Tactile Sensing System for Lung Tumour Localization during Minimally Invasive Surgery

Video-assisted thoracoscopie surgery (VATS) is becoming a prevalent method for lung cancer treatment. However, VATS suffers from the inability to accurately relay haptic information to the surgeon, often making tumour localization difficult. This limitation was addressed by the design of a tactile sensing system (TSS) consisting of a probe with a tactile sensor and interfacing visualization software. In this thesis, TSS performance was tested to determine the feasibility of implementing the system in VATS. This was accomplished through a series of ex vivo experiments in which the tactile sensor was calibrated and the visualization software was modified to provide haptic information visually to the user, and TSS performance was compared using human and robot palpation methods, and conventional VATS instruments. It was concluded that the device offers the possibility of providing to the surgeon the haptic information lost during surgery, thereby mitigating one of the current limitations of VATS

Polyvinylidene fluoride - based MEMS tactile sensor for minimally invasive surgery

Minimally invasive surgery (MIS) procedures have been growing rapidly for the past couple of decades. In MIS operations, endoscopic tools are inserted through a small incision on human's body. Although these procedures have many advantages such as fast recovery time, minimum damage to human body and reduced post operative complications, it does not provide any tactile feedback to the surgeon. This thesis reports on design, finite element analysis, fabrication and testing of a micromachined piezoelectric endoscopic tactile sensor. Similar to the commercial endoscopic graspers, the sensor is teeth like in order to grasp slippery tissues. It consists of three layers; the first layer is a silicon layer of teeth shapes on the top and two supports at the bottom forming a thin plate and a U-Channel. The second layer is a patterned Polyvinylidene Fluoride (PVDF) film, and the third layer is a supporting Plexiglas. The patterned PVDF film was placed on the middle between the other two layers. When a concentric load is applied to the sensor, the magnitude and the position of the applied load are obtained from the outputs of the sensing elements which are sandwiched between the silicon supports and the Plexiglas. In addition, when a soft object/tissue is place on the sensor and load is applied the degree of the softness/compliance of the object is obtained from the outputs from the middle PVDF sensing elements, which are glued to the back of the thin silicon plate. The outputs are related to the deformation of the silicon plate which related to the contacting object softness. The sensor has high sensitivity and high dynamic range as a result it can potentially detect a small dynamic load such as a pulse load as well as a high load such as a firm grasping of a tissue by an endoscopic grasper. The entire surface of the tactile sensor is also active, which is an advantage in detecting the precise position of the applied point load on the grasper. The finite element analysis and experimental results are in close agreement with each other. The sensor can potentially be integrated with the gasper of a commercially available endoscopic graspe

Validation of a Sensorized Instrument-Based Training System for Minimally Invasive Surgery

Minimally invasive surgery training is complicated by the restraints imposed by the surgical environment. A sensorized laparoscopic instrument capable of sensing force in 5 degrees of freedom and position in 6 degrees of freedom was evaluated. Novice and Expert laparoscopists performed a complex minimally invasive surgical task - suturing - using the novel instruments. Their force and position profiles were compared. The novel minimally invasive surgical instrument is construct-valid and capable of detecting differences between novices and experts in a laparoscopic suturing task with respect to force and position. It is also concurrently valid with an existing standard: the Fundamentals of Laparoscopic Skills. Further evaluation is mandated to better understand the ability to predict performance based on force and position as well as the potential for new metrics in minimally invasive surgical education

MEMS Technology for Biomedical Imaging Applications

Biomedical imaging is the key technique and process to create informative images of the human body or other organic structures for clinical purposes or medical science. Micro-electro-mechanical systems (MEMS) technology has demonstrated enormous potential in biomedical imaging applications due to its outstanding advantages of, for instance, miniaturization, high speed, higher resolution, and convenience of batch fabrication. There are many advancements and breakthroughs developing in the academic community, and there are a few challenges raised accordingly upon the designs, structures, fabrication, integration, and applications of MEMS for all kinds of biomedical imaging. This Special Issue aims to collate and showcase research papers, short commutations, perspectives, and insightful review articles from esteemed colleagues that demonstrate: (1) original works on the topic of MEMS components or devices based on various kinds of mechanisms for biomedical imaging; and (2) new developments and potentials of applying MEMS technology of any kind in biomedical imaging. The objective of this special session is to provide insightful information regarding the technological advancements for the researchers in the community

