Acousto-Optic Catheter Tracking Sensor for Interventional MRI Procedures
TL;DR: An acousto-optical optical fiber sensor for tracking catheter position during interventional magnetic resonance imaging (MRI) to overcome RF induced heating of active markers and it has been successfully used to detect the position of a tacking coil in phantom in an imaging experiment.
Abstract: Objective: The objective of this paper is to introduce an acousto-optic optical fiber sensor for tracking catheter position during interventional magnetic resonance imaging (MRI) to overcome RF induced heating of active markers. Methods: The sensor uses a miniature coil coupled to a piezoelectric transducer, which is in turn mechanically connected to an optical fiber. The piezoelectric transducer converts the RF signal to acoustic waves in the optical fiber over a region including a fiber Bragg grating (FBG). The elastic waves in the fiber modulates the FBG geometry and hence the reflected light in the optical fiber. Since the coil is much smaller than the RF wavelength and the signal is transmitted on the dielectric optical fiber, the sensor effectively reduces RF induced heating risk. Proof of concept prototypes of the sensor are implemented using commercially available piezoelectric transducers and optical fibers with FBGs. The prototypes are characterized in a 1.5 T MRI system in comparison with an active tracking marker. Results: Acousto-optical sensor shows linear response with flip angle and it can be used to detect signals from multiple coils for potential orientation detection. It has been successfully used to detect the position of a tacking coil in phantom in an imaging experiment. Conclusion: Acousto-optical sensing is demonstrated for tracking catheters during interventional MRI. Real-time operation of the sensor requires sensitivity improvements like using a narrow band FBG. Significance: Acousto-optics provides a compact solution to sense RF signals in MRI with dielectric transmission lines.
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TL;DR: In this paper, the authors provide an overview of the recent advances in biomedical photonic sensors within the last five years, focusing on works using optical-fibre technology, employing diverse optical fibres, sensing techniques, and configurations applied in several medical fields.
Abstract: In this invited review, we provide an overview of the recent advances in biomedical photonic sensors within the last five years. This review is focused on works using optical-fibre technology, employing diverse optical fibres, sensing techniques, and configurations applied in several medical fields. We identified technical innovations and advancements with increased implementations of optical-fibre sensors, multiparameter sensors, and control systems in real applications. Examples of outstanding optical-fibre sensor performances for physical and biochemical parameters are covered, including diverse sensing strategies and fibre-optical probes for integration into medical instruments such as catheters, needles, or endoscopes.
16 citations
TL;DR: In this paper, the authors demonstrate the use of an active acousto-optic marker with enhanced visibility and reduced radiofrequency (RF)induced heating for interventional MRI.
Abstract: Purpose This work aims to demonstrate the use of an "active" acousto-optic marker with enhanced visibility and reduced radiofrequency (RF) -induced heating for interventional MRI. Methods The acousto-optic marker was fabricated using bulk piezoelectric crystal and π-phase shifted fiber Bragg grating (FBGs) and coupled to a distal receiver coil on an 8F catheter. The received MR signal is transmitted over an optical fiber to mitigate RF-induced heating. A photodetector converts the optical signal into electrical signal, which is used as the input signal to the MRI receiver plug. Acousto-optic markers were characterized in phantom studies. RF-induced heating risk was evaluated according to ASTM 2182 standard. In vivo real-time tracking capability was tested in an animal model under a 0.55T scanner. Results Signal-to-noise ratio (SNR) levels suitable for real-time tracking were obtained by using high sensitivity FBG and piezoelectric transducer with resonance matched to Larmor frequency. Single and multiple marker coils integrated to 8F catheters were readout for position and orientation tracking by a single acousto-optic sensor. RF-induced heating was significantly reduced compared to a coax cable connected reference marker. Real-time distal tip tracking of an active device was demonstrated in an animal model with a standard real-time cardiac MR sequence. Conclusion Acousto-optic markers provide sufficient SNR with a simple structure for real-time device tracking. RF-induced heating is significantly reduced compared to conventional active markers. Also, multiple RF receiver coils connected on an acousto-optic modulator can be used on a single catheter for determining catheter orientation and shape.
