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https://www.readbyqxmd.com/read/28227992/modeling-and-design-of-antennas-for-implantable-telemetry-applications
#1
Arun Venkatasubramanian, Brandon Gifford, Arun Venkatasubramanian, Brandon Gifford, Brandon Gifford, Arun Venkatasubramanian
Incorporating an RF communications link in an implanted medical device can increase its range of applicability and improve quality of life for the patient. Developments in support electronics decrease design risk, but the implanted antenna remains a critical component of a communications link that operates at very low received power. Transmitted power is limited both by regulatory restrictions and, for most implanted devices, by power source capacity. Dielectric losses and wave trapping in the body result in transmission losses much greater than seen in free space communications...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227939/effects-of-coplanar-shielding-for-high-field-mri
#2
Joseph V Rispoli, Matthew D Wilcox, Samantha By, Steven M Wright, Mary P McDougall, Joseph V Rispoli, Matthew D Wilcox, Samantha By, Steven M Wright, Mary P McDougall, Matthew D Wilcox, Steven M Wright, Samantha By, Mary P McDougall, Joseph V Rispoli
This work investigates the efficacy of "coplanar shielding," in which copper shields are oriented concentric and coplanar to the RF coils rather than implemented as a full ground plane behind them. Following FDTD simulations to determine optimal shielding parameters, two coil geometries were constructed: a circular loop surface coil and a half-volume five-element receive array. Each was evaluated using bench measurements with and without coplanar shielding. Imaging, including accelerated SENSE imaging, was performed with the shielded and unshielded receive arrays on a whole-body 7T scanner...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227938/integrated-rf-shim-coil-allowing-two-degrees-of-freedom-shim-current
#3
Jiazheng Zhou, Ying-Hua Chu, Yi-Cheng Hsu, Pu-Yeh Wu, Jason P Stockmann, Fa-Hsuan Lin, Jiazheng Zhou, Ying-Hua Chu, Yi-Cheng Hsu, Pu-Yeh Wu, Jason P Stockmann, Fa-Hsuan Lin, Pu-Yeh Wu, Jason P Stockmann, Fa-Hsuan Lin, Jiazheng Zhou, Ying-Hua Chu, Yi-Cheng Hsu
High-quality magnetic resonance imaging and spectroscopic measurements require a highly homogeneous magnetic field. Different from global shimming, localized off-resonance can be corrected by using multi-coil shimming. Previously, integrated RF and shimming coils have been used to implement multi-coil shimming. Such coils share the same conductor for RF signal reception and shim field generation. Here we propose a new design of the integrated RF-shim coil at 3-tesla, where two independent shim current paths are allowed in each coil...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227937/effects-of-tuning-conditions-on-near-field-of-mri-transmit-birdcage-coil-at-64-mhz
#4
Mikhail Kozlov, Elena Lucano, Leonardo M Angelone, Mikhail Kozlov, Elena Lucano, Leonardo M Angelone, Elena Lucano, Leonardo M Angelone, Mikhail Kozlov
This study investigates how the tuning conditions of a 64 MHz / 1.5 T radio frequency (RF) birdcage coil modeled with an RF circuit and 3D electromagnetic co-simulation affect the electric and magnetic near-field distribution. Four models were implemented with different tuning conditions and difference between numerical results and measurements was evaluated. The results show that the simulated near-field depends significantly on coil tuning conditions, especially in volumes close to the ASTM phantom walls...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227936/radio-frequency-induced-heating-of-an-insulated-wire-during-magnetic-resonance-imaging
#5
Mikhail Kozlov, Gregor Schaefers, Mikhail Kozlov, Gregor Schaefers, Gregor Schaefers, Mikhail Kozlov
Radio frequency (RF) induced power deposition near straight insulated leads excited by different incident electrical field profiles was investigated. 3-D electromagnetic (EM) simulations were used to obtain implant models as well as RF-induced power depositions calculated as the integral of power loss density. For the investigated setups up to 400% discrepancy between the implant model predictions and EM simulation values was observed.
