Design of ASIC Based Electrical Impedance Tomography Microendoscopic System for Prostate Cancer Surgical Marginal Assessment

Prostate cancer is the second most common cancer in the United States. It is typically treated by surgically excising the cancerous section of the prostate. Because there is not always a visible distinction between the healthy and cancerous sections, surgery often leaves some cancerous tissue behind. This is referred to as a positive surgical margin and it requires adjuvant treatment with adverse side effects. Electrical impedance tomography (EIT) is a low-cost low-form-factor method that can be used to assess surgical marginal intraoperatively to ensure that no cancerous tissue is left behind. EIT-based surgical margin assessment works on the principle that the electrical properties of cancerous tissue are different from those of healthy tissue. These differences are small at lower frequencies but become more pronounced at frequencies of 1 MHz and higher. Unfortunately, previous EIT solutions for surgical marginal assessment have been limited to operating frequencies of less than 1 MHz. This thesis presents a custom application-specific integrated circuit (ASIC) analog front end for performing EIT with a signal-to-noise ratio of 75 dB up to an operating frequency of 10 MHz. The custom ASIC was integrated into a 16-electrode EIT system for surgical marginal assessment. The entire system was tested on a saline phantom with a 2 mm bead that represented a cancerous lesion. The EIT system produced single-frequency and multi-frequency images showing the presence of the inclusion

Energy-Efficient PRBS Impedance Spectroscopy on a Digital Versatile Platform

partially_open6siThis research has been partially funded by the Italian Ministry of University and Research (MUR) through the program “Dipartimenti di Eccellenza” (2018-2022). The research has also received partial support from the Italian Ministry of University and Research (MUR) and the Eranet FLAG ERA initiative within CONVERGENCE project (CUP B84I16000030005) through the IUNET Consortium.This paper presents the digital design of a versatile and low-power broadband impedance spectroscopy (IS) system based on pseudo-random binary sequence (PRBS) excitation. The PRBS technique allows fast, and low-power estimation of the impedance spectrum over a wide bandwidth with adequate accuracy, proving to be a good candidate for portable medical devices, especially. This paper covers the low-power design of the firmware algorithms and implements them on a versatile and reconfigurable digital platform that can be easily adjusted to the specific application. It will analyze the digital platform with the aim of reducing power consumption while maintaining adequate accuracy of the estimated spectrum. The paper studies two main algorithms (time-domain and frequency-domain) used for PRBS-based IS and implements both of them on the ultra-low-power GAP-8 digital platform. They are compared in terms of accuracy, measurement time, and power budget, while general design trade-offs are drawn out. The time-domain algorithm demonstrated the best accuracy while the frequency-domain one contributes more to save power and energy. However, analysis of the energy-per-error FOM revealed that the time-domain algorithm outperforms the frequency-domain algorithm offering better accuracy for the same energy consumption. Numerical methods and microprocessor resources are exploited to optimize the implementation of both algorithms achieving 27 ms in processing time, power consumption as low as 1.4 mW and a minimum energy consumption per measurement of 0.5 mJ, for a dense impedance spectrum estimation of 214 points.embargoed_20210525Luciani G.; Crescentini M.; Romani A.; Chiani M.; Benini L.; Tartagni M.Luciani G.; Crescentini M.; Romani A.; Chiani M.; Benini L.; Tartagni M

Ultra-Low-Power Sensors and Receivers for IoT Applications

The combination of ultra-low power analog front-ends and CMOS-compatible transducers enable new applications, such as environmental monitors, household appliances, health trackers, etc. that are seamlessly integrated into our daily lives. Furthermore, wireless connectivity allows many of these sensors to operate both independently and collectively. These techniques collectively fulfil the recent surge of internet-of-things (IoT) applications that have the potential to fundamentally change daily life for millions of people.In this dissertation, the circuit and system design of wireless receivers and sensors is presented that explores the challenges of implementing long lifespan, high accuracy, and large coverage range IoT sensor networks. The first is a wake-up receiver (WuRX), which continuously monitors the RF environment to wake up a higher-power radio upon detection of a predetermined RF signature. This work both improves sensitivity and reduces power over prior art through a multi-faceted design featuring an impedance transformation network with large passive voltage gain, an active envelope detector with high input impedance to facilitate large passive voltage gain, a low-power precision comparator, and a low-leakage digital baseband correlator.Although pushing the prior WuRX performance boundary by orders of magnitude, the first work shows moderate sensitivity, inferior temperature robustness, and large area with external lumped components. Thus, the second work shows a miniaturized WuRX that is temperature-compensated, yet still consumes only nano-watt power and millimeter area while operating at 9 GHz. To further reduce the area, a global common-mode feedback is utilized across the envelope detector and baseband amplifier that eliminates the need for off-chip ac-coupling components. Multiple temperature-compensation techniques are proposed to maintain constant bandwidth of the signal path and constant clock frequency. Both WuRXs operate at 0.4 V supply, consume near-zero power and achieve ~-70 dBm sensitivity.Lastly, the first reported CMOS 2-in-1 relative humidity and temperature sensor is presented. A unified analog front-end interfaces on-chip transducers and converts the inputs into a frequency vis a high-linearity frequency-locked loop. An incomplete-settling switched-capacitor-based Wheatstone bridge is proposed to sense the inputs in a power-efficient fashion

