- Email: [email protected]
Numerical simulation and experimental validation of magnetic nanoparticle hyperthermia
Abstracts / Physica Medica 32 (2016) 251–273
NUMERICAL SIMULATION AND EXPERIMENTAL VALIDATION OF MAGNETIC NANOPARTICLE HYPERTHERMIA Costas Papadopoulos a,*, George Loudos b,c, Eleni Efthimiadou d, George Kordas d, George Kagadis a a Department of Medical Physics, School of Medicine, University of Patras, Greece b Institute of Nuclear & Radiological Sciences, Technology, Energy & Safety, NCSR ”Demokritos”, Greece c Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece d SOL-GEL Laboratory, Institute of Nanoscience and Nanotechnology, NCSR ‘‘Demokritos”, Greece ⇑ Corresponding author.
Introduction. Magnetic Nanoparticle Hyperthermia constitutes one of the latest promising treatments for cancerous tumors. The basic principle of hyperthermia lies on the necrosis of cancer cells for temperatures above the threshold of 42 °C, while healthy tissue undergoes negligible damage. Purpose. The objectives of the conducted research included the setup and validation of a numerical simulation based on Rosensweig’s analytical relationships, in order to calculate the volumetric power dissipation due to magnetic nanoparticles in the matrix fluid or tissue (SAR – Specific Absorption Rate or SLP – Specific Loss Power). Materials and methods. To simulate the experimental setup, as well as the heating process a numerical model was developed using Comsol Multiphysics software. Comsol solvers use FEM (Finite Element Methods) for approximating partial differential equations. To validate the numerical simulation, water based ferrofluids containing superparamagnetic iron oxide nanoparticles (Fe3O4) in different concentrations were prepared. The samples were exposed to an alternating magnetic field produced by a solenoid connected to an ‘‘Easy Heat” system. Optical fiber was immersed in the subject ferrofluid in order to measure its temperature. The acquired data were processed to obtain hyperthermia heating curves. The geometry, parameters and variables of the experiment were implemented to Comsol Multiphysics. Results. The simulated magnetic field, was validated using analytical expressions. Small divergence was observed, since Comsol software uses partial differential equations to compute the field amplitude and gradient accurately. The results produced by the numerical simulation concerning the heating process, were in agreement with those obtained during the experimental procedure. Conclusion. In this study, the numerical simulation of ferrofluid heating was validated. The successful analytical description of this in vitro application, encourages the development of advanced models, designed for simulating in vivo applications. http://dx.doi.org/10.1016/j.ejmp.2016.07.557
FACTORS AFFECTING EXPOSURE PARAMETERS DURING DIAGNOSTIC CORONARY CATHETERIZATION M. Habibi *, N. Kollaros, P. Karyofyllis, I. Mastorakou, V. Voudris 2nd Department of Invasive Cardiology, Onassis Cardiac Surgery Centre, Athens, Greece ⇑ Corresponding author. Introduction. Diagnostic cardiac catheterization represents an important source of radiation. Although transradial access (TRA) is being increasingly used in interventional cardiology, there are concerns about a possible increase in radiation exposure as compared to transfemoral access (TFA).
