs and tissues, their growth, regeneration or disease. They influence the biochemical signals produced by the cells, and, consequently, the development and spreading of a disease. Moreover, tumour cells are usually characterized by a decrease in the cell mechanical properties that may be directly linked to their metastatic potential. Thus, recently, the experimental and computational study of cell biomechanics is facing a growing interest. Various experimental approaches have been implemented to describe the passive response of cells; however, cell variability and complex experimental procedures may affect the obtained mechanical properties. For this reason, in-silico computational models have been developed through the years, to overcome such limitations, while proposing valuable tools to understand cell mechanical behaviour. This being the case, we propose a combined continuous-tensegrity finite element (FE) model to analyse the mechanical response of a cell and its subcomponents, observing how every part contributes to the overall mechanical behaviour. We modelled both Atomic Force Microscopy (AFM) indentation and micropipette aspiration techniques, as common mechanical tests for cells and elucidated also the role of cell cytoplasm and cytoskeleton in the global cell mechanical response.
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Affiliation(s)
- Alessandro Arduino
- Department of Civil, Environmental and Architectural Engineering, University of Padova, Padua, Italy
| | - Sofia Pettenuzzo
- Department of Civil, Environmental and Architectural Engineering, University of Padova, Padua, Italy
| | - Alice Berardo
- Department of Civil, Environmental and Architectural Engineering, University of Padova, Padua, Italy.
- Department of Biomedical Sciences, University of Padova, Padua, Italy.
| | | | - Carmelo Majorana
- Department of Civil, Environmental and Architectural Engineering, University of Padova, Padua, Italy
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Wooldridge J, Arduino A, Zilberti L, Zanovello U, Chiampi M, Clementi V, Bottauscio O. Gradient coil and radiofrequency induced heating of orthopaedic implants in MRI: influencing factors. Phys Med Biol 2021; 66. [PMID: 34847533 DOI: 10.1088/1361-6560/ac3eab] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 11/30/2021] [Indexed: 11/12/2022]
Abstract
Patients with implanted orthopaedic devices represent a growing number of subjects undergoing magnetic resonance imaging (MRI) scans each year. MRI safety labelling is required for all implants under the EU Medical Device Regulations to ensure regulatory compliance, with each device assessed through standardised testing procedures. In this paper, we employ parametric studies to assess a range of clinically relevant factors that cause tissue heating, performing simulations with both radiofrequency (RF) and gradient coil (GC) switching fields, the latter of which is often overlooked in the literature. A series of 'worst-case' scenarios for both types of excitation field is discussed. In the case of GC fields, large volume implants and large plate areas with the field orientated perpendicular to the plane cause the highest heating levels, along with sequences with high rates of field switching. Implant heating from RF fields is driven primarily from the 'antenna effect', with thin, linear implants of resonant length resulting in the highest temperature rises. In this work, we show that simplifications may be made to the field sequence and in some cases the device geometry without significantly compromising the accuracy of the simulation results, enabling the possibility for generic estimates of the implant heating for orthopaedic device manufacturers and opportunities to simplify the safety compliance process.