Imaging Sensors and Applications

In past decades, various sensor technologies have been used in all areas of our lives, thus improving our quality of life. In particular, imaging sensors have been widely applied in the development of various imaging approaches such as optical imaging, ultrasound imaging, X-ray imaging, and nuclear imaging, and contributed to achieve high sensitivity, miniaturization, and real-time imaging. These advanced image sensing technologies play an important role not only in the medical field but also in the industrial field. This Special Issue covers broad topics on imaging sensors and applications. The scope range of imaging sensors can be extended to novel imaging sensors and diverse imaging systems, including hardware and software advancements. Additionally, biomedical and nondestructive sensing applications are welcome

A New Versatile Electronic Speckle Pattern Interferometer For Vibration Measurements

Electronic speckle pattern interferometry (ESPI) has been widely used for vibration amplitude and phase measurements. Conventional ESPI systems are bulk and expensive and need careful alignment of all the optical components which is a time consuming task. To overcome these problems alternative compact ESPI systems were developed using fibre-optical components or holographic optical elements (HOEs). The fibre-optic based ESPI systems suffer from random phase fluctuations induced by environmental temperature changes. Hence HOEs can be used as more powerful alternative optical elements to design ESPI systems. The time average ESPI method is widely used for vibration studies. The time average method combined with phase stepping can be used for automatic vibration measurements. Using this technique higher vibration amplitudes cannot be measured because fringe patterns follow Bessel function intensity distribution. To overcome this problem an alternative technique can be used by modulating the phase of the reference beam in an unbalanced interferometer. This thesis reports a novel ESPI system for vibration measurements by combining use of holographic optical elements (HOEs) and optical path length modulation (reference beam phase modulation). The optical path length modulation is implemented using laser diode wavelength (frequency) modulation. Different HOE based ESPI systems are reported in this thesis using either a single HOE or dual HOE. This thesis examines performance of different HOE based ESPI systems that are sensitive to out-of-plane displacement components using laser diodes operating either in the near infrared or visible electromagnetic spectrum. Vibration modes of a circular metal plate clamped at the edges of a loud speaker and a circular metal plate driven by a piezoelectric actuator (PZT) were studied using a single RHOE based ESPI system and a hybrid (transmission HOE with a partially reflecting mirror) HOE based ESPI system respectively using a near infrared laser diode (763nm). Optical path length modulation technique was implemented using a laser diode operating in visible electromagnetic spectrum (658nm). Vibration mode patterns of a circular metal plate driven by a PZT actuator were obtained using both single RHOE and dual HOE based ESPI systems. Using optical path length modulation technique in a dual HOE based ESPI system detailed phase and amplitude maps of a circular metal plate driven by a PZT actuator are obtained. The dual HOE based ESPI system was also used for measuring roations of a circular metal plate mounted on a mirror mount. In conclusion we have developed a compact HOE based ESPI system to conduct vibration measurements. A few potential future developments are also suggested at the end of the thesis

Automated tracking of the Florida manatee (Trichechus manatus)

The electronic, physical, biological and environmental factors involved in the automated remote tracking of the Florida manatee (Trichechus manatus) are identified. The current status of the manatee as an endangered species is provided. Brief descriptions of existing tracking and position locating systems are presented to identify the state of the art in these fields. An analysis of energy media is conducted to identify those with the highest probability of success for this application. Logistic questions such as the means of attachment and position of any equipment to be placed on the manatee are also investigated. Power sources and manateeborne electronics encapsulation techniques are studied and the results of a compter generated DF network analysis are summarized

Modeling EMI Resulting from a Signal Via Transition Through Power/Ground Layers

Signal transitioning through layers on vias are very common in multi-layer printed circuit board (PCB) design. For a signal via transitioning through the internal power and ground planes, the return current must switch from one reference plane to another reference plane. The discontinuity of the return current at the via excites the power and ground planes, and results in noise on the power bus that can lead to signal integrity, as well as EMI problems. Numerical methods, such as the finite-difference time-domain (FDTD), Moment of Methods (MoM), and partial element equivalent circuit (PEEC) method, were employed herein to study this problem. The modeled results are supported by measurements. In addition, a common EMI mitigation approach of adding a decoupling capacitor was investigated with the FDTD method

13th Annual Review of Progress in Applied Computational Electromagnetics at the Naval Postgraduate School, Monterey, CA, March 17-21, 1997, Conference Proceedings Volumes I & II

Includes Volumes 1 &