8 citations
15 Mar 2020
TL;DR: A hybrid FBG model incorporating numerical and FEA methods was developed and used for sensitivity and linearity analysis and the impact of phase linearity of the FBG based acousto-optic sensor was tested under MRI.
Abstract: Fiber Bragg grating (FBG) based sensors have recently been introduced to the field of magnetic resonance imaging (MRI). Real-time MRI applications demand highly amplitude and phase sensitive MRI compatible sensors. Thus, a model and detailed analysis of FBG based ultrasound detection are required for designing better performing sensors. A hybrid FBG model incorporating numerical and FEA methods was developed and used for sensitivity and linearity analysis. The transfer matrix method was used for the modeling of optical modulation whereas FEA was used for pressure field calculations within the grating. The model was verified through reflection spectrum and acoustic pressure sensitivity testing of two π-phase shifted FBGs in a side slope read-out configuration. The sensitivity curves with respect to the operation point on the side slope was characterized in terms of amplitude and phase, and nonlinearity of the phase response has been quantified. Lastly, the impact of phase linearity of the FBG based acousto-optic sensor was tested under MRI when the sensor was used as a position marker and an analog phase shifter based solution was demonstrated.
4 citations
TL;DR: In this paper, a wireless music control system based on gesture tracking sensors is proposed, where an infrared sensor module based on the Internet of Things is used to automatically detect whether someone is approaching, and the motion tracking sensor module detects gestures and counts them through a counter.
Abstract: With the continuous development of society and rapid economic growth, intelligent music control technology has received more and more attention. At the same time, real-time motion tracking technology has also been developed more and more in the fields of virtual reality and human-machine control. This article is dedicated to developing a wireless music control system based on gesture tracking sensors. First, in the data collection part, an infrared sensor module based on the Internet of Things is used to automatically detect whether someone is approaching. When detecting that someone is approaching, the motion tracking sensor module captures and detects gestures and counts them through a counter. Then, the IoT data transmission module sends the acquired gesture information from the sending end to the receiving end. Finally, the particle swarm algorithm performs algorithmic intelligent processing and judgment on the transmitted data to realize wireless control of background music. After software and hardware debugging, a wireless music control model based on motion tracking was finally successfully established. The system has undergone a complete test, and the test results show that the system has strong stability. Users can easily control music equipment and achieve high accuracy of music control information.
2 citations
TL;DR: In this paper, an extrinsic Fabry-Perot interferometer (EFPI)-based temperature sensor, constructed using a novel diaphragm manufacturing technique, was compared with a reference all-glass EFPI temperature sensor.
Abstract: The following presents a comparison of an extrinsic Fabry–Perot interferometer (EFPI)-based temperature sensor, constructed using a novel diaphragm manufacturing technique, with a reference all-glass EFPI temperature sensor. The novel diaphragm was manufactured using polyvinyl alcohol (PVA). The novel sensor fabrication involved fusing a single-mode fibre (SMF) to a length of fused quartz capillary, which has an inner diameter of 132 μm and a 220 μm outer diameter. The capillary was subsequently polished until the distal face of the capillary extended approximately 60 μm beyond that of the single mode fibre. Upon completion of polishing, the assembly is immersed in a solution of PVA. Controlled extraction resulted in creation of a thin diaphragm while simultaneously applying a protective coating to the fusion point of the SMF and capillary. The EFPI sensor is subsequently sealed in a second fluid-filled capillary, thereby creating a novel temperature sensor structure. Both temperature sensors were placed in a thermogravimetric analyser and heated from an indicated 30 °C to 100 °C to qualitatively compare sensitivities. Initial results indicated that the novel manufacturing technique both expedited production and produces a more sensitive sensor when compared to an all-glass construction.