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Affiliation(s)
- J Wooldridge
- National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW, United Kingdom
| | - A Arduino
- Istituto Nazionale di Ricerca Metrologica, Str. delle Cacce, 91, I-10135 Torino TO, Italy
| | - L Zilberti
- Istituto Nazionale di Ricerca Metrologica, Str. delle Cacce, 91, I-10135 Torino TO, Italy
| | - U Zanovello
- Istituto Nazionale di Ricerca Metrologica, Str. delle Cacce, 91, I-10135 Torino TO, Italy
| | - M Chiampi
- Istituto Nazionale di Ricerca Metrologica, Str. delle Cacce, 91, I-10135 Torino TO, Italy
| | - V Clementi
- IRCCS Istituto Ortopedico Rizzoli, Laboratorio di Tecnologia Medica, Via di Barbiano 1/10, I-40136 Bologna, Italy
| | - O Bottauscio
- Istituto Nazionale di Ricerca Metrologica, Str. delle Cacce, 91, I-10135 Torino TO, Italy
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Clementi V, Zanovello U, Arduino A, Ancarani C, Bordini B, Bottauscio O, Chiampi M, Zilberti L, Baruffaldi F. MRI and metallic implants: heating risk by radiofrequency and switching gradient fields. Phys Med 2021. [DOI: 10.1016/s1120-1797(22)00289-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Arduino A, Bottauscio O, Chiampi M, Zanovello U, Zilberti L. Heating of metallic implants in MRI: the European project MIMAS. Phys Med 2021. [DOI: 10.1016/s1120-1797(22)00557-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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15
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Rubia-Rodríguez I, Zilberti L, Arduino A, Bottauscio O, Chiampi M, Ortega D. In silico assessment of collateral eddy current heating in biocompatible implants subjected to magnetic hyperthermia treatments. Int J Hyperthermia 2021; 38:846-861. [PMID: 34074196 DOI: 10.1080/02656736.2021.1909758] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Purpose: Bearing partially or fully metallic passive implants represents an exclusion criterion for patients undergoing a magnetic hyperthermia procedure, but there are no specific studies backing this restrictive decision. This work assesses how the secondary magnetic field generated at the surface of two common types of prostheses affects the safety and efficiency of magnetic hyperthermia treatments of localized tumors. The paper also proposes the combination of a multi-criteria decision analysis and a graphical representation of calculated data as an initial screening during the preclinical risk assessment for each patient.Materials and methods: Heating of a hip joint and a dental implant during the treatment of prostate, colorectal and head and neck tumors have been assessed considering different external field conditions and exposure times. The Maxwell equations including the secondary field produced by metallic prostheses have been solved numerically in a discretized computable human model. The heat exchange problem has been solved through a modified version of the Pennes' bioheat equation assuming a temperature dependency of blood perfusion and metabolic heat, i.e. thermorregulation. The degree of risk has been assessed using a risk index with parameters coming from custom graphs plotting the specific absorption rate (SAR) vs temperature increase, and coefficients derived from a multi-criteria decision analysis performed following the MACBETH approach.Results: The comparison of two common biomaterials for passive implants - Ti6Al4V and CoCrMo - shows that both specific absorption rate (SAR) and local temperature increase are found to be higher for the hip prosthesis made by Ti6Al4V despite its lower electrical and thermal conductivity. By tracking the time evolution of temperature upon field application, it has been established that there is a 30 s delay between the time point for which the thermal equilibrium is reached at prostheses and tissues. Likewise, damage may appear in those tissues adjacent to the prostheses at initial stages of treatment, since recommended thermal thresholds are soon surpassed for higher field intensities. However, it has also been found that under some operational conditions the typical safety rule of staying below or attain a maximum temperature increase or SAR value is met.Conclusion: The current exclusion criterion for implant-bearing patients in magnetic hyperthermia should be revised, since it may be too restrictive for a range of the typical field conditions used. Systematic in silico treatment planning using the proposed methodology after a well-focused diagnostic procedure can aid the clinical staff to find the appropriate limits for a safe treatment window.
