Investigating the Feasibility of Using Focussed Airborne Ultrasound as Tactile Feedback in Medical Simulators

Novice medical practitioners commonly practice on live patients in real medical procedures. However, due to the inexperience of the practitioner, mistakes are likely which exposes the patient to undue risk. To improve the training of novices, medical simulators create a virtual patient providing a safe environment for the user to practice within. An important clinical skill is palpation, a physical examination technique. The practitioners use their hands to feel the body of the patient to make diagnosis. A virtual patient has a visual representation but as it is virtual, the patient is not physically present. Haptics technology provide additional benefits to the training session by stimulating the physical sense of touch. A novel technique has recently emerged for stimulating tactile sensation called acoustic radiation pressure from focussed airborne ultrasound. Acoustic radiation creates a focal point of concentrated acoustic pressure in a three-dimensional field producing a force in mid-air. Airborne ultrasound has several advantages over conventional technologies. It was also initially theorised that using airborne ultrasound to simulate palpation compared to a previous system called PalpSim which consists of a rubber tube filled with water permanently embedded in a block of silicone, will offer better controllability over the displayed sensation to simulate various tactile sensations. The thesis has investigated the feasibility of using focussed airborne ultrasound as tactile feedback in medical simulators. A tactile device called UltraSendo was completely custom built to simulate an arterial pulse and a thrill sensation. UltraSendo was integrated with an augmented reality simulator displaying a virtual patient for user interaction. The simulator was brought to Ysbyty Glan Clwyd hospital for user feedback. A wide range of user responses were gathered. The majority of responses felt the arterial pulse was not sufficiently realistic whilst there were higher ratings for the thrill sensation which is acceptably realistic. Positive feedback suggests that airborne ultrasound can indeed provide tactile feedback in a medical context and is better at simulating a thrill sensation compared to a pulse sensation

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

A Soft touch: wearable dielectric elastomer actuated multi-finger soft tactile displays

PhDThe haptic modality in human-computer interfaces is significantly underutilised when compared to that of vision and sound. A potential reason for this is the difficulty in turning computer-generated signals into realistic sensations of touch. Moreover, wearable solutions that can be mounted onto multiple fingertips whilst still allowing for the free dexterous movements of the user’s hand, brings an even higher level of complexity. In order to be wearable, such devices should not only be compact, lightweight and energy efficient; but also, be able to render compelling tactile sensations. Current solutions are unable to meet these criteria, typically due to the actuation mechanisms employed. Aimed at addressing these needs, this work presents research into non-vibratory multi-finger wearable tactile displays, through the use of an improved configuration of a dielectric elastomer actuator. The described displays render forces through a soft bubble-like interface worn on the fingertip. Due to the improved design, forces of up to 1N can be generated in a form factor of 20 x 12 x 23 mm, with a weight of only 6g, demonstrating a significant performance increase in force output and wearability over existing tactile rendering systems. Furthermore, it is shown how these compact wearable devices can be used in conjunction with low-cost commercial optical hand tracking sensors, to cater for simple although accurate tactile interactions within virtual environments, using affordable instrumentation. The whole system makes it possible for users to interact with virtually generated soft body objects with programmable tactile properties. Through a 15-participant study, the system has been validated for three distinct types of touch interaction, including palpation and pinching of virtual deformable objects. Through this investigation, it is believed that this approach could have a significant impact within virtual and augmented reality interaction for purposes of medical simulation, professional training and improved tactile feedback in telerobotic control systems.Engineering and Physical Sciences Research Council (EPSRC) Doctoral Training Centre EP/G03723X/

Recent advances in biomedical photonic sensors: a focus on optical-fibre-based sensing

In this invited review, we provide an overview of the recent advances in biomedical pho tonic 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.This work was supported by Ministerio de Ciencia e Innovación and Agencia Estatal de Investigación (PID2019-107270RB-C21/AEI/10.13039/501100011033), and TeDFeS Project (RTC-2017- 6321-1) co-funded by European FEDER funds. M.O. and J.F.A. received funding from Ministerio de Ciencia, Innovación y Universidades of Spain under Juan de la Cierva-Formación and Juan de la Cierva-Incorporación grants, respectively. P.R-V. received funding from Ministerio de Educación, Cultura y Deporte of Spain under PhD grant FPU2018/02797