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227630/an-rf-powering-system-with-adaptive-impedance-matching-for-individual-health-monitoring-applications
#6
Zemin Liu, Yu-Pin Hsu, Mona M Hella, Zemin Liu, Yu-Pin Hsu, Mona M Hella, Yu-Pin Hsu, Mona M Hella, Zemin Liu
This paper presents a high-efficiency RF powering system, suitable for individual health monitoring applications. The system is composed of an antenna, an impedance matching network, and a two-stage full-wave RF-DC rectifier. A novel tuning mechanism is proposed to automatically adjust the impedance of the matching network. This mechanism can effectively improve the power efficiency of the system by 47% compared to the case without tuning. For the adaptive impedance, only a 5-bits binary weighted capacitor bank is required in the matching network...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227593/an-rf-based-wearable-sensor-system-for-indoor-tracking-to-facilitate-efficient-healthcare-management
#7
Yuzhe Ouyang, Kai Shan, Francis Minhthang Bui, Yuzhe Ouyang, Kai Shan, Francis Minhthang Bui, Yuzhe Ouyang, Kai Shan, Francis Minhthang Bui
To understand the utilization of clinical resources and improve the efficiency of healthcare, it is often necessary to accurately locate patients and doctors in a healthcare facility. However, existing tracking methods, such as GPS, Wi-Fi and RFID, have technological drawbacks or impose significant costs, thus limiting their applications in many clinical environments, especially those with indoor enclosures. This paper proposes a low-cost and flexible tracking system that is well suited for operating in an indoor environment...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227589/uhf-wearable-battery-free-sensor-module-for-activity-and-falling-detection
#8
Nam Trung Dang, Thang Viet Tran, Wan-Young Chung, Nam Trung Dang, Thang Viet Tran, Wan-Young Chung, Thang Viet Tran, Wan-Young Chung, Nam Trung Dang
Falling is one of the most serious medical and social problems in aging population. Therefore taking care of the elderly by detecting activity and falling for preventing and mitigating the injuries caused by falls needs to be concerned. This study proposes a wearable, wireless, battery free ultra-high frequency (UHF) smart sensor tag module for falling and activity detection. The proposed tag is powered by UHF RF wave from reader and read by a standard UHF Electronic Product Code (EPC) Class-1 Generation-2 reader...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227588/variation-of-radio-frequency-induced-power-deposition-due-to-second-surrounding-tissue
#9
Mikhail Kozlov, Gregor Schaefers, Mikhail Kozlov, Gregor Schaefers, Gregor Schaefers, Mikhail Kozlov
We investigated RF-induced power deposition (p) generated by insulated leads with different lengths located in proximity to two tissues. The first tissue surrounding the leads was shaped as a cylinder with a diameter of 11 mm and located in a very large box filled with the second tissue. Lead electromagnetic models and p substantially depended on electrical properties of both tissues. If the cylinder and the box were filled with the same tissue, discrepancy to results of the two-tissue setup was up to 280%.
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227421/spectral-based-pneumonia-detection-tool-using-ultrasound-data-from-pediatric-populations
#10
O Zenteno, B Castaneda, R Lavarello, O Zenteno, B Castaneda, R Lavarello, B Castaneda, O Zenteno, R Lavarello
Pediatric Pneumonia is one of the principal causes of death by year on children under the age of five worldwide. The diagnosis is commonly made by clinical criteria with support from imaging tools like radiography. Lung ultrasound has been considered a low-cost and portable alternative for pneumonia imaging; however, interpretation is subjective and requires adequate training. In the present work, a pneumonia detection algorithm based on the measurement of the fundamental bandwidth downshift over depth of ultrasound radiofrequency (RF) signals is presented...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227298/extracting-dielectric-spectroscopic-properties-from-microwave-induced-thermoacoustic-signals
#11
Shiyu Liu, Hao Nan, Nemat Dolatsha, Amin Arbabian, Shiyu Liu, Hao Nan, Nemat Dolatsha, Amin Arbabian, Hao Nan, Nemat Dolatsha, Amin Arbabian, Shiyu Liu
