In Dynamic Contrast Enhanced MRI there are several steps from the initial signal to obtaining the pharmacokinetic parameters for tumor characterization. The aim of this work was to validate the steps in the flow of data focusing on T1-mapping, Contrast Agent (CA)-quantification and the pharmacokinetical (PK) model, using a digital phantom of a head. In the Digital Phantom tissues are assigned necessary values to obtain both a regular and contrast enhanced (using Parker AIF) representation and simulating an SPGR signal. The data analysis was performed in a software called MICE, as well as the Digital Phantom developed at the department of Radiation Sciences at Umeå University. The method of variable flip angles for the T1-mapping was analyzed with respect to SNR and number of flip angles, finding that the median value in each tissue is correct and stable. A "two point" inversion recovery sequence was tested with optimal combination of inversion times for white matter and CSF and obtaining correct T1-values when the inversion times were close to the tissue T1, otherwise with large deviations seen. Three different methods for CA-quantification were analyzed and a large underestimation was found assuming a linearity between signal and CA-concentration mainly for vessels at about 60%, but also for other tissue such as white matter at about 15%, improving when the assumption was removed. Still there was a noticeable underestimation of 30% and 10% and the quantification was improved further, achieving a near perfect agreement with the reference concentration, taking the T2*-effect into account. Applying Kety-model, discarding the vp-term, Ktrans was found to be stable with respect to noise in the tumor rim but ve noticeably underestimated with about 50%. The effect of different bolus arrival time, shifting the AIF required in the PK-model with respect to the CA-concentration, was tested with values up to 5 s, obtaining up to about 5% difference in Ktrans as well as the effect of a vascular transport function obtained by the means of an effective mean transit time up to 5 s and up to about 5% difference in Ktrans.

The use of non-ionizing radiation in the magnetic resonance imaging (MRI) made it a safer diagnostic technique in comparison to the X-ray imaging method. MRI can also produce soft tissue images with a very high contrast without contrast agent which is another advantage that made MRI an important imaging technique for studying the mechanism of the deep brain stimulation (DBS) and for targeting the desired regions in the brain that should be stimulated. For these and other advantages, the number of MRI examinations have increased hugely around the world including Sweden. Despite the consideration that MRI is a safe modality, it is not free from risks and hazards. The radiofrequency (RF)-induced heating of the tissues and the metallic implants is one of the safety concerns in MRI which certainly includes patients with DBS implant.The purpose of this project, motivated by the dangers accompanying the RF-induced heating in implantable DBS lead, is to investigate the effect of the exposure to the RF fields in MRI on these leads. After temperature measurements were made, the observations were focused on the amount of temperature increase, and the time required for the temperature to increase and then to decrease to its initial value. Some factors that could affect the lead temperature were studied and that includes the effect of the lead configuration, the lead surrounding medium, the exposure level, and the orientation of the lead coil with respect to the RF field.The result showed that the temperature of the lead (placed in air) increased more but slower when the lead was formed as a coil than when it was randomly configured. It was also showed that the lead coil temperature rise was higher and faster when the coil was placed in air than when it was immersed in deionized water or in saline. The lead coil temperature rise was higher, but slower when the coil was immersed in saline compared to deionized water. Also, exposure level affected the temperature rise such that the higher exposure level showed higher and faster temperature rise of the lead coil. When the lead coil was placed in air and oriented perpendicular to the strongest magnetic field component, its temperature increased higher and faster. On the other hand, the results when the lead coil was immersed in deionized water or in saline showed a deviation from when it was placed in air such that two magnetic field components had the same effect on the lead coil temperature. The time required for the temperature to decrease to its initial value, after the end of the exposure, depended on the magnitude of the RF magnetic flux density, orientation of the lead coil with respect to the RF magnetic field, and the lead surrounding medium. The stronger RF magnetic field is, the longer time is for the temperature to decrease. Consequently, when the lead coil was directed perpendicularly to the strongest component of the RF magnetic field, it took longer time for the temperature to decrease. The time for the temperature to decrease was longer when the lead coil was immersed in water (deionized or saline) than when the lead coil was placed in air. It also took longer time for the temperature to decrease when the lead coil was immersed in saline than in deionized water.

