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  • 51.
    Granholm, Hanna
    KTH, School of Technology and Health (STH).
    Patients' Participation in Decisions in an Anaesthesia Healthcare Setting: A survey of patients' and personnel's attitudes and experiences2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A need for the personnel at the Anaesthesiology and Intensive Care Unit at Danderyd Hospital to better understand their patients’ experiences and attitudes towards participation in their care was identified by the Clinical Innovation Fellowship program at Centre for Technology in Medicine and Health. This study aimed to provide the Anaesthesiology and Intensive Care Unit with information on patients and personnel’s experiences and attitudes towards patients’ participation; this would allow them to understand how they should focus their resources. A crosssectional and group comparing survey was performed at the Anaesthesiology and Intensive Care Unit in the spring of 2016. A total of 55 patients scheduled for surgery and 38 from the personnel at the Anaesthesiology and Intensive Care Unit participated. The results show there is high overall satisfaction among the participants of their experiences of patients’ participation. The majority of the patients wanted to be passive in decisions, no connections between personal characteristics and preferred level of participation was found. Patients who did not felt they had been able to participate enough also felt uninformed. Furthermore, physicians seemed to have better opportunities to include patients in decisions compared to the nurses. The healthcare systems should work to adapt the care for each individual patient and to provide them with information suitable for the individual in order to support patients’ participation; IT-systems could be one way of doing this. Future studies should further investigate which factors could influence patients’ participation and how healthcare services and technology could be designed in order to support patient participation.

  • 52.
    Grishenkov, Dmitry
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Ultrasound. KTH, School of Technology and Health (STH), Medical Engineering.
    Diagnostic Power of Different Tissue Doppler Parameters during Ultrasound Cardio-Vascular Investigation2007Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The department of Medical Technology, where I have done Master thesis project, develops and researches new method and technique within areas where ultrasound can be used to obtain the image of anatomical structure, functional capabilities and to suggest required treatment.

    Nowadays cardio-vascular diseases, such as infarct, atherosclerosis and ischemic syndrome, are one of the most widespread diseases in the world that’s why timely detection, identification and treatment are so important.

    The Master of Science qualification report consists 3 major parts: Medico-biological part, Design and Research parts.

    In Medico-biological part has been analyzed anatomical and physiological structure of the heart, current status of echocardiography with comparing with other techniques, summary of ultrasound methods with list of parameters that can be achieved is presented.

    In Design part has been developed new graphical modality based on Delta-V pump model using vector based statistical analysis for identification patients with ischemia. Software algorithm for automatically determine characteristic points for state diagram written in MatLab has been developed and implemented.

    In Research part in the first task using commercially available software based on Principal Component Analysis collected data from the hospital patients has been studied, results proved hypothesis concerning time variables importance; in the second task graphical module has been examined using collected data from the hospital patients both normal and with different cardio-vascular disease, and the results show good detection power of the algorithm.

    At the end of the project presentation has been done and report has been published.

    This project has been done in collaboration with the biggest medical institute in Sweden – Karolinska Institute - and results will be used in medical practice in Karolinska University Hospital in Huddinge and for future scientific needs.

     

  • 53.
    Gunnlaugsdottir, Helga
    KTH, School of Technology and Health (STH).
    Spectroscopic determination of pH in an arterial line from a Heart-lung machine2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    There is a need for a real-time, non-invasive method to monitor blood pH in a patient line during cardiopulmonary bypass, as today’s methods are both invasive and time consuming. Blood pH is an indicator of physiological and biochemical activity in the body and needs to be kept within a relatively narrow range, typically between 7.35-7.45. A pH value outside this range can be critical for the patient and therefore needs to be carefully monitored throughout the course of cardiopulmonary bypass. In this study the feasibility of using spectroscopic methods for indirect measurement of pH was investigated, and both transmission and reflectance spectroscopy were tested. The results showed that NIR reflectance spectroscopy is a feasible technique for blood pH monitoring during cardiopulmonary bypass. A strong correlation was found between measured pH values and spectral output in the wavelength range 800-930 nm. It was suggested that by means of the statistical partial least square regression method, a model could be created with three regression factors with a cross-validated R2 of 0.906 and a prediction error RMSEP of 0.089 pH units. The results presented here form a foundation for further analysis and experiments with larger sample set and more controlled experimental environment. 

  • 54.
    Hagman, Anna
    KTH, School of Technology and Health (STH).
    The Knowledge- and Adoption Level of Standards for Technical Interoperability among Providers of Healthcare Information Systems2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis was one of the deliverables of StandIN. The purpose of StandIN was to propose a common framework including standards for technical interoperability. The goal of this thesis was to structure and analyze information about the knowledge- and adoption level of the standards among providers of healthcare information systems (HIS's). Moreover, it aimed to evaluate different aspect that might affect the adoption.

    The target group was providers of HIS's used in Swedish county councils and regions. The information was gathered through a survey and semi-structured interviews, and stored in an Excel database. From the database, Pivot tables and charts were created in order to show the knowledge- as well as adoption level of the different standards. The results were thereafter compared to theory about interoperability and standard adoption.

    It was clear that the knowledge level varied for the different standards. In addition, the adoption level was very low - except from CCOW and HL7 v2. Least adopted were domain-specific standards. The results also indicated a trend for only adopting parts of standards. Moreover, many providers stated that they performed specific integrations rather than followed common standards. This seemed to be due to the choice of standards being too wide, and the actual adoption not being consistent among the different providers. According to the providers, an introduction of a national framework based on uniform and consistent international standards was an awaited solution to the problem.

    A future extension of this thesis would be to perform a similar study involving the customers. The database could also be used to do clustered analyses of the adoption state in different county councils and regions. Moreover, it could be used to analyze the development of standard adoption over time.

  • 55.
    Hailu, Abebe
    et al.
    KTH, School of Technology and Health (STH).
    Lundqvist, Fredrik
    KTH, School of Technology and Health (STH).
    Prototype Development of an A-Mode Ultrasound Based Intrafraction Motion Management System2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Owing to the steep dose fall-off curves of high precision and accuracy radiation therapy (RT) modalities such as stereotactic body RT (SBRT), treatment plans with extraordinarily small margins to organs at risk (OARs), such as the spinal cord, has been made possible. With this development, patient movements during treatment, i.e. intrafraction motion (IFM), must be monitored more closely. This master thesis was aimed at developing an A-mode ultrasound prototype to detect the motions of the cervical spine as part of an IFM management (IFMM) system. Current IFMM systems have several drawbacks, including invasiveness and indirect measurements.

    The existing prototype was tested in order to identify areas of improvement. The prototype developed was equipped with a preconditioning circuit that retains the frequency information of the signal. Furthermore, software was developed based on wavelet filtering and enveloping using the Hilbert transform. Multiple logic algorithms were added in order to handle lost signals, competing echoes, echoes from soft tissues etc.

    The newly-developed prototype was found to have higher accuracy and precision than the pre-existing prototype. It was also more robust when measuring distance to the spine. A difficulty in segmenting the echo for bone arises for low quality signals. Therefore a compromise exists between setup time, including probe adjustment, and signal quality. Future work includes the manufacturing of a new neck rest to enable robust probe adjustment and fixation.

  • 56.
    Hansen, Lisa
    KTH, School of Technology and Health (STH).
    Evolution of a galvanotaxis chamber and an introductory study of the important parameters2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 57.
    Hendrikse, Natalie
    KTH, School of Technology and Health (STH).
    Development of a Novel Selection Method for Protease Engineering: A high-throughput fluorescent reporter-based method for characterization and selection of proteases2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Proteases are crucial to many biological processes and have become an important field of biomedical and biotechnological research. Engineering of proteases towards therapeutic applications has been limited due to the lack of high-throughput methods for characterization and selection. We have developed a novel high-throughput method for quantitative assessment of proteolytic activity in the cytoplasm of Escherichia coli bacterial cells. The method is based on coexpression of a protease of interest and a reporter complex consisting of an aggregation-prone protein fused to a fluorescent reporter. Cleavage of a substrate sequence situated between the two reporter complex proteins results in increased whole-cell fluorescence proportional to proteolytic activity, which can be monitored using flow cytometry. We have demonstrated that the method can distinguish efficiencies with which Tobacco Etch Virus (TEV) protease processes different substrates. We believe that this is the first method in the field of protease engineering that enables simultaneous measurement of proteolytic activity and protease expression levels and can therefore be applied for substrate profiling, as well as screening and selection of libraries of engineered proteases.