Available data on the dielectric properties of biological tissue across a frequency range adds an extra degree of freedom of contrast besides the baseline structural information obtained by conventional imaging techniques. In this paper, we propose a new methodology to non-invasively extract the normalized effective conductivity of samples over a large frequency range using microwave-induced thermoacoustic (TA) signals. Additionally, a calibration approach has been adopted to remove the frequency dependency of the experimental setup errors as well as the RF power variation...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227244/towards-development-of-a-mobile-rf-doppler-sensor-for-continuous-heart-rate-variability-and-blood-pressure-monitoring
#12
Insoo Kim, Yusuf A Bhagat, Insoo Kim, Yusuf A Bhagat, Insoo Kim, Yusuf A Bhagat
The standard in noninvasive blood pressure (BP) measurement is an inflatable cuff device based on the oscillometric method, which poses several practical challenges for continuous BP monitoring. Here, we present a novel ultra-wide band RF Doppler radar sensor for next-generation mobile interface for the purpose of characterizing fluid flow speeds, and for ultimately measuring cuffless blood flow in the human wrist. The system takes advantage of the 7.1~10.5 GHz ultra-wide band signals which can reduce transceiver complexity and power consumption overhead...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227205/low-frequency-ultrasound-radiosensitization-and-therapy-response-monitoring-of-tumors-an-in-vivo-study
#13
Ali Sadeghi-Naini, Martin Stanisz, Hadi Tadayyon, Jaswinder Taank, Gregory J Czarnota, Ali Sadeghi-Naini, Martin Stanisz, Hadi Tadayyon, Jaswinder Taank, Gregory J Czarnota, Jaswinder Taank, Hadi Tadayyon, Martin Stanisz, Ali Sadeghi-Naini, Gregory J Czarnota
A new framework has been introduced in this paper for tumor radiosensitization and therapy response monitoring using low-frequency ultrasound. Human fibrosarcoma xenografts grown in severe combined immunodeficiency (SCID) mice (n = 108) were treated using ultrasound-stimulated microbubbles at various concentration and exposed to different doses of radiation. Low-frequency ultrasound radiofrequency (RF) data were acquired from tumors prior to and at different times after treatment. Quantitative ultrasound (QUS) techniques were applied to generate spectral parametric maps of tumors...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227161/in-to-out-body-path-loss-for-wireless-radio-frequency-capsule-endoscopy-in-a-human-body
#14
G Vermeeren, E Tanghe, A Thielens, L Martens, W Joseph, G Vermeeren, E Tanghe, A Thielens, L Martens, W Joseph, E Tanghe, A Thielens, L Martens, G Vermeeren, W Joseph
Physical-layer characterization is important for design of in-to-out body communication for wireless body area networks (WBANs). This paper numerically investigates the path loss of an in-to-out body radio frequency (RF) wireless link between an endoscopy capsule and a receiver outside the body using a 3D electromagnetic solver. A spiral antenna in the endoscopy capsule is tuned to operate in the Medical Implant Communication Service (MICS) band at 402 MHz, accounting for the properties of the human body. The influence of misalignment, rotation of the capsule, and human body model are investigated...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227127/effects-of-the-geometry-and-size-of-the-cerebrospinal-fluid-on-mri-transmit-and-safety-efficiencies-at-300-mhz
#15
Mikhail Kozlov, Pierre-Louis Bazin, Nikolaus Weiskopf, Harald Moller, Mikhail Kozlov, Pierre-Louis Bazin, Nikolaus Weiskopf, Harald Moller, Pierre-Louis Bazin, Nikolaus Weiskopf, Harald Moller, Mikhail Kozlov
We investigated effects of the geometry and size of the cerebrospinal fluid (CSF) on transmit and safety efficiencies in magnetic resonance imaging at 300 MHz. For the human model investigated here and a head position at the top of the RF coil, an increase of CSF space resulted in essential degradation of the safety excitation efficiency without an easily recognizable influence on the magnetic field distribution. For a head location in the coil center, CSF space variation did not significantly change the safety excitation and transmit efficiencies...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227125/random-forests-for-dura-mater-microvasculature-segmentation-using-epifluorescence-images
#16
Yasmin M Kassim, V B Surya Prasath, Rengarajan Pelapur, Olga V Glinskii, Richard J Maude, Vladislav V Glinsky, Virginia H Huxley, Kannappan Palaniappan, Yasmin M Kassim, V B Surya Prasath, Rengarajan Pelapur, Olga V Glinskii, Richard J Maude, Vladislav V Glinsky, Virginia H Huxley, Kannappan Palaniappan, Virginia H Huxley, Yasmin M Kassim, Rengarajan Pelapur, Kannappan Palaniappan, Vladislav V Glinsky, Olga V Glinskii, Richard J Maude, V B Surya Prasath