Studies have reported that around 20 % of all traffic accidents are caused by a sleepy driver. Sleepy driving has been compared to drunk driving. A sleepy driver is also an issue in the case of automated vehicles in the future. Handing back the control of the vehicle to a sleepy driver is a serious risk. This has increased the need for a sleepiness estimation system that can be used in the car to warn the driver when driving is not recommended. One commonly used method to estimate sleepiness is to study the heart rate variability, HRV, which is said to reflect the activity of the autonomous nervous system, the ANS. The HRV can be expressed through different measures obtained from a signal of RR-intervals. The aim with the thesis is to investigate how well the HRV translates into sleepiness estimation and how the experimental setup might affect the results. In this study, HRV data from 85 sleep deprived drivers was collected together with the drivers’ own ratings of their sleepiness according to the nine graded Karolinska sleepiness scale, KSS. An ANOVA test showed statistical significance for almost all of the used HRV measures when the Driver ID was set as random variable. In order to reduce the number of HRV measures, a feature selection step was performed before training a Support Vector Machine (SVM) used for classification of the data. SVM classifiers are trained to use the input features describing the data to optimize hyperplanes separating the discrete set of classes. Previous research has shown good results in using HRV for sleepiness detection, but common issues are the small data sets used and that most experiments are performed in a simulator instead of at real roads. In some cases, no sleep deprivation is used. The result from the classification in this study is a mean accuracy of around 58-59 %, mean sensitivity of 50-51 %, mean specificity of 75-76 % and mean F1 score of 50-51 % over the three classes ’Alert’, ’Getting sleepy’ and ’Sleepy’. This together with the results of the ANOVA test shows that the HRV measures performed relatively poor when used for classification of the data and that there are large inter-individual differences. This suggests the use of personalized algorithms when developing a sleepiness estimation system and an investigation regarding how other confounding factors could affect the estimation is also motivated.

Vid behandling med Peritonealdialys behöver patienten utföra ett moment där de kopplar samman sin inopererade kateter till en extern dialyspåse. Detta moment innebär stora risker för allvarliga infektioner på grund av kontaminering av känsliga delar. Mitt examensarbete syftar till att göra momentet säkrare och tryggare för patienten genom att minimera den risken. Jag ville skapa ett hjälpmedel som fortfarande engagerar patienten i kopplingsmomentet och håller ner kostnaden genom att designa kring redan befintliga dialysprodukter och undvika avancerad mekanik. Projektet tar avstamp från min tidigare erfarenhet som sjuksköterska och de observationer jag gjort rörande den här behandlingstypen / During treatment with Peritoneal dialysis the patient needs to perform a specific task of connecting their surgically placed catheter to an external bag of dialysis fluids. This specific task implicates big risks of serious infections due to contamination of sensitive parts.  My exam project aims to make this connection safer for the patient by minimizing these risks. I wanted to design a tool that aids the patient and at the same time engage them in the connection process. To keep the costs down I chose to design around already existing dialysis components and to avoid advanced mechanics. This project takes off on my previous experience as a nurse and the observations I made regarding this treatment method.

Around the world, people are becoming more sedentary and less physically active. These behaviors are two examples of habits causing lifestyle diseases and premature death. The Health Dialogue (Hälsosamtal) is a method used in Sweden today, which attempts to prevent people from being diagnosed with lifestyle caused diseases. Today, the Health Dialogue does not offer an opportunity to perform follow-up of lifestyle goals created during the Health Dialogue, which is an important missing piece of the method. Follow-up regarding goals can benefit from being combined with digital twin technology, since this type of technology can potentially prevent negative habits by providing personalized predictions of bodily functions. In this thesis, a design prototype was created, combining the Health Dialogue with digital twin technology as an attempt to increase motivation towards a healthier lifestyle. Three hypotheses were proposed and evaluated through a user test containing the created design prototype. The results of the evaluation showed some support for the hypotheses for some participants, but overall, not enough to show support for motivation while using the prototype. However, the design and evaluation method can help in further development of an application that might contribute to motivation of a healthier lifestyle in the future.