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Affiliation(s)
| | - Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica (INRIM), Turin, Italy
| | | | | | - Mario Chiampi
- Istituto Nazionale di Ricerca Metrologica (INRIM), Turin, Italy
| | - Daniel Ortega
- IMDEA Nanoscience, Madrid, Spain.,Institute of Research and Innovation in Biomedical Sciences of the Province of Cádiz (INiBICA), University of Cádiz, Cádiz, Spain.,Condensed Matter Physics department, University of Cádiz, Cádiz, Spain
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16
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Fontanella CG, Arduino A, Toniolo I, Zampieri C, Bortolan L, Carniel EL. Computational methods for the investigation of ski boots ergonomics. Sports Eng 2021. [DOI: 10.1007/s12283-021-00352-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AbstractSki boots are known to cause vasoconstriction in the wearer’s lower limbs and, thus, cause a “cold leg” phenomenon. To address this problem, this work provides a computational framework for analysing interactions between the ski boot and the lower limb. The geometry of the lower limb was derived from magnetic resonance imaging and computed tomography techniques and anthropometric data. The geometry of the ski boot shell was obtained by means of three-dimensional computer aided design models from a manufacturer. Concerning the ski boot liner, laser scanning techniques were implemented to capture the geometry of each layer. The mechanical models of the ski boot and the lower limb were identified and validated by means of coupled experimental investigations and computational analyses. The computational models were exploited to simulate the buckling process and to investigate interaction phenomena between the boot and the lower limb. Similarly, experimental activities were performed to further analyse the buckling phenomena. The obtained computational and experimental results were compared regarding both interaction pressure and displacements between the buckle and the corresponding buckle hooks. These comparisons provided reasonable agreement (mean value of discrepancy between the model and mean experimental results in the tibial region: 20%), underlining the model’s capability to correctly interpret results from experimental measurements. Results identified the critical areas of the leg, such as the tibial region, the calcaneal region of the foot and the anterior sole, which may suffer the most due to the hydrostatic pressure and compressive strain exerted on them. The results highlight that computational methods allow investigation of the interaction phenomena between the lower leg and ski boot, potentially providing an effective framework for a more comfortable and ergonomic design of ski boots.
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17
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Arduino A, Zanovello U, Hand J, Zilberti L, Brühl R, Chiampi M, Bottauscio O. Heating of hip joint implants in MRI: The combined effect of RF and switched-gradient fields. Magn Reson Med 2021; 85:3447-3462. [PMID: 33483979 PMCID: PMC7986841 DOI: 10.1002/mrm.28666] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/09/2020] [Accepted: 12/09/2020] [Indexed: 12/20/2022]
Abstract
PURPOSE To investigate how the simultaneous exposure to gradient and RF fields affects the temperature rise in patients with a metallic hip prosthesis during an MRI session. METHODS In silico analysis was performed with an anatomically realistic human model with CoCrMo hip implant in 12 imaging positions. The analysis was performed at 1.5 T and 3 T, considering four clinical sequences: turbo spin-echo, EPI, gradient-echo, and true fast imaging sequence with steady precession. The exposure to gradient and RF fields was evaluated separately and superposed, by adopting an ad hoc computational algorithm. Temperature increase within the body, rather than specific absorption rate, was used as a safety metric. RESULTS With the exception of gradient-echo, all investigated sequences produced temperature increases higher than 1 K after 360 seconds, at least for one body position. In general, RF-induced heating dominates the turbo spin-echo sequence, whereas gradient-induced heating prevails with EPI; the situation with fast imaging sequence with steady precession is more diversified. The RF effects are enhanced when the implant is within the RF coil, whereas the effects of gradient fields are maximized if the prosthesis is outside the imaging region. Cases for which temperature-increase thresholds were exceeded were identified, together with the corresponding amount of tissue mass involved and the exposure time needed to reach these limits. CONCLUSION The analysis confirms that risky situations may occur when a patient carrying a hip implant undergoes an MRI exam and that, in some cases, the gradient field heating may be significant. In general, exclusion criteria only based on whole-body specific absorption rate may not be sufficient to ensure patients' safety.