Automatic segmentation of microvascular structures is a critical step in quantitatively characterizing vessel remodeling and other physiological changes in the dura mater or other tissues. We developed a supervised random forest (RF) classifier for segmenting thin vessel structures using multiscale features based on Hessian, oriented second derivatives, Laplacian of Gaussian and line features. The latter multiscale line detector feature helps in detecting and connecting faint vessel structures that would otherwise be missed...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227119/clinical-viability-of-carotid-plaque-strain-estimation-using-b-mode-ultrasound-image-sequences
#17
Amir A Khan, Joseph C Hecker, Brajesh K Lal, Siddhartha Sikdar, Amir A Khan, Joseph C Hecker, Brajesh K Lal, Siddhartha Sikdar, Siddhartha Sikdar, Brajesh K Lal, Amir A Khan, Joseph C Hecker
It is estimated that approximately 30% of ischemic strokes are caused by rupture of plaque in the carotid artery. Development of techniques focusing on identifying plaques that are vulnerable to rupture is thus indispensable for stroke prevention. Recent studies have demonstrated that motion analysis of plaques from B-mode and RF ultrasound (US) image sequences can be used to estimate plaque strain. However, viability of these methods in a clinical setting, with variable acquisition protocols, has not been demonstrated yet...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227050/distance-metric-learning-using-random-forest-for-cytometry-data
#18
M Baran Pouyan, J Birjandtalab, M Nourani, M Baran Pouyan, J Birjandtalab, M Nourani, M Baran Pouyan, J Birjandtalab, M Nourani
Visualization and clustering of single-cell mass cytometry (CyTOF) data are analytic techniques to identify different cell types. Most of such techniques, such as Euclidean norm, lose their effectiveness when the data dimension increases due to the curse of dimensionality. In this paper, we propose a new cell distance (called CytoRFD) that works based on Random Forest (RF) concept. The experimental results show that the proposed distance can achieve a much higher quality and effectiveness in large data analysis than traditional metrics specially for CyTOF data...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227014/random-forests-to-predict-tumor-recurrence-following-cervical-cancer-therapy-using-pre-and-per-treatment-18-f-fdg-pet-parameters
#19
Geoffrey Roman-Jimenez, Oscar Acosta, Julie Leseur, Anne Devillers, Henri Der Sarkissian, Lina Guzman, Eloi'se Grossiord, Juan-David Ospina, Renaud De Crevoisier, Geoffrey Roman-Jimenez, Oscar Acosta, Julie Leseur, Anne Devillers, Henri Der Sarkissian, Lina Guzman, Eloi'se Grossiord, Juan-David Ospina, Renaud De Crevoisier, Oscar Acosta, Julie Leseur, Juan-David Ospina, Geoffrey Roman-Jimenez, Henri Der Sarkissian, Renaud De Crevoisier, Anne Devillers, Eloise Grossiord, Lina Guzman
The ability to predict tumor recurrence after chemoradiotherapy of locally advanced cervical cancer is a crucial clinical issue to intensify the treatment of the most high-risk patients. The objective of this study was to investigate tumor metabolism characteristics extracted from pre- and per-treatment (18)F-FDG PET images to predict 3-year overall recurrence (OR). A total of 53 locally advanced cervical cancer patients underwent pre- and per-treatment (18)F-FDG PET (respectively PET1 and PET2). Tumor metabolism was characterized through several delineations using different thresholds, based on a percentage of the maximum uptake, and applied by region-growing...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226994/high-dielectric-material-in-mri-numerical-assessment-of-the-reduction-of-the-induced-local-power-on-implanted-cardiac-leads
#20
Eugenio Mattei, Elena Lucano, Federica Censi, Leonardo M Angelone, Giovanni Calcagnini, Eugenio Mattei, Elena Lucano, Federica Censi, Leonardo M Angelone, Giovanni Calcagnini, Eugenio Mattei, Giovanni Calcagnini, Elena Lucano, Leonardo M Angelone, Federica Censi
High dielectric materials (HDM) have been proposed in magnetic resonance imaging (MRI) to increase the signal-to-noise ratio (SNR) of the images acquired while reducing the radiofrequency (RF) absorption in tissue. The aim of this study is to assess the potential merit of using HDM to reduce power induced at the tip of an endocardial lead in patients undergoing MRI. Numerical simulations were performed using a commercial finite-differences time-domain (FDTD) software to model the RF field generated by a birdcage body coil at 64 MHz on a human body model...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
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