Endovascular surgery is a relatively new, rapidly growing, clinical technique and research area. A new endovascular tool has been developed by Endovascular Development AB, the Liungman Guidewire Fixator (LGF) that secures the distal position of a guidewire. The design of the LGF resembles a nitinol (Nickel-Titanium) stent and exerts a radial force against the blood vessel wall. It is desirable to have a well-founded understanding of all the mechanical characteristics of the product from a medical technology safety perspective.   There are different methods for uniformly measure the radial force of an object, i.e. where one single total radial force represents the entire object. This report investigates the possibility for segmented radial force measurement by the development of a new measuring instrument. A prototype of the measuring instrument has been produced to test if the proposed method can be implemented or not.   The prototype has been designed, developed and constructed to measure the radial force of individual segments of the stent. The stent segments were created using iris diaphragms and their resistance to radial change were measured using strain gauges. The concept was to measure the radial force differences between each segment with respect to the diameter of the stent. The results show a large and high intensity variation of data due to the strain gauge application. The variation is due to disturbances and flaws in the manufacturing process. On the other hand, one can see that the values for the radial forces of the segments for them different LGFs provide reasonable magnitudes. Some experiments also presents results similar to previous experiments. However, at the same time, no statistically significant conclusion can be drawn. The concept and the theory should work if the errors are changed. In summary, the proposal is to further develop the prototype and complement the experiment using finite element analysis.

Background: Approximately 67% of lower limb amputees fall once or more every year. It is important for their daily functioning and their social life that their prosthetic device provide them with stability and security. Measuring stability for amputees and their prosthetic devices is challenging, especially for amputees with low activity level. However, it is important for the users and the product designers to know if the products are actually providing the user with more stability. Objective: The aim of the study is to create a measurement protocol to quantify static and dynamic stability with enough sensitivity to differentiate between two prosthetic products for amputees with low activity level. Methods: Ten K2, unilateral transtibial subjects were recruited and 6 of them completed the protocol during a 2-hour visit. They repeated the same protocol for two prosthetic feet, K2C (Össur, Iceland) and K2 Sensation (Össur, Iceland). In order to compare the static and dynamic stability of the subjects and the products, three different tests and one questionnaire were used: Static standing test, Limit of Stability (LOS) test, Walking on level ground, and the Activities-specific Balance Confidence scale (ABC scale). Results: For the static standing test, the K2Sensation showed less range for the center of pressure in the anteroposterior direction while standing in a normal position with the eyes open. However, the participants were able to reach further (LOS test) over their prosthetic side while wearing the K2C foot. For the K2C foot, gait parameters such as ankle power, positive work, self selected walking speed and the range of motion in the prosthetic ankle all increased. The backward margin of stability (BwMOS) only increased for 2 participants who had it in common to both wear ProFlex-XC in daily life. No difference was seen in perceived stability according to the ABC scale. Conclusion: The aim of the study was reached. Static and dynamic stability were quantified and distinguished between the 2 different prosthetic feet. It is concluded that both the static standing test and the LOS test are necessary parts of the protocol as they capture different aspects of static stability. For future studies, a longer adaptation time is suggested for the participants to achieve a stable gait pattern and to answer the ABC scale with more reliability / Bakgrund: Cirka 67% av patienter som amputerat ett eller både ben ramlar minst en gång varje år. En protesfot som förser dem med stabilitet och säkerhet är viktigt för den dagliga funktionen och socialsamvaron. Det är en stor utmaning att mäta protesstabilitet, särskilt för patienter med en relativt låg aktivitetsnivå. Det är dock viktigt för både dem och för tillverkarna med relevant information om huruvida protesen ökar patienternas stabilitet, både objektivt och subjektivt. Syfte: Syftet med studien är att skapa ett experimentellt protokoll för att kvantitativt mäta statisk och dynamisk stabilitet. Protokollet bör vara tillräcklig känsligt för att kunna urskilja mellan två protesdesign hos amputerade med låg aktivitetsnivå. Metoder: Tio st. K2 patienter med unilateral transtibial amputation rekryterades, av dem 6 kunde fullfölja experimentet under ett två timmars besök. Samma experimentell procedur upprepades med två protesfötter, K2C (Össur, Island) och K2 Sensation (Össur, Island), i en randomiserade ordning. Tre experimentella test och ett frågeformulär användes för att jämföra statisk och dynamisk stabilitet: Static standing test, Limit of Stability (LOS)- test, Walking on level ground, samt Activities-specific Balance Conidence scale (ABC-skala). Resultat: Under statiska stående i en normal position med öppna ögon, kunde patienterna nå mindre sina Center of Pressure (COP) i anteroposterior riktningen med K2Sensation än med K2C. Deltagarna kunde dock luta mera (LOStest) över sina K2C-fötter än över sina K2Sensation-fötter. Med K2C-foten ökade temporospatiala gångparametrar såsom fotledseffekt, positivt fotledsarbete, självvald gånghastighet och dynamiskt rörelseomfång hos protesfoten. Backwards Margin of Stability (BwMOS) ökade med K2C-foten enbart hos 2 deltagare, som både använder vanligtvis en ProFlex-XC fot. Ingen skillnad i den subjektiva upplevelsen av stabilitet enligt ABC-skalan har visats. Slutsats: Syftet med studien uppnåddes; statisk och dynamisk stabilitet kunde kvantifieras och urskiljes mellan de två olika protetiska fötter. Slutsatsen är att både statiska test och dynamiska (t.ex LOS-testet) behövs eftersom de fångar olika aspekter av stabilitet när man står. För att öka tillförlitlighet i både experimentella parametrar samt i ABC-skalan, samt för att ge patienterna möjlighet att arbeta fram ett stabilt gångmönster med en ny protesfot, förslås i framtida studier att patienterna får en längre anpassningstid före undersökningen.