2 citations
References
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TL;DR: In this paper, the spectral properties of fiber reflection and transmission gratings are described and examples are given to illustrate the wide variety of optical properties that are possible in fiber gratings.
Abstract: In this paper, we describe the spectral characteristics that can be achieved in fiber reflection (Bragg) and transmission gratings. Both principles for understanding and tools for designing fiber gratings are emphasized. Examples are given to illustrate the wide variety of optical properties that are possible in fiber gratings. The types of gratings considered include uniform, apodized, chirped, discrete phase-shifted, and superstructure gratings; short-period and long-period gratings; symmetric and tilted gratings; and cladding-mode and radiation-mode coupling gratings.
3,330 citations
"Acousto-Optic Catheter Tracking Sen..." refers background in this paper
...Wavelength of the reflected light, called Bragg wavelength (λBragg ), strongly depends on the periodicity of the mirrors and refractive index of the fiber core [34]....
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Book•
01 Jan 1987
1,194 citations
"Acousto-Optic Catheter Tracking Sen..." refers background in this paper
...Piezoelectric transducers have highest electro-mechanic coupling efficiency when operated at around their first resonance frequency [35]....
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TL;DR: The use of a fiber Fabry–Perot filter for detecting the wavelength shift of a Fiber Bragg grating sensor or network of sensor elements along a common fiber path is described.
Abstract: The use of a fiber Fabry–Perot filter for detecting the wavelength shift of a fiber Bragg grating sensor or network of sensor elements along a commonfiber path is described. Results obtained by using a system with four sensor elements are presented.
798 citations
"Acousto-Optic Catheter Tracking Sen..." refers background in this paper
...Moreover FBG modulators offer high bandwidth [30] and multiple FBGs can be easily fabricated on a single fiber [31] enabling multiple sensors on one optical fiber....
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Book•
01 Jan 1982
TL;DR: In this article, the authors explain the physics of how devices work and how they can be used in various applications as the field of optoelectronics has progressed from microphotonics to nanophotonics Illustrations and references from technical journals have been used to demonstrate the relevance of the theory to current important topics in industry.
Abstract: Integrated Optics explains the subject of optoelectronic devices and their use in integrated optics and fiber optic systems The approach taken is to emphasize the physics of how devices work and how they can be (and have been) used in various applications as the field of optoelectronics has progressed from microphotonics to nanophotonics Illustrations and references from technical journals have been used to demonstrate the relevance of the theory to currently important topics in industry By reading this book, scientists, engineers, students and engineering managers can obtain an overall view of the theory and the most recent technology in Integrated Optics
773 citations
"Acousto-Optic Catheter Tracking Sen..." refers background in this paper
...One approach for such modulation scheme is interferometer based acousto-optic modulators utilizing reflectors and a reference beam [24]....
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TL;DR: Techniques which can be used to follow the position of invasive devices in real‐time using magnetic resonance (MR) are described, made possible by incorporating one or more small RF coils into the device.
Abstract: Techniques which can be used to follow the position of invasive devices in real-time using magnetic resonance (MR) are described. Tracking of an invasive device is made possible by incorporating one or more small RF coils into the device. These coils detect MR signals from only those spins near the coil. Pulse sequences which employ nonselective RF pulses to excite all nuclear spins within the field-of-view are used. Readout magnetic field gradient pulses, typically applied along one of the primary axes of the imaging system, are then used to frequency encode the position of the receive coil(s). Data are Fourier transformed and one or more peaks located to determine the position of each receiver coil in the direction of the applied field gradient. Subsequent data collected on orthogonal axes permits the localization of the receiver coil in three dimensions. The process can be repeated rapidly and the position of each coil can be displayed in real-time.
518 citations
"Acousto-Optic Catheter Tracking Sen..." refers background in this paper
...[11], usually in small coil form, to collect localized RF signal [12]....
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