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Affiliation(s)
| | | | - Jeff Hand
- School of Biomedical Engineering and Imaging SciencesKing’s College LondonLondonUnited Kingdom
| | - Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica (INRIM)TorinoItaly
| | - Rüdiger Brühl
- Physikalisch‐Technische BundesanstaltBraunschweig and BerlinGermany
| | - Mario Chiampi
- Istituto Nazionale di Ricerca Metrologica (INRIM)TorinoItaly
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18
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Battaglino B, Arduino A, Pagliano C, Sforza E, Bertucco A. Optimization of Light and Nutrients Supply to Stabilize Long-Term Industrial Cultivation of Metabolically Engineered Cyanobacteria: A Model-Based Analysis. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.0c04887] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Beatrice Battaglino
- BioSolar Lab, Applied Science and Technology Department, Politecnico di Torino, Environment Park, Via Livorno 60, 10144 Torino, Italy
| | - Alessandro Arduino
- Istituto Nazionale di Ricerca Metrologica (INRIM), Strada delle Cacce 91, 10135 Torino, Italy
| | - Cristina Pagliano
- BioSolar Lab, Applied Science and Technology Department, Politecnico di Torino, Environment Park, Via Livorno 60, 10144 Torino, Italy
| | - Eleonora Sforza
- Department of Industrial Engineering, Università di Padova, Via Marzolo 9, 35131 Padova, Italy
| | - Alberto Bertucco
- Department of Industrial Engineering, Università di Padova, Via Marzolo 9, 35131 Padova, Italy
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19
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Battaglino B, Arduino A, Pagliano C. Mathematical modeling for the design of evolution experiments to study the genetic instability of metabolically engineered photosynthetic microorganisms. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.102093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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20
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Zilberti L, Zanovello U, Arduino A, Bottauscio O, Chiampi M. RF-induced heating of metallic implants simulated as PEC: Is there something missing? Magn Reson Med 2020; 85:583-586. [PMID: 32936504 DOI: 10.1002/mrm.28512] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 01/06/2023]
Affiliation(s)
- Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica, Torino, Italy
| | | | | | | | - Mario Chiampi
- Istituto Nazionale di Ricerca Metrologica, Torino, Italy
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21
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Fontanella CG, Macchi V, Porzionato A, Arduino A, Fotso Fongang JV, De Caro R, Natali AN, Carniel EL. A numerical investigation of the infrapatellar fat pad. Proc Inst Mech Eng H 2020; 234:1113-1121. [PMID: 32650701 DOI: 10.1177/0954411920940839] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The infrapatellar fat pad is an adipose tissue in the knee that facilitates the distribution of synovial fluid and absorbs impulsive actions generated through the joint. The correlation between morphological configuration and mechanical properties is analyzed by a computational approach. The microscopic anatomy of the infrapatellar fat pad is studied aiming to measure the dimension of adipose lobules and the thickness of connective septa. Results from histomorphometric investigations show that the infrapatellar fat pad is an inhomogeneous tissue, constituted by large lobules in the superficial part and smaller lobules in the deepest one. Finite element models of the infrapatellar fat pad are developed. The first model considers the inhomogeneous conformation of the infrapatellar fat pad, composed of micro- and macro-chambers, while the second model considers a homogeneous distribution of adipose lobules with similar dimensions. Computational analyses are performed considering the static standing configuration and the passive flexion-extension movement. The computational results allow us to identify the different stress and strain fields within the tissue and to appreciate the variation of the mechanical performance of the overall system considering the distribution of adipose lobules. Results show that the distribution of adipose lobules in macro- and micro-chambers allows major deformation of the infrapatellar fat pad, decreasing the stress inside the tissues.