The need for efficient solutions in healthcare is clearly evident with the issue of hospitalovercrowding, the increasing shortage of trained personnel, and an aging population. Toaddress these challenges, the government has decided to invest in digital aids. Inresponse to this need, the Swift Vitals project has been initiated through collaborationwith the company Stixon AB. The concept enables a smooth and continuousmeasurement process that promotes proactive healthcare. The time-saving measurementprocess provides significantly more data in the form of health metrics. By analyzingtrends, healthcare professionals can take early action and thereby avoid acute care forpatients, which benefits a more proactive care environment.The assignment included the development of a concept consisting of three components:a sensor unit, a web application, and a database. The project has focused on carerecipients with cognitive impairment and has involved extensive information gatheringin consultation with professors from the university, the Leap For Life organization, andthe healthcare sector in Halland. An extensive feasibility study was conducted, whichinvolved visits to various care facilities and interviews with 25 individuals within thehealthcare sector. This feasibility study formed the basis of the project. During thedevelopment process, two students from KTH were involved, tasked with programmingthe web application and the database.The result was a fully functioning prototype with the potential for implementation inhealthcare. The prototype consists of a portable sensor unit that measures relevanthealth parameters for the target group. The sensor unit transmits the measurement datato the web application through a Wi-Fi connection. The web application offershealthcare professionals opportunities to visualize trends in historical measurementdata, along with other user-friendly features. All data is managed and stored in adatabase.This prototype has the potential to contribute to the efficiency of healthcare throughearly intervention and more informed decision-making. With strong conviction, theproject team envisions a bright and promising future for Swift Vitals.

Driver distraction is a contributing factor to car accidents here a warning system could potentially prevent some of these accidents by making the driver aware of distraction and redirecting the focus back to driving-related activities. The purpose of this work is to better understand where drivers direct their attention while driving and where the attention should be directed for the driver to be considered attentive. For this, zones determining where the driver is looking were created. This project aimed to analyze how drivers direct their gaze when approaching different types of intersections with different types of features, and after that use this data to create zones for where a driver should have looked before crossing each type of intersection to be considered attentive to driving. The data used in this project was received from Smart Eye AB in Gothenburg. Data were collected from 38 subjects driving a route in the city of Gothenburg while eye tracking and GPS data were sampled. These data sets were preprocessed and then combined into one set of data. This combined data set was used to analyze drivers' glance behavior in different types of intersections (three-way intersections, four-way intersections, roundabouts, and motorway junctions) with different features, such as pedestrian crossings, traffic lights, yield signs, etc. The most rewarding results were obtained from the three-way and four-way intersections where the driver makes a turn in the intersection. It was established that when approaching an intersection the proportion of glances in the forward zone decreases. In contrast, the ratio of glances in the left, right, outside left, and outside right zones increases. This could be interpreted as a need for attention to be directed here. The conclusion was that the work done in this project has great potential to become useful in the further development of a driver distraction algorithm for implementation in future car models to prevent accidents from occurring because of driver inattention.

The usage of ultrasonic manipulation of cells enables a more in vivo-like study with maintained cell viability compared to ordinary systems based on 2D manipulation. The method can be applied for cell trapping and micro tissue engineering and has applications for medical and biological studies.   The current system used at the Department of Applied Physics, Royal Institute of Technology, needs characterization and optimization regarding its subsystems. This thesis has studied the setup in order to map the origins of heat generation, to improve the system arrangement. As a result, an overview of affecting factors has been presented. The thesis is based on temperature and bead measurements with and without the use of an impedance matching circuit and with/without amplifiers. It was found that the system could be optimized with a smaller and less expensive amplifier reducing the overall system costs. The thesis also resulted in a proposition for further work to optimize the system with respect to its subsystems.