Motion capture has in recent years grown in interest in many fields from both game industry to sport analysis. The need of reflective markers and expensive multi-camera systems limits the business since they are costly and time-consuming. One solution to this could be a deep neural network trained to extract 3D joint estimations from a 2D video captured with a smartphone. This master thesis project has investigated the accuracy of a trained convolutional neural network, MargiPose, that estimates 25 joint positions in 3D from a 2D video, against a gold standard, multi-camera Vicon-system. The project has also investigated if the data from the deep neural network can be connected to a biomechanical modelling software, AnyBody, for further analysis. The final intention of this project was to analyze how accurate such a combination could be in golf swing analysis. The accuracy of the deep neural network has been evaluated with three parameters: marker position, angular velocity and kinetic energy for different segments of the human body. MargiPose delivers results with high accuracy (Mean Per Joint Position Error (MPJPE) = 1.52 cm) for a simpler movement but for a more advanced motion such as a golf swing, MargiPose achieves less accuracy in marker distance (MPJPE = 3.47 cm). The mean difference in angular velocity shows that MargiPose has difficulties following segments that are occluded or has a greater motion, such as the wrists in a golf swing where they both move fast and are occluded by other body segments. The conclusion of this research is that it is possible to connect data from a trained CNN with a biomechanical modelling software. The accuracy of the network is highly dependent on the intention of the data. For the purpose of golf swing analysis, this could be a great and cost-effective solution which could enable motion analysis for professionals but also for interested beginners. MargiPose shows a high accuracy when evaluating simple movements. However, when using it with the intention of analyzing a golf swing in i biomechanical modelling software, the outcome might be beyond the bounds of reliable results.

To compete with other manufacturing companies in the market, product design and manufacturing methods need to be improved constantly. To save time and money, there is an advantage if there is a manufacturing plan in place before designing the final product. Composites have been used worldwide for over 6,000 years and their use is expected to increase in the future. Composites offer advantages in product design and manufacturing since it can be adapted to the intended purpose.  The purpose of the project is to determine whether it is possible to produce a magnetic polymer composite with a sufficiently high magnetism to lift a specific weight. The purpose is fulfilled through practical executions together with a literature study to find out which materials were most suitable for the application. The polymer composites were tested in magnetic tests to see if a sufficiently high magnetism was obtained to lift the specific weight.  Two steel powders, differing in particle structure and density, were mixed with an epoxy as a binder and then cast in two different moulds with a depth of 2 mm and 4 mm. The proportions of the steel powder were tested from 50% up to 97%. The result showed that sufficiently high magnetism to lift the intended weight was reached at a concentration of steel powder between 85% - 97%. The composites did not exhibit the necessary magnetic capacity to function in the intended application and therefore further tests with a magnetic material with higher relative permeability are proposed. / Syftet med arbetet är att undersöka om det går att framställa en polymerkomposit med tillräcklig magnetisk kraft för att lyfta en skiva som väger 100g. Polymerkompositen ska tillverkas genom gjutning. De parametrar som behöver tas hänsyn till i arbetet är vilka material som är lämpliga att använda i kompositen, vilka proportioner av plast- och magnetiskt material som behövs för att skapa tillräcklig magnetisk kraft och den magnetiska kraft som polymerkompositen behöver erhålla för att lyfta skivan. Materialvalet är en viktig aspekt i arbetet för att uppnå önskat resultat. Det magnetiska materialet behöver ha en hög relativ permeabilitet, det vill säga en hög grad av förmågan att magnetisera sig själv med ett pålagt externt magnetfält, för att uppnå tillräcklig magnetisk kraft. Vid val av polymermaterial är det viktigt att ta hänsyn till materialets viskositet, med andra ord, materialets tjockhet. Det med anledning för att en lägre viskositet hos polymeren tillåter högre koncentration av metallpartiklar. Vilket är önskvärt för att få in så mycket magnetiskt material som möjligt i polymerkompsiten. Proportionerna av de två materialen behöver anpassas efter dess egenskaper för att uppnå en önskad magnetisk kraft. Ett magnetiskt material som har en hög relativ permeabilitet behöver till exempel blandas med ett polymermaterial med högre viskositet för att blandningen inte ska sedimentera.   Kompositer har använts i hela världen i över 6000 år och användningen förväntas att öka under framtiden. Grunden till detta projekt är att en stålbricka med magnetiska egenskaper ska bytas ut mot en magnetisk polymerkomposit i ett instrument. Fördelen med en komposit är möjligheten att anpassas efter ändamålet och därför till exempel kan vara lättare, tåligare, flexibla och motstå korrosion.  Genom praktiska undersökningar tillsammans med en litteraturstudie uppfylls syftet att ta reda på lämpliga material och proportioner. Avslutningsvis ska de gjutna polymerkompositerna testas i magnetiska tester för att undersöka om tillräckligt hög magnetism kan erhållas för att lyfta den specifika vikten. I arbetet används två stålpulver som skiljer sig i partikelstruktur och densitet, dessa stålpulver blandas med bindemedlet epoxi och gjuts därefter i två olika formar med djupet 2mm och 4mm. Proportionerna i vikt för stålpulvret testades från 50% upp till 97%. Resultatet visade att tillräckligt hög magnetism för att lyfta avsedd vikt nåddes vid en koncentration av stålpulver mellan 85% -97%. Resultatet visade inte tillräckligt hög magnetism för att fungera i den avsedda applikationen och därför föreslås vidare tester med ett magnetiskt material med högre relativ permeabilitet.