  • 58.
    Hubert, Alexis
    KTH, School of Technology and Health (STH). Elekta AB.
    Spectroscopic Study of Radiation around the Leksell Gamma Knife for Room Shielding Applications2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Any center planning to install a Gamma Knife radiosurgery unit has to provide for an efficient shielding of the treatment room, to protect the patient, the staff and the public, against undesired radiation. The shielding barrier design is controlled by national and international recommendations; the reference documents for gamma ray radiotherapy facilities are the National Council on Radiation Protection and Measurements (NCRP) reports 49 and 151. However, some facts highlighted in this thesis point out that NCRP methods are ill-adapted to the Gamma Knife. Spectroscopic measurements were performed around the Gamma Knife with a Germanium detector. They revealed that the radiation field contains few high energy photons, is highly anisotropic, and that the leakage level is much lower than the NCRP estimation. These observations led to the development of a new approach to determine the necessary shielding, based on the actual and directly measurable radiation field around the unit. This method would reduce the shielding oversizing induced by the unsuitability of the NCRP recommendations for the Gamma Knife.

  • 59.
    Hussain, Shabbir
    KTH, School of Technology and Health (STH).
    A Simple PET Imaging Educational Demonstrator2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Recent interests in computer based tools and simulations for PET imaging studies have been a leading source for many new developments. A strong emphasis in these studies has been to improve and optimize the PET scanners for better image quality and quantification of related system parameters. In this project, an attempt has been made to develop a Matlab tool intended to be of educational nature for new students where one can perform demonstration of PET-like imaging in a simple and quick way. This demonstration tool utilizes a high resolution, voxel based digital brain (Zubal) phantom as a primary study object. A tumor of specific size is defined by the user on a chosen slice of the phantom. The output images from this tool show the exact location of the predefined tumor. The algorithm attempts to estimate the positron emission direction, positron range distribution and photon detection in a circular geometry. Additional attempt has been made to estimate certain statistical parameters against a specific amount of radiotracer uptake. These include spatial resolution, photons count, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the ultimate PET image. Dependence of these estimated results by the tool on different system input parameters has been studied.

  • 60.
    Hákonardóttir, Stefanía
    KTH, School of Technology and Health (STH).
    Prosthetic Control using Implanted Electrode Signals2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report presents the design and manufacturing process of a bionic signal messagebroker (BSMB), intended to allow communication between implanted electrodes andprosthetic legs designed by Ossur. The BSMB processes and analyses the data intorelevant information to control the bionic device. The intention is to carry out eventdetection in the BSMB, where events in the muscle signal are matched to the events ofthe gait cycle (toe-o, stance, swing).The whole system is designed to detect muscle contraction via sensors implantedin residual muscles and transmit the signals wireless to a control unit that activatesassociated functions of a prosthetic leg. Two users, one transtibial and one transfemoral,underwent surgery in order to get electrodes implantable into their residual leg muscles.They are among the rst users in the world to get this kind of implanted sensors.A prototype of the BSMB was manufactured. The process took more time thanexpected, mainly due to the fact that it was decided to use a ball grid array (BGA)microprocessor in order to save space. That meant more complicated routing and higherstandards for the manufacturing of the board. The results of the event detection indicatethat the data from the implanted electrodes can be used in order to get sucient controlover prosthetic legs. These are positive ndings for users of prosthetic legs and shouldincrease their security and quality of life.It is important to keep in mind when the results of this report are evaluated that allthe testing carried out were only done on one user each.

  • 61.
    Illerstam, Fredrik
    KTH, School of Technology and Health (STH).
    Quality Assurance of the Spatial Accuracy of Large Field of View Magnetic Resonance Imaging2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In todays Radiotherapy Treatment Planning, RTP, it is common to use Computed Tomography, CT, together with Magnetic Resonance Imaging, MRI, where CT provides electron density information and a geometrical reference, and where MRI provides superior soft tissue contrast. To sim- plify the workflow and improve treatment accuracy, research groups have demonstrated how to exclude CT and use a MRI-only approach. In this thesis, a method for spatial distortion analysis, ultimately enabling quality assurance, QA, of the spatial accuracy of MRI, was defined, tested and evaluated.

    A phantom was built to cover the entire clinical Field Of View, FOV, and 6mm-diameter fluid filled paintball markers were placed in a well-defined geometrical pattern within the phantom, and used as positive contrast. The phantom was imaged with a 3D Fast Gradient Echo sequence and a 3D Fast Spin Echo sequence. The markers were identified in the image data by a MATLAB-algorithm, and the location of the center of mass was calculated for each marker and compared to a theoretical reference. The location error was defined as the spatial distortion - a measurement of the spatial accuracy. Imaging parameters were altered and the effect on the spatial accuracy was analyzed.

    The spatial distortions were successfully measured within the entire (maximal) clinical FOV. It was shown that high readout bandwidth reduced distortions in the frequency encoding direction. These distortions could thus be attributed to B0-inhomogeneities. It was also determined that increasing the readout bandwidth to the maximum value reduced the maximum distortions in the frequency encoding direction to the same level as the maximum distortions in the other two phase-encoding directions of the 3D acquisitions. The voxel size had a very small effect on the spatial accuracy, enabling large voxelsize to be used when imaging the phantom, to decrease the scan time.

    The method was deemed capable of serving as a basis for QA of the spatial accuracy of large FOV MRI, which is needed in future MRI-only RTP approaches. 

  • 62.
    Iveroth, Solveig
    KTH, School of Technology and Health (STH).
    Framtagning av personas för analys av Reumatologiska klinikens (Karolinska Universitetssjukhuset) patientunderlag2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Abstract

    Personas are fictional users which are defined by their goals, and are often used to represent a specific group of people. The purpose of this study consisted of creating personas in order to analyze the patients of the Karolinska University hospital´s Rheumatology clinic. This study’s aim was to create a more patient-centered healthcare, and to give focus to the patients’ goals and needs. The assignment is an inquiry from CTMH, and is performed in collaboration with Karolinska University hospital and Clinical Innovation Fellowships.

                          The process started with a literature study, followed by developing and submitting an application for ethical vetting. The next step was to interview some of the personnel of Karolinska University hospital that had experience with patients suffering from a rheumatic disease. This was done in order to get a background before the next phase of the project took place: interviewing patients. The scope of the study was limited to only including patients suffering from the rheumatic disease Rheumatoid arthritis (RA). Based on the interviews done with patients, a survey was created and sent out to 200 randomly selected patients with RA. The result of the survey was then used in several cluster analyzes, which divided the patients into groups based on their answers. The groups from these analyzes that gave the clearest division and the most interesting answers were then selected.

                          The results consisted of four personas which were evaluated by a focus group. The conclusion of the results and the evaluation was that the personas created are easy to recognize and well usable. The four personas are a good tool for analyzing the patients of the Rheumatology clinic, and are a step towards placing the patients’ goals and needs as key elements in the healthcare of today.

  • 63.
    Jahnsen, Ann-Lena
    KTH, School of Technology and Health (STH).
    Development of a quantum dot based strategy for Gram-specific bacteria differentiation2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Abstract

    Time-consuming diagnosis of bacterial blood stream infections and inappropriate antibiotic therapy have critical implications for patient outcome – with mortality figures rising for every hour of delayed treatment. The development of diagnostic methods that are capable of selective and rapid bacteria detection, and do not rely on preliminary blood culturing and Gram-staining procedures, is imperative in providing effective therapy and preventing multi-resistance. The aim of this dissertation was to develop a quantum dot based and Gram-specific bacteria labelling protocol. Focused on the detection of Gram-negative species, a two-step conjugation protocol was produced to functionalise quantum dots with anti-lipid A antibodies. Ionic adsorption and EDC chemistry were used to obtain oriented and covalent conjugation of antibodies to the quantum dot surface. In order to reduce non-specific binding of unreacted carboxylic groups on the conjugates to the bacterial membrane, and optimise the accuracy of detection, blocking experiments were conducted with molecules that could provide a neutral surface charge and sterically block open sites. To access lipid A on E. coli cells, three different antigen retrieval methods were tested.