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Affiliation(s)
- Chiara Giulia Fontanella
- Department of Industrial Engineering, University of Padova, Padova, Italy.,Centre for Mechanics of Biological Materials, University of Padova, Padova, Italy
| | - Veronica Macchi
- Centre for Mechanics of Biological Materials, University of Padova, Padova, Italy.,Institute of Human Anatomy, Department of Neuroscience, University of Padova, Padova, Italy
| | - Andrea Porzionato
- Centre for Mechanics of Biological Materials, University of Padova, Padova, Italy.,Institute of Human Anatomy, Department of Neuroscience, University of Padova, Padova, Italy
| | - Alessandro Arduino
- Department of Civil, Environmental and Architectural Engineering, University of Padova, Padova, Italy
| | | | - Raffaele De Caro
- Centre for Mechanics of Biological Materials, University of Padova, Padova, Italy.,Institute of Human Anatomy, Department of Neuroscience, University of Padova, Padova, Italy
| | - Arturo Nicola Natali
- Department of Industrial Engineering, University of Padova, Padova, Italy.,Centre for Mechanics of Biological Materials, University of Padova, Padova, Italy
| | - Emanuele Luigi Carniel
- Department of Industrial Engineering, University of Padova, Padova, Italy.,Centre for Mechanics of Biological Materials, University of Padova, Padova, Italy
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22
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Bottauscio O, Arduino A, Bavastro D, Capra D, Guarneri A, Parizia AA, Zilberti L. Exposure of Live-Line Workers to Magnetic Fields: A Dosimetric Analysis. Int J Environ Res Public Health 2020; 17:ijerph17072429. [PMID: 32252473 PMCID: PMC7177450 DOI: 10.3390/ijerph17072429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 03/30/2020] [Accepted: 03/31/2020] [Indexed: 12/02/2022]
Abstract
In this paper the authors present the results of a dosimetric analysis related to the exposure of live-line workers to the magnetic fields generated by high voltage overhead lines and substations. The study extends the work published by Dawson et al. in 2002, considering more evolved anatomical models nowadays available, the new reference limits given by the 2013/35/EU Directive, and a new methodology, based on the intercomparison of two alternative solvers and the use of data filtering. Moreover, additional exposure scenarios are here considered with respect to the studies already available in literature. The results show that for the exposure scenario of high voltage live line works with bare hand method, in any analyzed position, the exposure limits for the tissues of the central nervous system, as well as for all other tissues, are never exceeded, despite in some cases the action levels are exceeded. For the exposure of workers in substations near 220 kV and 380 kV line trap coils exposure is compliant with the regulatory limits if the current flowing through the line trap does not exceed the value of 1000 A. Finally, for the exposure of workers in substations near cable connections, electric field values induced in the body are always lower than regulatory limits with a phase current value equal to 1600 A r.m.s.
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Affiliation(s)
- Oriano Bottauscio
- Istituto Nazionale di Ricerca Metrologica, 10135 Torino, Italy; (A.A.); (L.Z.)
- Correspondence:
| | - Alessandro Arduino
- Istituto Nazionale di Ricerca Metrologica, 10135 Torino, Italy; (A.A.); (L.Z.)
| | - Davide Bavastro
- Terna Rete Italia S.p.A., 00156 Roma, Italy; (D.B.); (A.A.P.)
| | | | | | | | - Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica, 10135 Torino, Italy; (A.A.); (L.Z.)
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23
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Arduino A, Bottauscio O, Brühl R, Chiampi M, Zilberti L. In silico evaluation of the thermal stress induced by MRI switched gradient fields in patients with metallic hip implant. ACTA ACUST UNITED AC 2019; 64:245006. [DOI: 10.1088/1361-6560/ab5428] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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24
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Allegra S, Cusato J, De Francia S, Arduino A, Longo F, Pirro E, Massano D, De Nicolò A, Piga A, D'Avolio A. Role of CYP24A1, VDR and GC gene polymorphisms on deferasirox pharmacokinetics and clinical outcomes. Pharmacogenomics J 2017; 18:506-515. [PMID: 29160302 DOI: 10.1038/tpj.2017.43] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 06/01/2017] [Accepted: 08/04/2017] [Indexed: 02/06/2023]
Abstract
β-Thalassemia patients develop deficiency in vitamin D absorption and liver hydroxylation, resulting in extremely low calcitriol levels. We explored the role of single-nucleotide polymorphisms (SNPs) involved in vitamin D metabolism, transport and activity on deferasirox pharmacokinetics and outcomes (effectiveness trough levels (Ctrough) and the area under the curve (AUC) cutoffs of 20 μg ml-1 and 360 μg ml-1 h-1, respectively; nonresponse AUC limit of 250 μg ml-1 h-1). Ninety-nine β-thalassemic patients were enrolled. Drug plasma Ctrough and AUC were measured by the high-performance liquid chromatography system coupled with an ultraviolet determination method. Allelic discrimination for VDR, CYP24A1, CYP27B1 and GC gene SNPs was performed by real-time PCR. CYP24A1 22776 TT significantly influenced Cmin and negatively predicted it in regression analysis. CYP24A1 3999 CC was associated with Ctrough and Cmin and was a negative predictor of Tmax, whereas CYP24A1 8620 GG seemed to have a role in Ctrough, AUC, t1/2 and Cmin, and was an AUC negative predictor factor. Considering treatment outcome, Cdx2 and GC 1296 were retained in regression analysis as AUC efficacy cutoff negative predictors.