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

Multimodal and multiscale imaging of the human placental vasculature

Minimally invasive fetal interventions, such as those used for therapy of twin-to- twin transfusion syndrome (TTTS), require accurate image guidance to optimise patient outcomes. Photoacoustic imaging can provide molecular contrast based on the optical absorption of the haemoglobin, and in this dissertation, it was proposed as a novel technique to image the human placental vasculature. Normal term and in utero TTTS treated placentas were imaged post-partum using two novel photoacoustic imaging systems. With PA imaging, vasculature was resolved to a depth of approximately 7 mm from the chorionic placental surface; the photocoagulated tissue provided a negative contrast and the ablation depth of the scar was visualised. Complementary imaging of the placental vasculature in a microscopic size scale was performed with a handheld incident dark field illumination video microscope in fresh and formalin-fixed term placentas. Real time visualisation of the villus tree down to the terminal villi level was achieved without any contrast injection or extensive tissue preparation. Additionally, the novel application of photoacoustic imaging to guide minimally invasive fetal interventions motivated the development of tissue-mimicking placental phantoms for bench-top system validation and for clinical training. Ideally, phantoms for this modality comprise materials with optical and acoustic properties that can be precisely and independently controlled, which are stable over time, and which are non-toxic and low-cost. Gel wax was proposed as a novel tissue-mimicking material (TMM) that satisfies these criteria, and that it can be used to represent various soft tissues and fabricate heterogeneous phantoms with structures based on patient-specific anatomy. This dissertation sets the stage for the development of miniaturised photoacoustic imaging probes for intraoperative guidance, and new methods of understanding the placental vascular anatomy in health and disease. Gel wax has strong potential to become a next generation TMM for evaluation, and standardisation of imaging systems, and for clinical training

Liver Biopsy

Liver biopsy is recommended as the gold standard method to determine diagnosis, fibrosis staging, prognosis and therapeutic indications in patients with chronic liver disease. However, liver biopsy is an invasive procedure with a risk of complications which can be serious. This book provides the management of the complications in liver biopsy. Additionally, this book provides also the references for the new technology of liver biopsy including the non-invasive elastography, imaging methods and blood panels which could be the alternatives to liver biopsy. The non-invasive methods, especially the elastography, which is the new procedure in hot topics, which were frequently reported in these years. In this book, the professionals of elastography show the mechanism, availability and how to use this technology in a clinical field of elastography. The comprehension of elastography could be a great help for better dealing and for understanding of liver biopsy

Contextualising simulation: the use of patient-focused hybrid simulation for clinical skills education

This thesis documents a research programme into the use of Patient-Focused Hybrid Simulation (PFHS) for clinical skills education. PFHS is an approach to simulating clinical skills that combines a simulated patient (SP) with a part-task trainer (PTT) embedding the simulation of procedural skills within a more holistic clinical context, potentially overcoming some of the shortcomings of single modality simulation. Although promising, there remains limited evidence supporting its use. Two studies were conducted using a mixed-method approach. The first study was based on the simulation of the management of a traumatic skin laceration and consisted of two parts: 1) investigating the use of PFHS as a means of introducing clinical challenge by modifying the clinical context in which a procedure is performed; 2) exploring clinician’s perception of the use of PFHS and PTT for assessing of clinical competence. These findings suggest that by changing the clinical context in which a procedure is performed, PFHS can potentially be used to objectively simulate challenge. It also demonstrated that PFHS when compared to PTT simulations was better able to induce authentic clinical behaviour within the simulation. Central to this is the presence of a human being (SP). The second study compared the use of PFHS to patients for the training and assessment of cardiovascular examination skills. Within the limitations of this study, no significant difference was observed between PFHS and real patient-trained students in terms of their post-training performance of cardiovascular examination on real patients. There also appeared to be degree of concurrent validity between assessment of competency with PFHS and with real patients when conducted as an Objective Structured Clinical Examination (OSCE). The work presented provides additional evidence to the existing literature to support the use of PFHS in clinical skills education. However, it also raises a multitude of questions particularly of how PFHS as well as simulation in general should be used and future directions for simulation research.Open Acces