A GMR sensor based guiding tool for location of metal shrapnel during surgery
01 Dec 2013-pp 640-644
TL;DR: A Giant Magneto Resistance (GMR) sensor based online surgical tool that helps to remove metal shrapnel from victim's body is presented, intended to guide the surgeon to the exact location of the shrapnel during surgery.
Abstract: Shrapnel injury is a major cause of death in victims of bomb blast, land mines and gun fire. In this paper, a Giant Magneto Resistance (GMR) sensor based online surgical tool that helps to remove metal shrapnel from victim's body is presented. This tool is intended to guide the surgeon to the exact location of the shrapnel during surgery. Presently doctors rely on imaging systems to locate them before surgery. Effectiveness of surgery solely depends on the doctors' skill to trace them, as these images do not provide real-time information of the location of the shrapnel during surgery. Therefore, in some cases, the shrapnel, in spite of being visible in the images, may become untraceable during surgery. So in such cases, a sensing tool that can guide the doctor to the location of the shrapnel will be very effective. An inductive proximity sensor can serve this purpose, but its output can be affected by its lead inductance or other parasitic circuit parameters. Therefore in order to overcome such effects, a GMR based sensing tool is proposed here. The details and experimental results obtained from this tool are presented in this paper. The tool can detect both ferromagnetic and paramagnetic metal targets.
Citations
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TL;DR: In this article, a tunneling magnetoresistance (TMR) sensor is applied to take the place of the coil in a conventional EMT system, and the advantages of a TMR sensor on the frequency-independence and spatial resolution were investigated.
Abstract: A magnetic catalyst could be applied in a fluidized bed to improve the catalytic efficiency in the methanation and selective hydrogenation processes. Its distributions play an important role in accelerating the reactions. Electromagnetic tomography (EMT) provides an effective solution for online monitoring of the distribution of a magnetic catalyst. However, most of the EMT systems were developed to investigate the conductivity distribution. A novel EMT for the reconstruction of permeability distribution is presented in this paper. The coils, of which the sensitivity are related to frequency and coil size, were used as receivers in conventional EMT systems. In this paper, a tunneling magnetoresistance (TMR) sensor is applied to take the place of the coil. Compared with coils, the advantages of a TMR sensor on the frequency-independence and spatial resolution were investigated. A coil-TMR array was designed, in which the coil geometry was optimized and the TMR sensor was selected. The sensitivity matrix of the novel system was calculated by the perturbation method in a 3D simulation model. A FPGA-based system was designed. The reconstruction results of the magnetic catalyst validated the practicability of the permeability EMT based on TMR sensors.
22 citations
01 Dec 2018
TL;DR: An improved field-feedback approach for GMR (FFG) sensors has been presented and it has been shown that the FFG improves the above characteristics of the sensor and also increases its measuring field range.
Abstract: Magnetic-feedback approach for improving the characteristic of a GMR sensor has been attempted in some research works. These works demonstrated an improvement in the linearity, hysteresis of the GMR characteristic and also facilitate measurement of negative fields. In this work, an improved field-feedback approach for GMR (FFG) sensors has been presented. It has been shown that the FFG improves the above characteristics of the sensor and also increases its measuring field range. An integrator circuit has been included in the FFG design. The integrator improves the dynamic response of the conventional feedback approach, by increasing overall system-damping. Moreover, it also facilities use of high loop-gain in the circuit which helps to reduce measurement error. The FFG, additionally, implements a dual-operating point technique, suitable for static fields. The output in the conventional feedback approach is largely dependent on an electromagnetic coil, present in the circuit. Dual-operating points, for biasing the GMR sensor, can be used to eliminate the effect of this parameter, completely. Extensive simulation results validate both these inclusions. It shows a reduction of error from 18 % to a negligible value, with dual-operating point technique, for static input fields. Subsequent experimental results, with a suitable prototype, further affirm the working and utility of the FFG.
3 citations
Cites background from "A GMR sensor based guiding tool for..."
...Applications [1-2] involving low magnetic-field (in Gauss-range) measurement, require the sensor to have high sensitivity and linearity, wide input range, low hysteresis, good accuracy and low-cost....
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11 Jun 2014
TL;DR: Details of new schemes that were evaluated to improve the detection depths of the GMR sensor based shrapnel detectors are presented and results on prototype detectors built and tested establish the feasibility of the proffered schemes.
Abstract: Injury due to metal shrapnel is a major cause of death in victims of bomb blast, land mines and gun fire. To recover these shrapnel surgically, surgeons use imaging systems for locating them inside the victim's body. Since these shrapnel are normally mobile, by the time the surgery starts, their positions would have changed making it very difficult for the surgeon to recover them. In certain cases, the shrapnel that are visible in the images can become untraceable during surgery. Giant Magneto Resistance (GMR) type sensor based tool to aid a surgeon to locate shrapnel was found to have poor depth response characteristics compared to inductive proximity sensor based tool. This paper presents the details of new schemes that were evaluated to improve the detection depths of the GMR sensor based shrapnel detectors. Results on prototype detectors built and tested establish the feasibility of the proffered schemes.