Background: Lately, barefoot running has become popular and there is a debate on the pros and cons of barefoot running with regards to running injuries. Many factors are causing injuries and one of the factors discussed is the fact that we run in shoes. When we run in shoes the biomechanics of the running technique may and therefore be a possible cause to injury. Aim: The aim of the study was to assess how the foot strike pattern, angle of the knee and ankle joint at time of initial contact, as well as the step length changes between a shod and barefoot running condition in habitually shod runners when running in a pace equivalent to their running pace over ten kilometers. Method: Twenty-seven healthy runners (18 male, 9 female) were included in the study. The study took place at the fitness center of Halmstad University. Subjects ran on a treadmill, in an individual pace equivalent to their running pace over ten km, both in a shod and barefoot running condition. Two-dimensional analysis of the sagittal plane kinematics of the knee joint, ankle joint and foot position to horizontal, foot strike pattern and step length was done. Participants ran for ten minutes with shoes and for five minutes barefoot. Running technique was videotaped using an Iphone 6 camera and landmarks were marked with white tape to ease the analysis. Results: Changes in foot strike pattern was observed. When running barefoot 63% of the subjects adopted a non-heel strike pattern compared to 18.5% when shod (p=0.001). Knee flexion was increased at IC for the barefoot condition, with 164°±6 relative knee angle compared to 167°±6 when shod (p=0.001). Ankle angle at IC did not show a statistical significant difference between conditions (p=0.657). When barefoot the angle was 117°±8 compared to 115°±8 when shod. Foot angle to horizontal showed a flatter foot placement at IC with a less dorsiflexed foot for the barefoot condition (-4°±8) compared to shod (-12°±8), (p=0.001). Step length was decreased for the barefoot condition (0.82m ±0.15)   compared to shod (0.85m ±0.13), (p=0.008). Conclusion: Results are consistent with previous findings that barefoot running in some cases change the running technique with a flatter foot placement, an increased knee flexion at IC and a decreased step length. However, caution must be taken when habitually shod runners transition to barefoot running in regards to the biomechanical changes that may occur. To benefit from barefoot running a non-heel strike pattern is required. Further, the running technique may be the more important factor, regardless of wearing shoes or not.