259
Purpose. The aim of this study is the comparison of radiation exposure parameters between coronary angiography procedures performed via left radial artery, right radial artery or femoral artery and the detection of factors that contribute to increased radiation dose. Materials and methods. We analyzed collected data on radiation exposure for a total of 1165 consecutive diagnostic coronary angiographies excluded those concerning patients with aortocoronary bypass grafts. Dose area product (DAP) and fluoroscopy time (FT) were used as a means of radiation exposure measurement. Results. The mean patients’ age was 66 ± 11 years and BMI 28.4 ± 4.6 kg/m2. Femoral access was used in 36.7% of the procedures, right radial access (RRA) in 50% and left radial access (LRA) in 13.3%. TRA was associated with increased FT (4.6 ± 3.3 vs 3.0 ± 2.5 min, p < 0.001) and DAP (31.9 ± 18.2 vs 28.6 ± 15 Gycm2, p = 0.001). There were no differences regarding FT and DAP between RRA and LRA. Hypertension, the presence of ascending aorta aneurysm and the presence of coronary artery disease were predictors of increased exposure parameters, whereas diabetes mellitus was predictor of increased DAP. Conclusion. TRA is associated with increased exposure parameters as compared to TFA, but there are no differences between RRA and LRA. Hypertension, ascending aorta aneurysm and coronary artery disease are adversely affecting exposure parameters. http://dx.doi.org/10.1016/j.ejmp.2016.07.558
VALIDATION MEASUREMENTS FOR THE RETROSPECTIVE CALCULATION OF EYE LENS DOSES OF INTERVENTIONAL CARDIOLOGISTS Eleftheria Carinou a,*, Panagiotis Askounis a, Danielle Berus b, Olivera Ciraj-Bjelac c, Isabelle Clairand d, Peter Covens b, Jérémie Dabin e, Joanna Domienik f, Jad Farah d, Joanna Jurewicz f, Renato Padovani g, Lara Struelens e a
Greek Atomic Energy Commission (GAEC), Athens, Greece University of Brussels (VUB), Brussels, Belgium c Vinca Institute for Nuclear Sciences (VINCA), Belgrade, Serbia d Institute for Radiological Protection and Nuclear Safety (IRSN), Paris, France e Belgian Nuclear Research Centre (SCKCEN), Mol, Belgium f Nofer Institute of Occupational Medicine (NIOM), Lodz, Poland g International Centre for Theoretical Physics (ICTP), Trieste, Italy ⇑ Corresponding author. b
Introduction. The eye lens radiation-induced risk has been assessed for various population groups. In the framework of the European epidemiological study, EURALOC, an attempt is made to determine a possible dose-response relationship by targeting interventional cardiologists, a group of high exposure values. Purpose. In the study, eye lens doses are assessed using two approaches: combining self-reported data on working practices and eye lens doses from literature (approach 1); and converting the whole-body dose values to eye lens doses (approach 2). Eye lens dose measurements are performed to validate both approaches and to determine their associated uncertainties. Materials and methods. Eye lens dose measurements are performed on cardiologists in routine practice using commercially available dedicated eye lens dosemeters. Furthermore, whole-body dose values are obtained from whole-body dosemeters worn above the lead apron at the chest left position. Exposure information including tube orientation, operator position and orientation are collected. Results. The first values of eye lens doses measured in routine clinical conditions are in good agreement with eye lens dose estimates obtained with the two approaches No systematic errors have been found which is encouraging in order to continue using either of
NUMERICAL SIMULATION AND EXPERIMENTAL VALIDATION OF MAGNETIC NANOPARTICLE HYPERTHERMIA Costas Papadopoulos a,*, George Loudos b,c, Eleni Efthimiadou d, George Kordas d, George Kagadis a a Department of Medical Physics, School of Medicine, University of Patras, Greece b Institute of Nuclear & Radiological Sciences, Technology, Energy & Safety, NCSR ”Demokritos”, Greece c Department of Biomedical Engineering, Technological Educational Institute of Athens, Greece d SOL-GEL Laboratory, Institute of Nanoscience and Nanotechnology, NCSR ‘‘Demokritos”, Greece ⇑ Corresponding author.
Introduction. Magnetic Nanoparticle Hyperthermia constitutes one of the latest promising treatments for cancerous tumors. The basic principle of hyperthermia lies on the necrosis of cancer cells for temperatures above the threshold of 42 °C, while healthy tissue undergoes negligible damage. Purpose. The objectives of the conducted research included the setup and validation of a numerical simulation based on Rosensweig’s analytical relationships, in order to calculate the volumetric power dissipation due to magnetic nanoparticles in the matrix fluid or tissue (SAR – Specific Absorption Rate or SLP – Specific Loss Power). Materials and methods. To simulate the experimental setup, as well as the heating process a numerical model was developed using Comsol Multiphysics software. Comsol solvers use FEM (Finite Element Methods) for approximating partial differential equations. To validate the numerical simulation, water based ferrofluids containing superparamagnetic iron oxide nanoparticles (Fe3O4) in different concentrations were prepared. The samples were exposed to an alternating magnetic field produced by a solenoid connected to an ‘‘Easy Heat” system. Optical fiber was immersed in the subject ferrofluid in order to measure its temperature. The acquired data were processed to obtain hyperthermia heating curves. The geometry, parameters and variables of the experiment were implemented to Comsol Multiphysics. Results. The simulated magnetic field, was validated using analytical expressions. Small divergence was observed, since Comsol software uses partial differential equations to compute the field amplitude and gradient accurately. The results produced by the numerical simulation concerning the heating process, were in agreement with those obtained during the experimental procedure. Conclusion. In this study, the numerical simulation of ferrofluid heating was validated. The successful analytical description of this in vitro application, encourages the development of advanced models, designed for simulating in vivo applications. http://dx.doi.org/10.1016/j.ejmp.2016.07.557
FACTORS AFFECTING EXPOSURE PARAMETERS DURING DIAGNOSTIC CORONARY CATHETERIZATION M. Habibi *, N. Kollaros, P. Karyofyllis, I. Mastorakou, V. Voudris 2nd Department of Invasive Cardiology, Onassis Cardiac Surgery Centre, Athens, Greece ⇑ Corresponding author. Introduction. Diagnostic cardiac catheterization represents an important source of radiation. Although transradial access (TRA) is being increasingly used in interventional cardiology, there are concerns about a possible increase in radiation exposure as compared to transfemoral access (TFA).