References
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TL;DR: The dielectric properties of tissues have been extracted from the literature of the past five decades and presented in a graphical format to assess the current state of knowledge, expose the gaps there are and provide a basis for the evaluation and analysis of corresponding data from an on-going measurement programme.
Abstract: The dielectric properties of tissues have been extracted from the literature of the past five decades and presented in a graphical format. The purpose is to assess the current state of knowledge, expose the gaps there are and provide a basis for the evaluation and analysis of corresponding data from an on-going measurement programme.
2,932 citations
TL;DR: In this article, a new eddy-current testing technique for surface or near-surface defect detection in nonmagnetic metals using giant magnetoresistive (GMR) sensors is introduced.
Abstract: The purpose of this paper is to introduce a new eddy-current testing technique for surface or near-surface defect detection in nonmagnetic metals using giant magnetoresistive (GMR) sensors. It is shown that GMR-based eddy-current probes are able to accurately detect short surface-breaking cracks in conductive materials. The self-rectifying property of the GMR sensor used in this study leads to a simplified signal conditioning circuit, which can be fully integrated on a silicon chip with the GMR sensor. The ability to manufacture probes having small dimensions and high sensitivity (220 mV/mT) to low magnetic fields over a broad frequency range (from dc up to 1 MHz) enhances the spatial resolution of such an eddy-current testing probe. Experimental results obtained by scanning two different probes over a slotted aluminum specimen are presented. General performance characteristics are demonstrated by measurements of surface and subsurface defects of different sizes and geometries. Dependence of the sensor output on orientation, liftoff distance, and excitation intensity is also investigated.
211 citations
"A GMR sensor based guiding tool for..." refers background in this paper
...Therefore, in order t detection depth, an attempt was done to perpendicular to the axis of the exciting field as p [14]....
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TL;DR: In accordance with the sensor analysis presented in this paper, design strategies to compensate for important sensor imperfections are recommended and challenges that are associated with ECS interfaces are identified, with focus on advanced industrial applications.
Abstract: This paper presents a comprehensive study of the design aspects of eddy-current displacement sensor (ECS) systems. In accordance with the sensor analysis presented in this paper, design strategies to compensate for important sensor imperfections are recommended. To this end, the challenges that are associated with ECS interfaces are identified, with focus on advanced industrial applications. This paper also provides a technical overview of the design advances of ECS interfaces proposed in the last decade and evaluates their pros and cons. Recently reported interface solutions for demanding industrial applications with respect to high resolution, stability, bandwidth, and low power consumption, at a sufficiently high excitation frequency, are addressed in more detail.
120 citations
"A GMR sensor based guiding tool for..." refers background in this paper
...An inductive proximity sensor (IPS) with suitable dimensions may serve this purpose, but it has a few limitations as explained in [5], [6]....
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TL;DR: An attempt is made to theoretically analyze the properties, such as size, conductivity, and permeability of the metal objects from the output, i.e., amplitude and phase of theMetal detector.
Abstract: Metal detectors are extensively used to find undesirable metal objects in processed food. In such a typical metal detector, the coils are coaxially arranged with the transmitting coil in the center and two receiving coils on the sides. The receiving coils are connected to a differential amplifier. When the magnetic field generated in the transmitting coil is disturbed by metal objects, the amplitude and phase of the output voltage of the differential amplifier change, and, thus, the existence of foreign metal pieces is detected. The relationship between the amplitude and phase of the output and the electromagnetic properties of the metal objects, however, has only been discussed experimentally so far. The authors have already developed the SRPM method to simultaneously estimate the electrical and magnetic properties of a spherical sample by vectorially measuring the difference in the impedance of two circular solenoid coils, one with and the other without a sample. An attempt is made to theoretically analyze the properties, such as size, conductivity, and permeability of the metal objects from the output, i.e., amplitude and phase of the metal detector. Based on this method, an equation to estimate the vector voltage induced in the receiving coil by the metal object is derived by using a spherical sample to simplify the analysis.
76 citations
"A GMR sensor based guiding tool for..." refers background in this paper
...The varying excitation field induces eddy currents in the metal target (shrapnel) [10], which will be sensed by the GMR IC....
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TL;DR: The steps involved in imaging of terror attack patients include conventional radiography, focused abdominal sonography in trauma, computed tomography, and angiography, with the judicious use of supplemental imaging.
Abstract: On September 11, 2001, the world changed. The vicious giant of terrorism that was dormant until that date had arisen. After the horrific mass-casualty terror attack on the United States, any and all forms of assault seem possible. Owing to the complexity of injuries encountered in terror attack victims, fast and accurate imaging plays an essential role in triage and identification of abnormalities associated with injuries. The radiologist becomes a crucial part of the first-line team of doctors treating these patients. Knowledge that the best available treatment is given to terror attack victims can enhance the strength and endurance of society against terror. On the basis of the authors' experience with terror events in Israel, the steps involved in imaging of terror attack patients include conventional radiography, focused abdominal sonography in trauma, computed tomography, and angiography, with the judicious use of supplemental imaging.
63 citations
Additional excerpts
...CT image of shrapnel inside a bomb blast victim and typical metal objects used [1]...
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