    As a result, the developed quantum dot-anti lipid A conjugates were able to detect and specifically label Gram-negative E. coli cells after treatment with 0.6mM EDTA or acetic acid pH 3.58 at 42.5°C. 1% BSA reduced non-specific binding to untreated E. coli cells. Furthermore, in comparison to experiments performed with Tris as a blocking agent, the protein reduced non-specific binding to Gram-positive cells. The results obtained in this project are a step further in the development of a new method to rapidly detect bacteria Gram-specifically.

  • 64.
    Janjic, Jovana
    KTH, School of Technology and Health (STH).
    Design of an In-vitro Set-up for Sonothrombolysis of human blood clots using microbubbles2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Several studies suggest that the use of ultrasound in conjunction with microbubbles (MBs) can induce the lysis of the blood clots through acoustic cavitation and through the production of microjets and microstreaming. However, there is no accordance about the optimal ultrasound parameters that have to be considered in order to achieve the maximum thrombolytic effect, neither a clear agreement about the type of MBs that have to be used.

    This project had two main goals: the design and optimization of an in-vitro set-up for the study of clot lysis within coronary arteries and its testing with ultrasound in conjunction with two different types of MBs. The MBs considered were the 3MiCRON MBs and the SonoVue MBs.

    The ultrasound sequence was developed using a programmable ultrasound architecture (Verasonics, Inc) and was tested using commercially available clinical transducers.

    Using the designed set-up and varying the ultrasound parameters (frequency, pulse length and pulse amplitude) it was possible to study the clot lysis effciency in conjunction with the two types of MBs. For the 3MiCRON MBs no increase in clot lysis was found with the implemented ultrasound parameters, while considering the SonoVue MBs, a 10% increase in clot lysis was found with 10ms long pulse delivered at 50V (peak-to peak value).

    The obtained set-up had several aspects in common with the real situation of occluded coronary arteries, although some limitations were present and further optimizations are required.

    Further work is required in order to assess if different combination of ultrasound parameters are able to lead to an increase in clot lysis when delivered with 3MiCRON or SonoVue MBs.

  • 65.
    Jansson, Magnus
    KTH, School of Technology and Health (STH), Medical Engineering.
    A 3D-ultrasound guidance device for central venous catheter placement using augmented reality2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Central venous catheterization (CVC) is performed frequently in clinical practices in Operation Rooms(OR) and Emergency Rooms(ER). CVC is performed for different reasons such as supply nutrition or medicine. For CVC ultrasound (US), diagnostic device is preferable among other medical imaging technologies. Central Venous Catheterization (CVC) under the 2D US guidance requires skills for catheter placement to avoid damaging non-targeted blood vessels. Therefore, there is a great need for improvements in the CVC field where mechanical complication has a risk of occurring during the procedure, for example misplacement of the needle.

    This master thesis project was performed at Kyushu University department of mechanical engineering and collaboration with Maidashi Kyushu University Hospital department of Advanced Medicine and Innovative Technology in Japan. This thesis is aimed to develop a new simple and cheap guidance system for CVC placement. The system performed on a Tablet PC and will be using already existing Ultrasound machines in Hospitals and Augmented Reality(AR).

    The project developed a simple AR-System for CVC placement with use of the ArUco library. The new developed system takes information from Ultrasound images and constructs a 3D-model of a vein and artery. Then the 3D-model is augmented on the patient through the tablet PC by using the ArUco library. The construction and augmentation is all performed on the tablet PC and has a small computation to complete the necessary procedures for the 3D-blood vessels.

    The AR-system has a simple control where the interface of the system is a simple push and action system. When a good visualization of the blood vessels and Doppler effect is shown on the ultrasound machine, the surgeon presses the screen and the image is saved. After about five images are acquired, the system builds the 3D-model and augments it on the patient using a marker.

    For the development of this system it implemented the waterfall method where each step was tested and checked, before moving to the next step.

    A full functional system was developed and tested. From the tests performed it is shown that there were limitations due to segmentation and depth perception. But the system has possibilities as an aid for CVC placement.

  • 66.
    Javanshir Moghaddam, Mandana
    KTH, School of Technology and Health (STH), Medical Engineering.
    Coupled Curves Segmentation2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis, we proposed distance enforced penalized (DEeP) random walks segmentation framework to delineate coupled boundaries by modifying classical random walks formulations. We take into account curves inter-dependencies and incorporate associated distances into weight function of conventional random walker. This effectively leverages segmentation of weaker boundaries guided by stronger counterparts, which is the main advantage over classical random walks techniques where the weight function is only dependent on intensity differences between connected pixels, resulting in unfavorable outcomes in the context of poor contrasted images. First, we applied our developed algorithm on synthetic data and then on cardiac magnetic resonance (MR) images for detection of myocardium borders. We obtained encouraging results and observed that proposed algorithm prevents epicardial border to leak into right ventricle or cross back into endocardial border that often observe when conventional random walker is used. We applied our method on forty cardiac MR images and quantified the results with corresponding manual traced borders as ground truths. We found the Dice coefficients 70%   14% and 43% ±14% respectively for distance penalized random walks and conventional one.

  • 67.
    Jernberg, Cassandra
    KTH, School of Technology and Health (STH).
    A Computational Model for Fracture Healing Integrated with Mechanical Stimulation and Growth Factors2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Non-union bone fractures are a standing problem for clinical treatments. It has been found that the exogenous growth factor recombinant human bone morphogenetic protein-2 (rhBMP-2) induces bone healing in potential non-union fractures. However, the currently used clinical dose of rhBMP-2 is high and causes side-effects. Mechanical loading is known to enhance the induced effects of rhBMP-2 in bone healing, which may lead to a reduced required dose. Yet, the exact underlying mechanism is unknown.

    To further investigate the combined role of mechanical loading and rhBMP-2 in the early phase of fracture healing a 2D computational model was developed. The model uses a lattice-based approach where biological rule-based events are combined with finite element analysis to simulate both untreated bone healing progression and when subjected to mechanical loading and rhBMP-2. Two healing cases were investigated:  normal fracture healing in a small bone defect (1 mm gap) and non-union fracture healing in a large bone defect (5 mm gap). By varying the magnitude and timing of applied load as well as the rhBMP-2 dose, a combination that would reduce the currently used rhBMP-2 dose and still enable healing in a large bone defect was searched.

    The model could simulate fracture healing in a large bone defect when subjected to rhBMP-2, independently of the applied load. Also the expected non-union result in a large bone defect without applied rhBMP-2 was obtained. The model could not capture normal fracture healing in a small bone defect as well as bone remodelling.

    It was found that a 50 % reduced rhBMP-2 dose could not induce healing in a large bone defect when applied separately but when applied together with load. Additionally, this combination of stimulation gave similar results compared to other combinations using higher rhBMP-2 doses.

    To conclude, even though the model was able to replicate some of the healing events seen experimentally, it is in need of modifications to correct current deficiencies. Still, after some further development and validation, the model has the potential to be used in future studies of fracture healing when influenced by mechanical loading and rhBMP-2. The found possibility for a reduced dosage of rhBMP-2 when applied together with load has to be further investigated before any conclusions can be drawn.

  • 68.
    Jurcova, Martina
    KTH, School of Technology and Health (STH). Phelma Grenoble INP.
    Validation of simulation tool for C-arm X-ray systems: Source and scatter model2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Continuous improvement of image quality is one of the priorities in medical imaging. Therefore, development of a simulation tool allowing to generate realistic images would be of great value to understand better the impact of the components on the image quality metrics and to choose imaging set-ups or new design features to optimize output of existing systems and to prototype new ones and to formalize the link between objective and subjective image quality metrics.

    Therefore, the purpose of this project, was to contribute to adaptation and validation of an existing simulator for simulation of C-arm X-ray imaging.

    Firstly, the study of the existing simulation tool was performed to choose further development axes.

    Afterwards, preliminary estimations of simulation complexity by evaluating the number of photons for a given imaging examination were performed.