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Affiliation(s)
- S Allegra
- Unit of Infectious Diseases, University of Turin, Department of Medical Sciences, Amedeo di Savoia Hospital, Turin, Italy
| | - J Cusato
- Unit of Infectious Diseases, University of Turin, Department of Medical Sciences, Amedeo di Savoia Hospital, Turin, Italy
| | - S De Francia
- Department of Biological and Clinical Sciences, University of Turin, S. Luigi Gonzaga Hospital, Orbassano, Italy
| | - A Arduino
- Unit of Infectious Diseases, University of Turin, Department of Medical Sciences, Amedeo di Savoia Hospital, Turin, Italy
| | - F Longo
- Department of Paediatrics, Centre for Microcitemie, University of Turin, S. Luigi Gonzaga Hospital, Orbassano, Italy
| | - E Pirro
- Department of Biological and Clinical Sciences, University of Turin, S. Luigi Gonzaga Hospital, Orbassano, Italy
| | - D Massano
- Department of Paediatrics, Centre for Microcitemie, University of Turin, S. Luigi Gonzaga Hospital, Orbassano, Italy
| | - A De Nicolò
- Unit of Infectious Diseases, University of Turin, Department of Medical Sciences, Amedeo di Savoia Hospital, Turin, Italy
| | - A Piga
- Department of Paediatrics, Centre for Microcitemie, University of Turin, S. Luigi Gonzaga Hospital, Orbassano, Italy
| | - A D'Avolio
- Unit of Infectious Diseases, University of Turin, Department of Medical Sciences, Amedeo di Savoia Hospital, Turin, Italy
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Abstract
Contrast source inversion electric properties tomography (CSI-EPT) is a recently developed technique for the electric properties tomography that recovers the electric properties distribution starting from measurements performed by magnetic resonance imaging scanners. This method is an optimal control approach based on the contrast source inversion technique, which distinguishes itself from other electric properties tomography techniques for its capability to recover also the local specific absorption rate distribution, essential for online dosimetry. Up to now, CSI-EPT has only been described in terms of integral equations, limiting its applicability to homogeneous unbounded background. In order to extend the method to the presence of a shield in the domain-as in the recurring case of shielded radio frequency coils-a more general formulation of CSI-EPT, based on a functional viewpoint, is introduced here. Two different implementations of CSI-EPT are proposed for a 2-D transverse magnetic model problem, one dealing with an unbounded domain and one considering the presence of a perfectly conductive shield. The two implementations are applied on the same virtual measurements obtained by numerically simulating a shielded radio frequency coil. The results are compared in terms of both electric properties recovery and local specific absorption rate estimate, in order to investigate the requirement of an accurate modeling of the underlying physical problem.
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26
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Giverso C, Arduino A, Preziosi L. How Nucleus Mechanics and ECM Microstructure Influence the Invasion of Single Cells and Multicellular Aggregates. Bull Math Biol 2017; 80:1017-1045. [PMID: 28409417 DOI: 10.1007/s11538-017-0262-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 02/17/2017] [Indexed: 01/14/2023]
Abstract
In order to move in a three-dimensional extracellular matrix, the nucleus of a cell must squeeze through the narrow spacing among the fibers and, by adhering to them, the cell needs to exert sufficiently strong traction forces. If the nucleus is too stiff, the spacing too narrow, or traction forces too weak, the cell is not able to penetrate the network. In this article, we formulate a mathematical model based on an energetic approach, for cells entering cylindrical channels composed of extracellular matrix fibers. Treating the nucleus as an elastic body covered by an elastic membrane, the energetic balance leads to the definition of a necessary criterion for cells to pass through the regular network of fibers, depending on the traction forces exerted by the cells (or possibly passive stresses), the stretchability of the nuclear membrane, the stiffness of the nucleus, and the ratio of the pore size within the extracellular matrix with respect to the nucleus diameter. The results obtained highlight the importance of the interplay between mechanical properties of the cell and microscopic geometric characteristics of the extracellular matrix and give an estimate for a critical value of the pore size that represents the physical limit of migration and can be used in tumor growth models to predict their invasive potential in thick regions of ECM.