Optical Microsystems for Static and Dynamic Tactile Sensing: Design, Modeling, Fabrication and Testing

Minimally invasive surgical operations encompass various surgical tasks ranging from conventional endoscopic/laparoscopic methods to recent sophisticated minimally invasive surgical techniques. In such sophisticated techniques, surgeons use equipment varying from robotic-assisted surgical platforms for abdominal surgery to computer-controlled catheters for catheter-based cardiovascular surgery. Presently, the countless advantages that minimally invasive surgery offers for both patients and surgeons have made the use of such surgical operations routine and reliable. However, in such operations, unlike conventional surgical operations, surgeons still suffer from the lack of tactile perception while interacting with the biological tissues using surgical instruments. To address this issue, it is necessary to develop a tactile sensor that can mimic the fingertip tactile perceptions of surgeons. In doing so and to satisfy the needs of surgeons, a number of considerations should be implemented in the design of the tactile sensors. First, the sensor should be magnetic resonance compatible to perform measurements even in the presence of magnetic resonance imaging (MRI) devices. Currently, such devices are in wide-spread use in surgical operation rooms. Second, the sensor should be electrically-passive because introducing electrical current into the patients’ body is not desirable in various surgical operations such as cardiovascular operations. Third, the sensor should perform measurements under both static and dynamic loading conditions during the sensor-tissue interactions. Such a capability of the sensor ensures that surgeons receive tactile feedback even when there is continuous static contact between surgical tools and tissues. Essentially, surgeons need such feedback to make surgical tasks safer. In addition, the size of the sensor should be miniaturized to address the size restrictions. In fact, the combination of intensity-based optical fiber sensing principles and micro-systems technology is one of the limited choices that address all the required considerations to develop such tactile sensors in a variety of ways. The present thesis deals with the design, modeling, manufacturing, testing, and characterizing of different tactile sensor configurations based on detection and integration methods. The various stages of design progress and principles are developed into different design configurations and presented in different chapters. The main sensing principle applied is based on the intensity modulation principle of optical fibers using micro-systems technology. In addition, a hybrid sensing principle is also studied by integrating both optical and non-optical detection methods. The micromachined sensors are categorized into five different generations. Each generation has advantages by comparison with its counterpart from the previous generation. The initial development of micromachined sensors is based on optical fiber coupling loss. In the second phase, a hybrid optical-piezoresistive sensing principle is studied. The success of these phases was instrumental in realizing a micromachined sensor that has the advantage of being fully optical. This sensor measures the magnitude of concentrated and distributed force, the position of a concentrated force, the variations in the force distribution along its length, the relative hardness of soft contact objects, and the local discontinuities in the hardness of the contact objects along the length of the contact area. Unlike most electrical-based commercially-available sensors, it performs all of these measurements under both static and dynamic loading conditions. Moreover, it is electrically passive and potentially MRI-compatible. The performances of the sensors were experimentally characterized for specific conditions presented in this thesis. However, these performances are easily tunable and adjustable depending upon the requirements of specific surgical tasks. Although the sensors were initially designed for surgical applications, they can have numerous other applications in the areas of robotics, automation, tele-display, and material testing

Looking Forward with Minimally Invasive Ultrasound

Minimally invasive procedures are increasingly replacing traditional open surgeries due to their shorter recovery time, reduced patient pain, reduced risk of infection and less trauma. However, since the physician has no direct view of the working field, visualization of these complex interventions is critical for success. Forward-looking (FL) ultrasound image guidance can aid minimally invasive procedures providing visual feedback of the working field, instrument location and treatment progress. Currently there are no clinically available devices that can provide minimally invasive 3D FL imaging. In this thesis we explored several innovative solutions towards miniaturized 3D FL imaging. We looked into methods to solve both hardware and image-related challenges resulting in mainly two approaches. The first approach consists in the realization of a complex multi-element transducer with an optimized design and an efficient interconnection and integration scheme. The second approach consists in the use of s

