This master thesis investigates the possibility of using machine learning methods to predict patient length of stay at the time of admission to a clinical ward from the emergency department. The main aim of this thesis is to provide a comparative analysis of different algorithms and to suggest a suitable model that can be used in a hospital prediction software. The results show that it is possible to achieve a balanced accuracy of 0.72 at the time of admission and of 0.75 at a later stage in the process. The suggested algorithm was Random Forest which combines good accuracy with effective training time, making it suitable for on-line use in a hospital. The study shows that there is a clear potential for the use of machine learning methods for predicting length of stay, but that further improvements have to be made before adaption into the healthcare. / Detta masterexamensarbete utforskar möjligheten att använda maskin-inlärning för att förutspå vårdtiden för en patient då denne skrivs in på en vårdavdelning från akutvårds-avdelningen vid ett sjukhus. Huvudmålet för arbetet är att tillhandahålla en jämförelse av olika maskininlärnings-algoritmer  och föreslå en algoritm som är lämplig att integrera i en mjukvara på sjukhuset. Resultaten visar att det är möjligt att nå en balanced accuracy på 0.72 vid inskrivningstillfället samt 0.75 vid en senare tidpunkt i vårdprocessen. Den föreslagna algoritmen var Random Forest som kombinerade bra prestanda med effektiv träningstid, något som gör den lämplig för att köras på sjukhuset. Projektet visar att det finns en tydlig potential för att använda maskininlärning för att prediktera vårdtid men att förbättringar krävs innan det kan nå hela vägen in i sjukhuset.

Existing method for the antibiotic susceptibility test (AST) requires 2-3 days to produce the result. For patients with urinary tract infection (UTI), this lengthy process is critical because they must bear the pain during this period. A newly proposed idea to shorten the time is by using phenotypic antibiotic susceptibility test (AST) method on single bacteria.The first step to achieve the goal is to design and fabricate a platform to capture single bacteria and remove unwanted particles. An integrated micro and nanomembrane structure fulfill the requirement. The micro membrane structure is used to capture intended particles and block larger particles, while nanomembrane is used to remove unwanted nanoparticles. Micro-membrane structure is designed as an array of the microwell, and each microwell is expected to capture the bacteria. The thickness of microwell must be comparable to the bacteria dimension to make the observation of single bacteria be possible. Otherwise, there will be a stack of bacteria and only the bacteria at the top can be observed.The nanoporous membrane is created using aluminum foil through the anodization process and microwell structure is created using OSTE polymer through photolithography. Both materials are inexpensive and the fabrication process is fairly simple. In the final result, the nanoporous membrane is successfully integrated with microwell array. Each microwell has diameter 200 µm and thickness 100 µm. The nanoporous membrane has pore diameters 70nm, thickness 200nm, and approximate porosity 24.6%.This project successfully produces a complete device by integrating microwell array, nanoporous membrane, and a device substrate. However, the desired thickness for the microwell array is not achieved. The thickness of the microwell is 100 µm while the size of a bacteria is only a few microns. Thin microwell array with 5 µm thickness is easily detached from the substrate during development. To solve this problem, a different mixture of developer solution is needed that will develop the OSTE but will not destroy the structure. Nevertheless, this early design of the platform is a promising start in the early development of rapid antibiotic susceptibility test (AST).

Fall-related incidents are the most common cause of injury among elderly, and may result in hip fractures. Svein Kleiven and Hans von Holst, professors at the Royal Institute of Technology, have developed a technology for a compliant flooring system with the intention of reducing the peak force acting on the proximal femur during a fall. A project is underway to make the floor commercially available, where this thesis was a part of the first phase of the project. The goal with this thesis was to modify a computational human body model (HBM) to predict hip fractures when falling, using different material and geometry regarding the flooring system. It was also to compile a set of requirements that the final product would need to fulfill. The human body model was validated and modified using a study where cadavers had been tested. With the Finite Element Method (FEM), impacts were performed with the human body model and a flooring system. Requirements regarding the flooring system were compiled using literature studies, a study visit in a geriatric care facility and dialogues with well-informed people. Modifications involving contacts, material and the proximal femur were made on the model. A total of 18 simulations were performed using different flooring systems. When compared to rigid floor condition, all configurations showed a reduction in peak force on the proximal femur. The maximal attenuation was calculated to 33.04%, provided by pins with a diameter of 3 mm and with a distance of 5 mm between their midpoints.

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.

Image quality in medical x-ray imaging is dependent on the characteristics of the x-ray photons produced  by  the  x-ray  tube,  the  detection  of  the  x-ray  photons  in  the  detector  and  the  image processing. X-ray image guidance during endovascular interventions is usually performed with C-arm fluoroscopy. It is of major importance that the image quality is sufficient for the procedure. The understanding of what affects the image quality could be made easier if the performance of the different parts of the system were to be judged separately, rather than considering the system as a whole.   The term Image QualityTube Output that is used throughout this thesis describes the image quality that only depends on the characteristics of the x-ray beam, such as spectral distribution and fluence, without the consideration of detector characteristics or image processing. The aim of this thesis was to  propose  a  method  to  evaluate  the  Image  QualityTube  Output  and  then  compare  two  different fluoroscopy systems used for endovascular interventions with respect to Image QualityTube  Output, patient dose and personnel exposure, all as a function of patient thickness.   To limit to the x-ray tube output a third x-ray system was used. In that way detector and image processing would be the same and the differences in image quality would only be due to the tube output. The imaging parameters set by the Automatic Dose Rate Control, ADRC, for various patient thicknesses, was found by using Polymethyl-methacrylate, PMMA, as patient. A test object was introduced and exposed together with the PMMA of varying thickness, using the parameters set by the ADRC. The images were evaluated with respect to low contrast sensitivity and contrast to noise ratio, CNR. The effective dose rate to the patient was calculated using Monte Carlo simulation. Finally, the personnel exposure was measured using active dosimeters. The  results  showed  differences  in  the  systems  performance  and  Image  QualityTube  Output.  Also interesting differences in the effective dose rate to the patient was found. Altogether the results indicate that the proposed method is a feasible way to compare the Image QualityTube Output of two fluoroscopic systems.

Instruction manuals are supposed to be used to ensure safe and proper use of medical devices. The instruction manuals could be paper or digital docu- ments, animations or videos. Conveying information and instructions through these media might not be the most efficient approach, especially in healthcare where physicians and nurses experience high cognitive load and prefer hands-on experience with the devices [1]. This thesis investigates how a possibly more efficient and intuitive instruction manual could be developed using mobile marker-based Augmented Reality; a technology that combines a virtual and physical world. By analyzing and comparing different marker-based Augmented Reality sys- tems and Software Development Kits (SDKs), the most suitable system, in terms of availability and functionality, was chosen for the implementation. Two mobile AR instruction manual prototypes were developed, as a proof-of-concept, using Unity3D with Qualcomm’s Vuforia extension. The resulting prototypes demonstrate the opportunity to integrate informa- tion and instructions in our physical world and the difficulties associated with the interaction and user experience with the relatively novel Augmented Reality interface.

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