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Affiliation(s)
- Chiara Giverso
- Istituto Nazionale di Alta Matematica "F. Severi", Città Universitaria, P.le Aldo Moro 5, 00185, Rome, Italy.
- Department of Mathematical Sciences, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy.
| | - Alessandro Arduino
- Department of Energy, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
- Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135, Turin, Italy
| | - Luigi Preziosi
- Department of Mathematical Sciences, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin, Italy
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27
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Zilberti L, Arduino A, Bottauscio O, Chiampi M. The underestimated role of gradient coils in MRI safety. Magn Reson Med 2016; 77:13-15. [PMID: 27851880 DOI: 10.1002/mrm.26544] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 10/13/2016] [Accepted: 10/16/2016] [Indexed: 02/07/2023]
Affiliation(s)
- Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica, Torino, Italy
| | - Alessandro Arduino
- Istituto Nazionale di Ricerca Metrologica, Torino, Italy.,Politecnico di Torino, Dipartimento Energia, Torino, Italy
| | | | - Mario Chiampi
- Politecnico di Torino, Dipartimento Energia, Torino, Italy
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28
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Zilberti L, Arduino A, Bottauscio O, Chiampi M. Parametric analysis of transient skin heating induced by terahertz radiation. Bioelectromagnetics 2014; 35:314-23. [PMID: 24510310 DOI: 10.1002/bem.21842] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 01/09/2014] [Indexed: 12/17/2022]
Abstract
This paper investigates the effect of relevant physical parameters on transient temperature elevation induced in human tissues by electromagnetic waves in the terahertz (THz) band. The problem is defined by assuming a plane wave, which, during a limited time interval, normally impinges on the surface of a 3-layer model of the human body, causing a thermal transient. The electromagnetic equations are solved analytically, while the thermal ones are handled according to the finite element method. A parametric analysis is performed with the aim of identifying the contribution of each parameter, showing that the properties of the first skin layer (except blood flow) play a major role in the computation of the maximum temperature rise for the considered exposure situation. Final results, obtained by combining all relevant parameters together, show that the deviation from the reference solution of the maximum temperature elevation in skin is included in the coverage intervals from -30% to +10% at 0.1 THz and from -33% to +18% at 1 THz (with 95% confidence level). These data allow bounding the possible temperature increase against the spread of tissue properties that could be reasonably used for dosimetric simulations.
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Affiliation(s)
- Luca Zilberti
- Istituto Nazionale di Ricerca Metrologica (National Institute of Metrological Research), Torino, Italy
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29
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Preti G, Arduino A, Pera P. Consistency of performance of a new craniostat for oblique lateral transcranial radiographs of the temporomandibular joint. J Prosthet Dent 1984; 52:270-4. [PMID: 6590843 DOI: 10.1016/0022-3913(84)90111-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A new craniostat for use with OLTP radiography of the TMJ is described. In a clinical study of 20 patients the craniostat demonstrated a satisfactory consistency of radiographic reproduction.
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30
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Arduino A, Chiarabaglio M. [Instrumental relaxation of the masticatory muscles with EMG biofeedback. A clinico-experimental study]. Minerva Stomatol 1984; 33:49-57. [PMID: 6584725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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31
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Modica R, Preti G, Arduino A, Bruscagin C, Pera P, Pezzoli M, Scotti R. [Complete dentures: theoretical premises and practical applications]. Minerva Stomatol 1983; 32:325-56. [PMID: 6350838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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32
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Preti G, Arduino A, Scotti R. [A new method for position casts]. Minerva Stomatol 1983; 32:135-7. [PMID: 6341805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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