På CBH (Skolan för kemi, bioteknologi och hälsa) har en mikro-CT utvecklats, men med förbättringspotential gällande användbarheten. Målet med kandidatexamensarbetet var att förbättra mjukvaran genom att automatisera tre olika aspekter av manuell datahantering: Dels att placera filerna i en mapp med namn kopplat till valda bildtagningsinställningar. Dels att kopiera data via SCP mellan två datorer kopplade till mikro-CT:n. Samt att radera kopierade data från disken som preliminärt sparar filerna. För att möjliggöra en automatisk dataöverföring implementerades ett SSH-nyckelpar med publik nyckelautentisering mellan de två datorerna. Till den befintliga mjukvaran tillades ett skript samt en klass med handhavande över de tre automatiseringsaspekterna. Genom användargränssnittet hämtar klassen inledningsvis information om bildtagningsinställningarna till mappnamnet och när bildtagningen är klar anropar programkoden skriptfilen som utför SCP-kopieringen. Därefter kontrolleras att inga data gått förlorade under överföringen, varefter en radering av de kopierade filerna utförs på den ursprungliga disken. Den nya klassen förbättrar mikro-CT:ns användarvänlighet och underlättar hanteringen av data efter en bildtagning. / At CBH (The School of Engineering Sciences in Chemistry, Biotechnology and Health) a micro-CT has been developed, but the system has potential improvement regarding the usability. The purpose of this bachelor’s thesis was to improve the software by automatizing three aspects of manual data handling: Firstly to place the data in a folder with a name related to the obtained acquisition settings. Secondly to transfer files through SCP between the two computers connected to the micro-CT. Lastly to delete the copied data from the disk that initially saves the files. In order to automate the data transfer an SSH key pair with public key authentication was implemented between the two computers. To the existing software a script as well as a class controlling the three automation aspects were added. From the user interface, the class initially retrieves information about the acquisition settings to the folder name and when the acquisition is complete, the program code calls the script file that performs the SCP transfer. Afterwards a verification is made that no data was lost during the transfer, after which a deletion of the copied files is performed on the original disk. The new class improves the usability of the micro-CT and facilitates the handling of data after an acquisition.

Europeiska unionen röstade igenom nya regelverk för medicintekniska produkter och för medicintekniska produkter för in vitrodiagnostik 2017. Regelverken implementerades 2021. De nya regelverken innebär striktare krav på tillsyn, klinisk prövning och spårbarhet, för att stärka patientsäkerheten. Målet med projektet var att undersöka om vårdcentralerna inom Stockholm läns sjukvårdsområde (SLSO) uppfyller de nya regelverken och sedan ta fram en analysmodell och analysera hur väl de anpassar sig till regelverken. För att säkerställa att SLSO:s vårdcentralerna uppfyller de nya regelverken utfördes i detta projekt fysiska inventeringar på tio slumpmässigt utvalda enheter som inte har befintliga serviceavtal med leverantörer eller servicegivare. Det visade sig att på samtliga enheter nyttjas konsumentprodukter till patienter, som inte är avsedda för medicinskt bruk. Flertalet enheter saknade även produkter som bör finnas tillgängliga. Överlag var enhetscheferna på vårdcentralerna inte insatta i de nya regelverken och visste inte att produkterna de använde inte är avsedda för sjukvård. De hade även flera produkter som var gamla och/eller trasiga som användes på daglig basis vilket inte uppfyller kraven på patientsäkerheten. Slutsatsen blev därför att SLSO:s vårdcentraler inte uppfyller de nya regelverken. / The European Union voted through new regulations regarding medical devices and medical devices for in vitro diagnostics in 2017. These new regulations were implemented in 2021. The new regulations entailed stricter supervision, clinical testing, and traceability requirements to strengthen patient safety. To ensure that care centers within Region Stockholm comply with the new regulations, physical inventories were carried out at ten randomly selected units that do not have existing service agreements with suppliers or service providers. To compare different units’ individual adaptations to the regulations, an analysis model was created in which the proportion of products that were not approved for medical use and the lack of certain necessary equipment were factors. In all units, consumer products are used for patients, which are not intended for medical use, and several units lack products that should be available. Overall, the unit managers at the care centers were unfamiliar with the new regulations and were unaware that the products they used were not intended for healthcare. The care centers also had several old and/or broken products that were used daily, which does not meet the requirements for patient safety. The conclusion was therefore that the care centers in Region Stockholm do not comply with the new regulations.