    Previous studies[1] showed the determining impact of focal spot on imaging performance (reducing the limiting spatial frequency in common examination conditions) of X-ray interventional imaging systems.  Therefore, the work focused on the improvements of source model, in particular realistic focal spot was defined and simulations of images with close-to-real sharpness were performed and compared to experimentally acquired images.

    Finally, a part of this project was dedicated to scatter study. An experimental set-up and "scatter map" analysis were designed to determine the scatter evolution as function of imaging field-of-view.  First simulations were also performed.

    [1] Samei, E., Ranger, N., MacKenzie, A., Honey, I., Dobbins, J. and Ravin, C. (2008). Detector or System? Extending the Concept of Detective Quantum Efficiency to Characterize the Performance of Digital Radiographic Imaging Systems 1. Radiology, 249(3), pp.926-937.

  • 69.
    Jönsson, Maria
    et al.
    KTH, School of Technology and Health (STH).
    Boije, Malin
    KTH, School of Technology and Health (STH).
    Biomechanical Simulations of a Flywheel Exercise Device in Microgravity2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Bone loss and muscle atrophy are two main physiological conditions affecting astronauts while being in space. In order to counteract the effects, at least two hours of aerobic and resistant countermeasure exercise is scheduled into their working day, seven days a week. Yoyo Technology AB has developed a resistance exercise device based on the flywheel principle, providing a load independent of gravity. However, there is no biomechanical research done on the efficiency of the device in microgravity, from a human movement point of view using simulation software.

    The aim of this thesis was to evaluate the effects of performing a leg press on the flywheel exercise device in a microgravity environment. Simulations of performing a flywheel leg press in earth gravity, microgravity and performing a conventional squat were done. The evaluated parameters were reaction forces, joint angles, joint moments, joint powers and muscle recruitment in the lower extremities. The simulations were done using a biomechanical simulation software based on a motion capture data collection.

    From the results two conclusions were proposed. Performing a flywheel leg press in microgravity environment or on earth provides at least as much peak moment as a body weighted squat performed on earth. Furthermore, performing a flywheel leg press in microgravity will induce a higher activity level among hip extensors and knee flexors compared to performing a flywheel leg press on earth. 

  • 70.
    Karlsson, Frans
    et al.
    KTH, School of Technology and Health (STH).
    Kalmaru, Edvin
    KTH, School of Technology and Health (STH).
    Optimizing an Ultrasound Based Tissue Micro Engineering System: Optimering av ett Ultraljudsbaserat Cellmanipuleringssystem2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    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. 

  • 71.
    Karlström, Marina
    KTH, School of Technology and Health (STH).
    Självmonitorering som väg till ökat patientdeltagande2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Telemonitorering är teknik för att medicinskt övervaka individer på distans. Tekniken har, trots att den är ny och outforskad, stora förväntningar på sig att vara en del av lösningen på vårdens framtida utmaningar. Syftet med den här rapporten är att presentera en översiktlig analys av telemonitorering som den används i vården idag. Dessutom att diskutera vilka vårdprocesser den bäst ska tillämpas i för att framöver leda till så stor patientnytta som möjligt.

     

    Området är svåröverblickbart av flera anledningar. Bland annat på grund av brist på en gemensam terminologi som används konsekvent och att den empiri som hittills genererats för att undersöka nyttan har gett spridda resultat. Mot den bakgrunden valdes en kvalitativ metod som har bestått i att genomföra litteraturstudier, omvärldsbevakning, intervjuer samt en avgränsad fördjupning i hur tekniken skulle kunna användas hos en vårdaktör (Health Navigator AB). Analysen av det insamlade materialet har resulterat i insikten att det största potentiella resultatet av tekniken följer av att den kan leda till ökat vårddeltagande. Därför har benämningen ”självmonitorering” valts.

     

    Rapportens resultat är en nulägesbeskrivning som omfattar områdets största intressenter, tongivande studier, projekt samt identifierade möjligheter och utmaningar. Slutsatsen är att det både finns ett behov av, och vinster med, självmonitorering – förutsatt att den utformas efter ett antal framgångsfaktorer som presenteras i rapporten.

  • 72.
    Katrínardóttir, Hildigunnur
    KTH, School of Technology and Health (STH), Medical Engineering.
    Finite Element Modeling of Chest Compressions in CPR2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Factors affecting the risk of ribcage injury in adult subjects during CPR were investigated using the torso region of the THUMS model, a full human body FE-model, representing an average adult male. The thoracic dynamic response of the model was compared to experimental PMHS hub loading impact data and live-subject CPR data found in the literature. The model was then used to study the risk of obtaining injuries in various simulated CPR conditions, also varying the stiffness of the costal cartilage.

    Parameters that are known to predict induced injuries were extracted from the model simulations, i.e. chest deflections, and maximum 1st principal strain and von-Mises stress in the ribs and sternum, as well as the pressure in the heart muscle. These were compared with values that have been reported to have the potential to cause injury. The predictions were compared to experimental findings of the probability of CPR resulting in fractures of the ribs and sternum.

    The previously mentioned parameters did not reach high enough values to predict fracture occurrences, but interesting trends were highlighted with regards to the different loading conditions investigated. It was demonstrated that human body FE-model simulation studies can be useful for investigating the influence of different CPR related loading conditions on the risk of occurrences of rib and sternal fractures. 

  • 73.
    KHALID, SYED GHUFRAN
    KTH, School of Technology and Health (STH).
    Quantification of Hyperhidrosis using Electronic Sudometer2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Human skin has various pathologies in the form of acute and chronic diseases. Some are only cosmetic diseases which are not harmful for life but they can affect mental health and disrupt daily activities. Hyperhidrosis is one of these cosmetic diseases which may be caused by diabetes, infections, or thyroid hyper activity, or can be inherited. There are some examinations for testing hyperhidrosis, e.g. gravimetric and minor starch-iodine test. There are some devices that can measure sweat but are not specifically used or even intended for use on hyperhidrosis.

    A non-invasive prototype instrument called Electronic Sudometer using the principle of electrical impedance measurement has been developed. The philosophy behind this prototype is to make an instrument which can detect hyperhidrosis during homeostasis as well as in pathological condition. The device injects a sinusoid electric current and detects the ensuing voltage, which is proportional to the impedance of sweat on top of the skin during hyperhidrosis. For this prototype, the electrode system is made of brass rings mounted on a handle. The signal is then processed in electronic assembly. Processed output is transferred to a Laptop with specially made connecting wire. Computer having Sound Card Oscilloscope (Lab View based software) plots the signal and shows voltage level corresponding to sudor level. The signal output can also be displayed on a SmartPhone having software called Osciprime, requiring another specially made interface.

    Laboratory test results in the form of a plot of output voltage vs. impedance show accuracy of the device. The impedance results can be translated to sweat level because impedance decreases with increasing sweat during hyperhidrosis. The Sudometer was also calibrated using fixed precision resistors over its working range. Laboratory tests were carried out using an artificial skin at various sweat levels and to a yeast tissue model. Hydration of the artificial skin was quantified by weighing precision cut samples on a laboratory balance. Results from two test persons (the author and a student friend) are also included in this Master Thesis. During these experiments, the laptop computer and SmartPhone, respectively, were on internal battery to eliminate electric hazard.

    Any clinical device must be validated for accuracy and evaluated for safety before applying it on patients – the latter has not been done with the prototype. The author is aware of potential electrical risks, and thus the whole system was disconnected from mains 230V during measurements on himself and a student friend. The device output seems to be well correlated to sweat level although electrolytes were not taken into account. Being a palmar hyperhidrosis patient himself, the author applied the Electronic Sudometer on his palms and the results look quite promising. At different environmental temperatures, the author checked elicited sweat responses. Patient safety is always a concern for clinicians regarding new devices. For this reason, the device itself has been made battery operated, and a new version will be entirely powered from a SmartPhone.