Medical Robotics

The first generation of surgical robots are already being installed in a number of operating rooms around the world. Robotics is being introduced to medicine because it allows for unprecedented control and precision of surgical instruments in minimally invasive procedures. So far, robots have been used to position an endoscope, perform gallbladder surgery and correct gastroesophogeal reflux and heartburn. The ultimate goal of the robotic surgery field is to design a robot that can be used to perform closed-chest, beating-heart surgery. The use of robotics in surgery will expand over the next decades without any doubt. Minimally Invasive Surgery (MIS) is a revolutionary approach in surgery. In MIS, the operation is performed with instruments and viewing equipment inserted into the body through small incisions created by the surgeon, in contrast to open surgery with large incisions. This minimizes surgical trauma and damage to healthy tissue, resulting in shorter patient recovery time. The aim of this book is to provide an overview of the state-of-art, to present new ideas, original results and practical experiences in this expanding area. Nevertheless, many chapters in the book concern advanced research on this growing area. The book provides critical analysis of clinical trials, assessment of the benefits and risks of the application of these technologies. This book is certainly a small sample of the research activity on Medical Robotics going on around the globe as you read it, but it surely covers a good deal of what has been done in the field recently, and as such it works as a valuable source for researchers interested in the involved subjects, whether they are currently “medical roboticists” or not

A Sensorized Instrument for Minimally Invasive Surgery for the Measurement of Forces during Training and Surgery: Development and Applications

The reduced access conditions present in Minimally Invasive Surgery (MIS) affect the feel of interaction forces between the instruments and the tissue being treated. This loss of haptic information compromises the safety of the procedure and must be overcome through training. Haptics in MIS is the subject of extensive research, focused on establishing force feedback mechanisms and developing appropriate sensors. This latter task is complicated by the need to place the sensors as close as possible to the instrument tip, as the measurement of forces outside of the patient\u27s body does not represent the true tool--tissue interaction. Many force sensors have been proposed, but none are yet available for surgery. The objectives of this thesis were to develop a set of instruments capable of measuring tool--tissue force information in MIS, and to evaluate the usefulness of force information during surgery and for training and skills assessment. To address these objectives, a set of laparoscopic instruments was developed that can measure instrument position and tool--tissue interaction forces in multiple degrees of freedom. Different design iterations and the work performed towards the development of a sterilizable instrument are presented. Several experiments were performed using these instruments to establish the usefulness of force information in surgery and training. The results showed that the combination of force and position information can be used in the development of realistic tissue models or haptic interfaces specifically designed for MIS. This information is also valuable in order to create tactile maps to assist in the identification of areas of different stiffness. The real-time measurement of forces allows visual force feedback to be presented to the surgeon. When applied to training scenarios, the results show that experience level correlates better with force-based metrics than those currently used in training simulators. The proposed metrics can be automatically computed, are completely objective, and measure important aspects of performance. The primary contribution of this thesis is the design and development of highly versatile instruments capable of measuring force and position during surgery. A second contribution establishes the importance and usefulness of force data during skills assessment, training and surgery

Design and implementation of intravascular hifu catheter ablation system

High-intensity focused ultrasound is an energy-based thermal therapy for noninvasive or minimally invasive treatment of wide range of medical disorders including solid cancer tumors, brain surgery, atrial fibrillation (AF) and other cardiac arrhythmias. Conventional HIFU is extracorporeally administered but in applications where a small lesion or more precise energy localization in shorter time is required, catheter-based HIFU devices which are positioned directly within or adjacent to the target may be the best solution. Available HIFU catheters use array of piezoelectric transducers with complex external high-voltage (HV) and high-frequency amplifiers, a cooling system and several coaxial cables within the catheter. In this study, a HV transmitter IC has been designed, manufactured and integrated with an 8-element capacitive micromachined ultrasound transducer (CMUT) on a prototype HIFU probe appropriate for a 6-Fr catheter. The transmitter IC fabricated in 0.35 μm HV CMOS process and comprises eight continuouswave HV buffers (10.9 ns and 9.4 ns rise and fall times at 20 Vpp output into a 15 pF), an eight-channel transmit beamformer (8-12 MHz output frequency with 11.25 º phase accuracy) and a phase locked loop with an integrated VCO as a tunable clock source (128–192 MHz). The chip occupies 1.85×1.8 mm2 area including input and output (I/O) pads. Electrical measurements, IR thermography and Ex-vivo experiment results reveal that the presented HIFU system can elevate the temperature of the target region of tissue around 19 ºC by delivering 600 CEM43 equivalent thermal dose while surface temperature of the probe rises less than 5 º