Abstract Fall accidents leads to an average of three deaths a day in Sweden. The high mortality and morbidity associated with falls among elderly is due to a high risk of falling caused by impaired mobility, sight and balance in combination with increased vulnerability as a result of fragile bones as well as comorbid conditions. Researchers at the department of Neuronics at KTH has developed a shock-absorbing floor that aim to reduce the risk of fall related fractures. The floors has shown promising results in mechanical drop tests but requires further analysis before it can be implemented in retirement homes. The goal of this master thesis is to refine, adapt and validate the finite element model THUMS 4.02 for fall simulations. The model will then be used to analyze the shock absorbing ability of various floor systems. Model adaptations included modification of the material properties of the adipose tissue and cartilage in the hips and implantation of tied internal contacts. Validation was performed against data from two experimental studies selected in a literature study, dynamic impact with isolated pelvis and lateral hip impact of complete PMHS. The experimental setups were reproduced in LS-Dyna and relatively close agreement for the force curves could be displayed in both cases. The model also showed realistic force response for fall simulations and a force reduction with up to 23% in simulation to the KTH developed floor system, differences could be seen for different fall positions of the model. Fall simulations agreed well with clinically and scientifically documented fracture loads and patterns. Further studies needs to be performed to further validate the model and analyze effect of different geometrical properties of floor system.

This study investigated the architecture and composition of eight lower limb musclesin typically developing children using diffusion tensor imaging and mDixontechniques, respectively. Moreover, the correlation between intramuscular fat fractionand force generation capacity was studied. It was observed that intramuscularfat fraction differed in the considered muscles. A positive correlation was observedbetween the maximum voluntary contraction and the intramuscular fat fraction ofgastrocnemius, soleus and tibialis anterior in four subjects, implying that maximumvoluntary contraction increases proportionally with intramuscular fat fraction.This outcome disproves the primary hypothesis which states that lower intramuscularfat fraction corresponds to a higher amount of produced force. It wasconcluded that intramuscular fat fractions do not affect force generation capacityin typically developing children.

As heart disease is the leading cause of death worldwide it is of great interest to improve our understanding and treatment of different heart conditions. One step in doing this might be developing computational models of how the blood flows in the heart. This paper builds upon prior models by Larsson et al. (2017) and Svelander et al. (2019) for simulating the blood flow in the left ventricle using patient-specific data, to model the effects of an insertion of a so called MitraClip™ into the mitral valve. The simulations are carried out by numerically solving the Navier Stokes equations using computational fluid dynamics. The simulation results show that an insertion of a MitraClip™ significantly increases the inflow velocity of the blood into the left ventricle and increases the pressure and vorticity at the bottom of the ventricle, as well as the shear stress on the endocardial wall. Furthermore, it is shown that the effects on the blood flow depend on the distance from the center of the MitraClip™ to the center of the mitral valve, and also on which side of the center the clip is set. These results underline the importance for the model to be patient specific, and indicate a potential usage. A physician could use the model to assess the heart condition of a patient and evaluate how different treatments, like MitraClip™ therapy, would impact that specific patient. By developing the described model it might become a tool for physicians in the future.

The mechanical properties of liver tissue such as stiffness are closely correlated with various diseases. Magnetic resonance elastography (MRE) aims at estimating these mechanical properties by imaging the waves induced by an external driver in the liver. Due to its promising ability to non-invasively diagnose and monitor the progression of disease, different methods to reduce technical limitations has been developed over the last years. This includes the use of newer MRE sequences, the capability of 3D MRE and different techniques of generating mechanical excitation in the liver tissue. Since there are different acquisition methods available it is of importance, from both a clinical as well as a research perspective, to have a reliable way of assuring the quality of the measurements. Therefore, this project investigates the image quality as well as the reproducibility of the mechanical properties for different systems and settings. This was done by analyzing 3D MRE measurements of 155 patients and 19 healthy volunteers from research studies at The University Hospital of Linköping. Additional data were collected to further evaluate reproducibility. These were taken on the same volunteer using different hardware, wave amplitudes and pulse sequences at 1.5 and 3 T. The different acquisition methods were shown to produce comparable measurements of the mechanical properties of the liver. However, further investigation would be of interest, namely due to a discrepancy between a clinical system with a 2D-GRE sequence and the corresponding research systems. It was also found that the values of the mechanical properties all increase with frequency with the exception for the attenuation of the waves. Furthermore, by using quality parameters in the software KIR, a method for determining when measurements using 3D MRE does not have sufficient image quality was implemented. This work paves the way for further development of methods to ensure the quality when assessing the extent of diffuse liver disease.

Reverse Total Shoulder Arthroplasty (rTSA) is an increasingly common approach to treating different shoulder injuries. The rTSA results in increased force from m. deltoideus which originates from acromion. However, postoperative fractures on the scapula have occurred in some cases. These fractures are divided into 3 different types depending on where the fracture occurs. There is no recommended treatment for type 3 fractures. This project is a product development project with the purpose to find a solution to the fixation problem of type 3 fractures.To reach the project goal, the group has used well-known and proven product development methods, calculations, FEM analyzes and a model assembly analysis. The concept development was performed by interviewing orthopedics who have a lot of experience with rTSA and osteosynthesis related to these fractures. A prototype, which shows the features of the fixation plate, was made using 3D printers.The result of this project has provided a fixation plate that meets the groups requirements and has features that a modern fixation plate has today. In addition, two types of extra plates mounted on the fixation plate to the thin structure of spina scapula, was developed to counteract the axial force. The fixation plate shows excellent results on the FEM analyzes and assembly analysis performed on a scapula model. The prototype has also been given good testimonials from the orthopedics who participated in the project.