  • 74.
    Khoogar, Sayeh
    KTH, School of Technology and Health (STH).
    Implementation of a New Continuous and Wireless Monitoring System: FROM THEORY TO REALITY2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 75.
    Kilinc, Derya
    et al.
    KTH, School of Technology and Health (STH).
    Ghattas, Mattias
    KTH, School of Technology and Health (STH).
    Implementing an Intelligent Alarm System in Intensive Care Units2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Today’s intensive care units monitor patients through the use of various medical devices, which generate a high ratio of false positive alarms due to a low alarm specificity. The false alarms have resulted in a stressful working environment for healthcare professionals that are getting more desensitized to triggered alarms and causing alarm fatigue. The patient safety is also compromised by having high noise levels in the patient room, which disturbs their sleep. This thesis has developed an intelligent alarm system with an improved alarm management and the use of 23 intelligent algorithms to minimize the number of false positive alarms. The suggested system is capable of improving the alarm situation and increasing the patient safety in critical care. The algorithms were modeled with fuzzy logics consisting of delays and multi parameter validation. The results were iteratively developed by having focus groups with various experts.

  • 76.
    Kraft, Sandra
    KTH, School of Technology and Health (STH).
    Routine Development for Artefact Correction and Information Extraction from Diffusion Weighted Echo Planar Images of Rats2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Biologists and physicians study complex biologic phenomena in which they use advanced imaging methods. They acquire images containing a lot of information which must be extracted in a correct way. This requires computer skills and knowledge in image processing methods which they seldom have. To overcome the problem, this master thesis aimed to develop a routine for artefact correction and information extraction from images acquired in a research project at the Karolinska Institutet in Stockholm. By developing the routine, the thesis showed how software developed for images of human can be applied to images of rats. The routine handles formatting issues and artefact corrections, calculates diffusion metrics, and performs statistical tests on spatially aligned magnetic resonance images of rats acquired with diffusion weighted echo planar imaging. The routine was verified by analysing the images that it had processed and was considered to create reliable images. Future studies within the field should focus on developing atlases of rats and continue the work with identifying how software developed for images of human can be applied to images of rats. 

  • 77.
    Kuutmann, Hanna
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Rosén, Emelie
    KTH, School of Technology and Health (STH), Medical Engineering.
    Smartphone Capnography: Evaluation of the concept and the associated CO2 indicating sensor2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Smartphone capnography is a new concept for respiratory monitoring using a colorimetric sensor in combination with a smartphone and an Android application. Compared to using an infrared spectrophotometric carbon dioxide analyzer (IR-analyzer), the gold standard for respiratory carbon dioxide monitoring, smartphone capnography offers a cheaper and less bulky solution. This master thesis evaluates the performance of smartphone capnography and the colorimetric sensor engineered for this concept. Three different techniques (side stream, shunt stream and main stream) were tested. Additionally, an iPhone application was developed as a proof of concept when using an iPhone for smartphone capnography.

     

    An experimental set-up simulating human breathing was assembled and measurements, at different breathing rates (6-30 breaths/min) and carbon dioxide levels (2-7vol%), were performed with an IR-analyzer as reference. Results showed that capnograms from smartphone capnography was comparable to those from the IR-analyzer and that the approximate accuracy was ±0.25vol% for up to 6 days of use. Results strongly motivate further elaboration of the concept and the three different techniques for measuring.

  • 78.
    Larsson, Anna
    KTH, School of Technology and Health (STH).
    Implementation of Shear Wave Elastography in Cervical Applications2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Each year million of babies are born pre-term, some of these pre-term births occur due to the motherhaving a too soft cervix which can not withstand the forces the baby exposes it to. The aim of thisstudy was to implement and evaluate a programmable shear wave elastography ultrasound system forcervical applications and investigate the optimal settings of shear wave elastography push voltage andshear wave elastography push focus depth. Shear wave elastography is an ultrasound based imagingmodality aiming to evaluate the tissue elasticity by using acoustic radiation forces to induce shear waves.The propagation of the shear waves through the tissue is then tracked in order to calculate the shearwave velocity which is related to the tissue elasticity. B-mode imaging, pushing sequence and planewave imaging have been implemented and measurements have been conducted on four cervical polyvinylalcohol phantoms. The acquired data has been post-processed using Loupas 2D-autocorrector to gainthe axial displacement and enabling tracking of the shear waves to allow evaluation and optimizationof the implemented method. The implemented shear wave technique showed to be able to distinguishcervical phantoms of dierent elasticity and a high pushing voltage and shallow focus push depth havebeen found to produce the most reliable results.

  • 79.
    Lef, Catherine
    et al.
    KTH, School of Technology and Health (STH).
    Dolange, Guillaume
    KTH, School of Technology and Health (STH).
    Understanding Lower Leg Injury in Offset Frontal Crash: A Multivariate Analysis2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Lower leg injury is an important issue in frontal car crash. Although safety in cars has been

    improved by developments such as seat belts and airbags, lower leg injuries have not been

    reduced. These injuries are not life threatening but can result in long term disability and cost a

    lot to society. This study focused on the passenger occupant in offset frontal crashes and aimed

    at understanding and finding ways to reduce the injury criteria for the lower leg: tibia index. A

    finite element model was simplified to introduce parameters which influence on tibia index was

    investigated with a multivariate analysis. The model simplification consisted in removing

    irrelevant parts and replacing other parts by simple foam blocks. More than 1300 simulations

    were run with different parameter values. The results were then analysed by calculating

    correlations and effects of the parameters on tibia index. It was concluded that the presence of

    a knee bolster decreased tibia index. The results also showed a decrease of tibia index when the

    toe pan was angled towards the legs of the passenger. Moreover, a correlation between tibia

    index and the movement of the feet during the crash was found. It was concluded that restrained

    lower legs also presented decreased tibia indices compared to unrestrained ones. Most of the

    results proved to be also valid on the initial, unsimplified finite element model.

  • 80.
    Lillro, Ejla
    KTH, School of Technology and Health (STH).
    Image Sensor System for Detection of Bacteria and Antibiotic Resistance2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Antibiotic resistance is now a recognized problem in global health. In attempts to find solutions to detect bacteria causing antibiotic resistance we turn to technological solutions that are miniaturized, portable and cheap. The current diagnostic procedures cannot provide correct information outside laboratory settings, at the point-of-care, within necessary time. This has led to ineffective treatment of urinary tract infections causing recurrent infections and multi-drug resistant bacteria to spread. The bacteria genes show which antibiotic that is required to eliminate disease and spread of resistance. Hence, the solution would be to perform nucleic acid testing at the point-of-care. By using new DNA amplification methods it is possible to miniaturize the diagnostic test to a so-called Lab-on-a-chip. These solutions would enable sample-in-results-out capability of the system at the point-of-care. For this to work one of the most important factors is fluorescent signal read-out from DNA amplification products.

    In this project the design parameters of such a read-out device was investigated with focus on image sensor sensitivity and device integration. During the project it was found that a low-cost commercial image sensor could be used to record images of a (3.76 x 2.74 mm2) micro well array of nanoliter sized PCR chambers. Different imaging artifacts appearing during sample partitioning were observed, distance dependency between sensor surface well array was investigate, and finally the image sensor function was compared to a fluorescent microscope.

  • 81.
    Lindskog, Klara
    KTH, School of Technology and Health (STH).
    Development and evaluation of a HRV Biofeedback System2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This is a master thesis project written at the School of Technology and Health within KTH, Flemingsberg. It consisted of making improvements in an existing application for tablets used for training HRV biofeedback that was developed as part of an earlier master thesis within the same school. The software involves the user in paced breathing according to an established method.

    The method with HRV biofeedback visualises and trains HRV while the user performs paced breathing. This means that the user maximises the variations of time between heart beats which may have potential to reduce stress and sustain health.

    To improve the software developed earlier at KTH a new graphical user interface was implemented in form of a simple game. In addition further aspects of the program were improved.

    Furthermore, this thesis tried to find evidence for the optimal frequency and duration of HRV biofeedback training for healthy individuals. For this purpose a literature review was performed, showing a lack of evidence for the effectiveness of HRV biofeedback training in healthy individuals. Therefore a study protocol was developed that can be used in future studies aimed at finding the optimal dosage of HRV biofeedback.