259
Purpose. The aim of this study is the comparison of radiation exposure parameters between coronary angiography procedures performed via left radial artery, right radial artery or femoral artery and the detection of factors that contribute to increased radiation dose. Materials and methods. We analyzed collected data on radiation exposure for a total of 1165 consecutive diagnostic coronary angiographies excluded those concerning patients with aortocoronary bypass grafts. Dose area product (DAP) and fluoroscopy time (FT) were used as a means of radiation exposure measurement. Results. The mean patients’ age was 66 ± 11 years and BMI 28.4 ± 4.6 kg/m2. Femoral access was used in 36.7% of the procedures, right radial access (RRA) in 50% and left radial access (LRA) in 13.3%. TRA was associated with increased FT (4.6 ± 3.3 vs 3.0 ± 2.5 min, p < 0.001) and DAP (31.9 ± 18.2 vs 28.6 ± 15 Gycm2, p = 0.001). There were no differences regarding FT and DAP between RRA and LRA. Hypertension, the presence of ascending aorta aneurysm and the presence of coronary artery disease were predictors of increased exposure parameters, whereas diabetes mellitus was predictor of increased DAP. Conclusion. TRA is associated with increased exposure parameters as compared to TFA, but there are no differences between RRA and LRA. Hypertension, ascending aorta aneurysm and coronary artery disease are adversely affecting exposure parameters. http://dx.doi.org/10.1016/j.ejmp.2016.07.558
VALIDATION MEASUREMENTS FOR THE RETROSPECTIVE CALCULATION OF EYE LENS DOSES OF INTERVENTIONAL CARDIOLOGISTS Eleftheria Carinou a,*, Panagiotis Askounis a, Danielle Berus b, Olivera Ciraj-Bjelac c, Isabelle Clairand d, Peter Covens b, Jérémie Dabin e, Joanna Domienik f, Jad Farah d, Joanna Jurewicz f, Renato Padovani g, Lara Struelens e a
Greek Atomic Energy Commission (GAEC), Athens, Greece University of Brussels (VUB), Brussels, Belgium c Vinca Institute for Nuclear Sciences (VINCA), Belgrade, Serbia d Institute for Radiological Protection and Nuclear Safety (IRSN), Paris, France e Belgian Nuclear Research Centre (SCKCEN), Mol, Belgium f Nofer Institute of Occupational Medicine (NIOM), Lodz, Poland g International Centre for Theoretical Physics (ICTP), Trieste, Italy ⇑ Corresponding author. b
Introduction. The eye lens radiation-induced risk has been assessed for various population groups. In the framework of the European epidemiological study, EURALOC, an attempt is made to determine a possible dose-response relationship by targeting interventional cardiologists, a group of high exposure values. Purpose. In the study, eye lens doses are assessed using two approaches: combining self-reported data on working practices and eye lens doses from literature (approach 1); and converting the whole-body dose values to eye lens doses (approach 2). Eye lens dose measurements are performed to validate both approaches and to determine their associated uncertainties. Materials and methods. Eye lens dose measurements are performed on cardiologists in routine practice using commercially available dedicated eye lens dosemeters. Furthermore, whole-body dose values are obtained from whole-body dosemeters worn above the lead apron at the chest left position. Exposure information including tube orientation, operator position and orientation are collected. Results. The first values of eye lens doses measured in routine clinical conditions are in good agreement with eye lens dose estimates obtained with the two approaches No systematic errors have been found which is encouraging in order to continue using either of