  • 82.
    Lundberg, Simon
    KTH, School of Technology and Health (STH).
    Evaluation of a Motion Simulation Platform for Vestibulo-Ocular Research2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The vestibuloocular reflex can be manually elicited by tilting or rotating the head. Manual techniques serve their purpose well and is the golden standard in the clinical work, but they lack control of velocity and movement pattern. However, motion simulation platforms enable automatic control of both velocity and movement pattern.

    One motion simulation platform, named BIRGIT, has been built at the Department of Clinical Neurosciences at Karolinska Institutet but has not yet been in service and require a performance evaluation.

    The objectives with this thesis is to evaluate the accuracy and precision of BIRGIT and evaluate how bodyweight and movement direction impact the performance. The thesis also evaluate whether it is possible to stabilize the head of the patient during the acceleration phase.

    Repeated measurements of acceleration with different loads, desired ac- celeration, direction and motion type (rotational and translational), are per- formed. Dummies are used to simulate bodyweight in the performance study and real persons are used in the head stabilization study. Analysis of variance (ANOVA) is the main statistical tool.

    The results suggest that the platform does not perform equally at dif- ferent load or directions and that there is a bias between desired and true acceleration. The main problems are an inclination of the rails, upon which the chair is mounted, that causes differences between directions and an un- desirable performance characteristic for rotational motions.

    The stabilization study suggest that the head can be stabilized. 

  • 83.
    Lundberg, Simon
    KTH, School of Technology and Health (STH).
    Evaluation of a Motion Simulation Platform for Vestibulo-Ocular Research2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The vestibuloocular reflex can be manually elicited by tilting or rotating the head. Manual techniques serve their purpose well and is the golden standard in the clinical work, but they lack control of velocity and movement pattern. However, motion simulation platforms enable automatic control of both velocity and movement pattern.

    One motion simulation platform, named BIRGIT, has been built at the Department of Clinical Neurosciences at Karolinska Institutet but has not yet been in service and require a performance evaluation.

    The objectives with this thesis is to evaluate the accuracy and precision of BIRGIT and evaluate how bodyweight and movement direction impact the performance. The thesis also evaluate whether it is possible to stabilize the head of the patient during the acceleration phase.

    Repeated measurements of acceleration with different loads, desired ac- celeration, direction and motion type (rotational and translational), are per- formed. Dummies are used to simulate bodyweight in the performance study and real persons are used in the head stabilization study. Analysis of variance (ANOVA) is the main statistical tool.

    The results suggest that the platform does not perform equally at dif- ferent load or directions and that there is a bias between desired and true acceleration. The main problems are an inclination of the rails, upon which the chair is mounted, that causes differences between directions and an un- desirable performance characteristic for rotational motions.

    The stabilization study suggest that the head can be stabilized. 

  • 84.
    Lundbäck, Kristoffer
    et al.
    KTH, School of Technology and Health (STH).
    Dahn, Leonardo
    KTH, School of Technology and Health (STH).
    Preliminary Evaluation of the Clinical Value of an Ultra-Wideband Radar Sensor for Heart Assessment2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Heart dysfunction is a worldly widespread problem that currently is one of the leading causes of death. Studies indicate that many deaths related to cardiac dysfunction could have been prevented if discovered early. Contemporarily, ultrasound and electrocardiography are indispensable modalities for diagnostic purposes and analysis of cardiac function.

    The Ventricorder is an Ultra-Wideband radar sensor manufactured by the Norwegian company Novelda. Ventricorder has been shown to be able detect heart movements and breathing but its actual clinical value remains to be investigated. The Cardiac State Diagram (CSD) is a pre-clinical software tool for visualization of the heart's mechanical function. The CSD is confirmed by pilot studies to be able to constitute a basis for diagnosis and cardiac function assessment. Theoretically, the CSD is well suited to be used with the Ventricorder since the Ventricorder detects small changes over time and information about time events is all that is required for the creation of a CSD.

    Contemporarily, ultrasound tissue velocity imaging (TVI) is usually used for production of CSDs and in this master thesis we examined if the Ventricorder can be used to produce CSDs. This was done by mainly comparing velocity data from the Ventricorder with velocity data from temporally synchronized apical four-chamber images acquired with ultrasound TVI. The results indicate that there is an apparent correlation between these data sets and the Ventricorder should therefore be able to produce data that could constitute the basis for the production of a CSD. What remain now is to confirm these results statistically with a larger test group and to investigate whether all the time instants needed for the production of a CSD can be identified objectively.

  • 85.
    Mahbod, Amirreza
    KTH, School of Technology and Health (STH).
    Structural Brain MRI Segmentation Using Machine Learning Technique2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Segmenting brain MR scans could be highly benecial for diagnosing, treating and evaluating the progress of specic diseases. Up to this point, manual segmentation,performed by experts, is the conventional method in hospitals and clinical environments. Although manual segmentation is accurate, it is time consuming, expensive and might not be reliable. Many non-automatic and semi automatic methods have been proposed in the literature in order to segment MR brain images, but the levelof accuracy is not comparable with manual segmentation.

    The aim of this project is to implement and make a preliminary evaluation of a method based on machine learning technique for segmenting gray matter (GM),white matter (WM) and cerebrospinal uid (CSF) of brain MR scans using images available within the open MICCAI grand challenge (MRBrainS13).The proposed method employs supervised articial neural network based autocontext algorithm, exploiting intensity-based, spatial-based and shape model-basedlevel set segmentation results as features of the network. The obtained average results based on Dice similarity index were 97.73%, 95.37%, 82.76%, 88.47% and 84.78% for intracranial volume, brain (WM + GM), CSF, WM and GM respectively. This method achieved competitive results with considerably shorter required training time in MRBrainsS13 challenge.

  • 86.
    Malgerud, Lovisa
    KTH, School of Technology and Health (STH).
    Ett nytt arbetssystem för nutritionsmonitorering av geriatrikpatienter2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Background: The Swedish population is aging [1] and malnutrition is a common problem among elderly people [2]. A method called food registration is used to monitor the patients’ nutritional intake, with the purpose of reducing the risk of patients deteriorating in nutritional status during hospitalisation. However, the current method is not satisfactory and many food registration lists are incomplete. [3-6] Thus, patients do not receive a qualitative nutritional care since the assessment of the patients’ nutritional status is based on incomplete documentation.

    Purpose: The purpose of this master thesis is to increase the quality in the nutrition monitoring process in the geriatric units B72 and B74 at Karolinska University Hospital in Huddinge, Sweden. This should be done by increasing the prospects of providing caregivers with correct information about the patients’ nutritional intake and make the food registration more complete by introducing a new working system based on Lean Healthcare principles. The new working system should consist of a prototype of a food registration application and a new working approach with clear and standardised responsibilities for all occupational groups and shifts.

    Problem: Is it possible to create a visual and standardised working system that will increase the effectiveness and safety of the nutritional monitoring process?

    Methods: The current nutrition monitoring process was investigated by observations, interviews and timings. In addition, 100 registration lists were scrutinized and errors and missing information were noted and prototype of a food registration application was created using usability inspection methods. The prototype was tested in a usability test and evaluated in a survey that contained a standardised usability index called The System Usability Scale (SUS).

    Results: The review of old registration lists revealed that 59 per cent of the food registration lists missed information on how much the patient had been served and/or had consumed at one or more occasions. On average, each list contained 9.4 errors or points of missinged information. The SUS test generated a usability score of 86.75 out of 100, which is equivalent to an A in the A-F grading system. [7] During the usability test an average of 8.2 errors per test were made, though as 4.4 of these were corrected the net average was 3.8 errors per test. The three most common errors, which accounted for 69.5 per cent of all 82 errors, were to forget to specify quantity (36.6 per cent), to press ‘done’ before everything had been registered (18.3 per cent) and to not find the correct item (14.6 per cent).

    Conclusion: Hopefully, in the future, more food registrations will be correctly performed due to the built in mistake proofing systems of the food registration application and the introduction of the new working approach. The hope is that the new working system will provide caregivers with accurate information on the patients’ nutritional intake so that the patients’ nutritional care can be based on complete documentation. In this way, the quality and safety of the nutrition monitoring process will be increased.

  • 87.
    Marra, Marco Antonio
    KTH, School of Technology and Health (STH).
    Study of dens fracture in the elderly and the influence of osteoporosis with a finite element model2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Cervical spine injuries are a serious threat, as they may damage the central nervous system. In the elderly, cervical fractures due to falls are very frequent. The overall weakening of the bony and ligamentous spine decreases the resistance to fractures. Fractures of the dens of the second cervical vertebra (C2) are the most frequent individual fractures in the upper spine. Osteoporosis and impaired conditions play the main role in increasing the fracture risk. Several mechanisms may induce dens fractures: hyper-extension, lateral bending, shear, torsion, but the mechanisms of fractures have not been fully understood.

    Osteoporosis reduces overall bone strength. Cortical bone thinning occurs in the vertebræ, and there is a general loss of bone mass. Trabecular micro-architecture of bones loses integration, leading an increasing porosity. Mechanical properties worsen, and failure occurs more easily.

    In this study the role of osteoporosis on the genesis of dens fractures was investigated. An existing finite element (FE) model of the human spine was employed to simulate the effect of parameters associated with osteoporosis on the loading conditions of the dens. A baseline case was first simulated. Then, cortical thickness, cortical and trabecular bulk modulus and shear modulus were decreased in steps. Three impact scenarios were simulated: a lateral fall, a backward fall, and a forward fall. Effects of osteoporotic variations on the ligamentous spine deformations were studied. A mesh convergence analysis was performed to assess the influence of mesh size on the stresses in vertebra C2.

    The effect of reduced cortical and trabecular bulk moduli alone on stress distribution was not that apparent. In the dens, a reduced cortical thickness, in lateral and backward fall, caused higher maximum stresses than in the baseline. Conversely, in forward fall, reduced cortical thickness caused lower stresses than in the baseline. The effect of reducing trabecular bulk and shear moduli altogether was to decrease the stresses in dens trabecular bone. In lateral and backward fall, by reducing cortical bulk and shear moduli altogether, stresses in dens cortex decreased; whereas, in forward fall, stress decreased in dens neck cortex, and increased in dens apex and waist.

    It is concluded that cortical thinning, and reduced bulk and shear moduli of bone compartments considerably alter the stress distribution in C2, as well as the ligamentous spine response. The extent of such variations depends also on the impact scenarios. Finally, stresses in the model were found to be sensitive to the mesh size currently used in the human spine FE model.

  • 88.
    Mathay, Margaux
    KTH, School of Technology and Health (STH).
    Virtual planning of Total Knee Arthroplasty surgery: Assessment of implant positioning of different implanting types2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Increased workload on our healthcare system calls for more automation, this too in the pre-operative planning of total knee arthroplasty (TKA) surgery. This should keep in mind however that success in TKA is measured through having proper limb alignment. This thesis project implemented a virtual positioning assessment software that provides an initial position based on its bone and implant inputs with their specific landmarks. Positions can be furtherly adapted and evaluated based on flexion facets, obtaining decreased pre-operative workloads. The software was validated through an analysis comparison of the femur positioning of nine cases with the former used analysis tool of the university Hospital of Ghent. The newly implemented software was concluded to approximate the patients’ pre-operative alignment better for all translational and rotational parameters, except anteroposterior translation and internal/external rotation of the femur.

  • 89.
    Mecconi, Alessandro
    KTH, School of Technology and Health (STH).
    Dopamine replacement therapy reduces beta band burst duration in Parkinson’s disease2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    One of the main characteristics of Parkinson's disease (PD) is an exaggerated oscillatory activity in the beta band (12-30 Hz). This activity has been linked to the rise of symptoms such as bradykinesia and akinesia. Even if dopamine replacement therapy (oral intake of dopamine pro-drug levodopa) reverses these symptoms, the effect of the treatment on the beta band activity has still not been completely understood. Therefore, here the temporal dynamics of beta band activity in human patients affected by PD were characterized with and without levodopa treatment. Local-field-potential (LFP) recordings from five patients undergoing dopamine replacement therapy were used. From the LFPs, the extracted beta epochs with significantly higher power than expected from a comparable noisy signal were analyzed. This analysis showed that beta band activity occurred in bursts meaning that high amplitude oscillation alternated with silenced periods. The pathological state also distinguished itself for longer epochs and with power that increased with the length of the epoch. The administration of levodopa reduced the duration of bursts and decreased the overall mean power of the beta band activity. Finally, epochs with the same number of cycles were compared. The Coefficient of Variation prior such epochs suggested that the ongoing activity might lock into a synchronization process prior the burst. These results provide important information to better understand how levodopa alleviates some of the symptoms of PD and pave the way to develop better computational models for the emergence of beta oscillations.

  • 90.
    Mignérus, Elin
    KTH, School of Technology and Health (STH).
    Analysis of the neuronavigation market for development of a new technology: need validation and market aspects2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Neuronavigation is the technology used during brain surgery to verify the location in which the surgeon is working in terms of depth and width. Despite being considered to be helpful, the technology lacks when it comes to the consideration of brain shift, the dynamic changes of the brain during surgery. The purpose of this report was to verify the suspected need of an additional tool and investigate the market size and dynamics.

    The thesis work mainly followed the method of Biodesign – The process of innovating medical technologies, which covers all steps in the innovation process. To fit the specific purpose, the method was partly amended.The results of the report are divided into two categories – need and market. A need statement was developed and the market was mapped in terms of size and other players in the market space.

    The conclusions drawn are that there is a need for technology development in order to safely account for brain shift during tumour resection surgery, but that it is likely to be hard to enter the market due to other researchers who have made more progress in the area.

  • 91.
    Mohammadianrasanani, Seyedmehrdad
    KTH, School of Technology and Health (STH). University of Pennsylvania, Radiology Department .
    The use of a body-wide automatic anatomy recognition system in image analysis of kidneys2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 92.
    Mohammadianrasanani, Seyedmehrdad
    KTH, School of Technology and Health (STH). Royal Institute of Technology KTH STH, University of Pennsylvania.
    The use of a body-wide automatic anatomy recognition system in image analysis of kidneys2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 93.
    Monnot, Cyril
    KTH, School of Technology and Health (STH), Medical Engineering.
    Development of a data analysis platform for characterizing functional connectivity networks in rodents2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    AbstractThis document addresses the development and implementation of a routine for analyzing resting-state functional Magnetic Resonance Imaging (rs-fMRI) data in rodents. Even though resting-state connectivity is studied in humans already for several years with diverse applications in mental disorders or degenerative brain diseases, the interest for this modality is much more recent and less common in rodents. The goal of this project is to set an ensemble of tools in order to be able for the experimental MR team of KERIC to analyze rs-fMRI in rodents in a well defined and easy way. During this project several critical choices have been done, one of them is to use the Independent Component Analysis (ICA) in order to process the data rather than a seed-based approach. Also it was decided to use medetomidine as anesthesia rather than isoflurane for the experiments. The routine developed during this project was applied for a project studying the effects of running on an animal model of depression. The routine is composed of several steps, the preprocessing of the data mainly realized with SPM8, the processing using GIFT and the postprocessing which is some statistic tests on the results from GIFT in order to reveal differences between groups using the 2nd level analysis from SPM8 and the testing the correlations between components using the FNC toolbox.

     

  • 94.
    Monnot, Cyril Gerard Valery
    KTH, School of Technology and Health (STH).
    Development of a data analysis platform for characterizing functional connectivity networks in rodents2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This document addresses the development and implementation of a routine for analyzing resting-state functional Magnetic Resonance Imaging (rs-fMRI) data in rodents. Even though resting-state connectivity is studied in humans already for several years with diverse applications in mental disorders or degenerative brain diseases, the interest for this modality is much more recent and less common in rodents. The goal of this project is to set an ensemble of tools in order to be able for the experimental MR team of KERIC to analyze rs-fMRI in rodents in a well defined and easy way. During this project several critical choices have been done, one of them is to use the Independent Component Analysis (ICA) in order to process the data rather than a seed-based approach. Also it was decided to use medetomidine as anesthesia rather than isoflurane for the experiments.

    The routine developed during this project was applied for a project studying the effects of running on an animal model of depression. The routine is composed of several steps, the preprocessing of the data mainly realized with SPM8, the processing using GIFT and the postprocessing which is some statistic tests on the results from GIFT in order to reveal differences between groups using the 2nd level analysis from SPM8 and the testing the correlations between components using the FNC toolbox.

  • 95.
    Morén, David
    et al.
    KTH, School of Technology and Health (STH).
    Pehrs, Georg
    KTH, School of Technology and Health (STH).
    Study of Vehicle-to-Pedestrian Interactions with FEM – Evaluation of Upper Leg Test Methods using a Human Body Model2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The European New Car Assessment Programme (Euro NCAP) performs several different tests to evaluate vehicles and rate their safety. Some of these tests are subsystem tests made to mimic different body parts of a pedestrian in an interaction with a vehicle. However, some criticism to the test method for the upper leg has been presented, stating that there is a discrepancy between this test method and a real-life interaction. Therefore, a modified test method for the upper leg has been proposed.

    The aim of this thesis was to evaluate the upper leg test method used today by Euro NCAP, and compare it with the proposed modified test method as well as to computer simulations with a Human Body Model (HBM). The evaluation was performed by comparing different parameters obtained in the two test methods. These have also been compared to computer simulations using a HBM in interaction with a passenger vehicle model.

    Prior to the evaluation of the test methods, the HBM was positioned into different stances to mimic postures in the human walking cycle. The vehicle model was positioned at four different heights, and three different impact points along the bonnet were used. The results showed that the different methods had their own advantages for some parameters. However, no general conclusion of which method showed the closest correlation to the HBM reference simulations could be determined.

  • 96.
    Mozzi, Giuliana
    KTH, School of Technology and Health (STH).
    Finite Element Modeling of an Innovative Headband: A study about the headband design and its safety properties2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    One of the most recent challenges faced worldwide is the so-called “ageing population” phenomenon. Besides the disabilities and illnesses that the elderly is prone to, traumatic brain injuries represent a common and potentially fatal factor that greatly affects this population. Other subjects are however also likely to experience traumatic brain injuries i.e. people affected by some kinds of diseases and disorders such as epilepsy and dementia that are known to have a high risk of falling. Furthermore, sports accidents can also lead to traumatic brain injuries, for example cycling. Current solutions and devices for head injury prevention are limited and from a design point of view there is space for improvements. The focus of this master thesis is to model an innovative headband meant to be worn around the scalp during various daily life activities and in multiple situations. Its function is to prevent the wearer from traumatic brain injuries. The headband model is a finite element model, created in LS-PrePost. Subsequently, simulations are performed in LS-Dyna to replicate real life head impact scenarios. Different parameters and features of both the impacting condition and the headband are tested for creating the optimal headband structure for head injury prevention.

  • 97.
    Muhammad, Arif
    KTH, School of Technology and Health (STH).
    Iterative Reconstruction for Quantitative Material Decomposition in Dual-Energy CT2010Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    It is of clinical interest to decompose a three material mixture into its constituted substances using dual-energy CT. In radiation therapy, for example material decomposition can be used to determine tissue properties for the calculation of dose in treatment planning. Due to use of polychromatic spectrum in CT, beam hardening artifacts prevent to achieve fully satisfactory results. Here an iterative reconstruction algorithm proposed by A. Malusek, M. Magnusson, M.Sandborg, and G. Alm Carlsson in 2008 is implemented to achieve this goal. The iterative algorithm can be implemented with both single- and dual-energy CT. The material decomposition process is based on mass conservation and volume conservation assumptions. The implementation and evaluation of iterative reconstruction algorithm is done by using simulation studies of analyzing mixtures of water, protein and adipose tissue. The results demonstrated that beam hardening artifacts are effectively removed and accurate estimation of mass fractions of each base material can be achieved with the proposed method. We also compared our novel iterative reconstruction algorithm to the commonly used water pre-correction method. Experimental results show that our novel iterative algorithm is more accurate.

  • 98.
    Munkhammar, Tobias
    KTH, School of Technology and Health (STH).
    Ground Reaction Force Prediction during Weighted Leg Press and Weighted Squat in a Flywheel Exercise Device2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    When performing a biomechanical analysis of human movement, knowledge about the ground reaction force (GRF) is necessary to compute forces and moments within joints. This is important when analysing a movement and its effect on the human body. To obtain knowledge about the GRF, the gold standard is to use force plates which directly measure all three components of the GRF (mediolateral, anteroposterior and normal). However, force plates are heavy, clunky and expensive, setting constraints on possible experimental setups, which make it desirable to exclude them and instead use a predictive method to obtain the full GRF. Several predictive methods exist. The node model is a GRF predictive method included in a musculoskeletal modeling software. The tool use motion capture and virtual actuators to predict all three GRF components. However, this model has not yet been validated during weighted leg press and weighted squat. Furthermore, the normal component of the GRF can be measured continuously during the activity with pressure sensitive insoles (PSIs), which might provide better accuracy of the GRF prediction. The objectives of this thesis were to investigate whether force plates can be exluded during weighted leg press and weighted squat and to investigate whether PSIs can improve the GRF prediction. To investigate this, the node model and a developed shear model was validated. The shear model computes the two shear GRF components based on data from PSIs, an external load acting upon the body and data from a motion capture system. Both the node model and the shear model were analysed with two test subjects performing two successive repetitions of both weighted squat and weighted leg press in a flywheel exercise device. During the leg press exercise, the node model had a mean coeffcient of correlation (Pearson's) ranging from 0.70 to 0.98 for all three directions with a mean root mean square error ranging between 8 % to 20 % of the test person's body weight. The developed shear model had a coeffcient of correlation (Pearson's) between 0.64 to 0.99 and a mean root mean square error between 3 % and 21 % of the test person's body weight. This indicates that it is possible to exclude force plates and instead predict the GRF during weighted leg press. During squat, neither the node model nor the shear model provided accurate results regarding the mediolateral and anteroposterior components of the GRF, suggesting that force plates can not yet be excluded to obtain the full GRF during weighted squat. The results of the normal component during leg press was somewhat improved with the shear model compared to the node model, indicating that using PSIs can improve the results to some extent.

  • 99.
    Najar, salwan
    KTH, School of Technology and Health (STH).
    Simulering av 1-Wire sensorer2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The 1-wire bus is a communication bus system which is designed to provide data, signals and power over a single signal with low data rates, a high resolution and a long range. It is typically used to communicate with small inexpensive devices, as temperature sensors, which is worked as a slave with the master computer (PC).

    The 1-wire bus system provides the sufficient control and operation signal, a unique ID serial number of each sensor and it supports multiple temperature sensors by a driving power (Parasite Power) on single line.

    On the 1-Wire bus system, temperature sensors are supplied by two types of power supplies, external Power supply and Parasitic Power.

    The aim of this project is to program the microprocessor (Arduino) by using Arduino programming language to work as a temperature sensor type DS18B20 and also as a slave on the 1-Wire bus system.

    This report explains the 1-Wire bus system techniques and how the communication is achieved between the master and the slave (sensors) to measure the temperature values.

    The measured temperature values are collected from the output of each active sensor on the 1-Wire bus. These data are displayed by the personal computer (PC) which is worked as a master on the 1-Wire bus, and the data are represent the measured temperature values from twelve active sensors on the bus system.

    In this thesis, the temperature values from the 12 active sensors can be read and displayed on the master (PC) by using the following programs: Open Logger One Wire (OLOW) program, One Wire Viewer, DigiTemp and OWFS and I validated all the temperature values from these active sensors which are read and monitored by the drive bus programs. The comparison is done among the measured temperature values to see if the active sensors are given accurate temperature values with different drive bus programs.

    The project shows that the sensors can be connected in a network with the master, by using 1-Wire bus techniques. This thesis will be used by Karolinska University Hospital, and it can also be developed for different requirements in the future.

  • 100.
    Narangifard, Ali
    KTH, School of Technology and Health (STH).
    The multislice method in transmission electron microscopy simulation: An implementation in the TEM-simulator software package2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report introduces the multislice method for modeling the interaction between an electron and the atoms in the specimen (electron-specimen interaction). The multislice method is an approximation to the full quantum mechanical model for this interaction. After introducing the theory, we discuss how the multislice method is implemented and integrated into TEM-simulator, a software for simulation of Transmission Electron Microscope (TEM) images. 

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