Datorn är ett viktigt verktyg i vår vardag. För rörelsehindrade kan datorn vara en förutsättning för att kunna fungera i vardagen. Datorn har som tekniskt hjälpmedel gett funktionshindrade större möjligheter till meningsfulla aktiviteter, såsom att på egen hand skriva, läsa och kommunicera. Samtidigt är det inte alltid funktionshindrade klarar av att använda vanliga datorer utan behöver alternativa inmatnings- och styrenheter. Målet med denna licentiatavhandling har varit att utveckla tekniker som ska stödja personer med rörelsebegränsningar. Främst har arbetet varit att utveckla alternativa tekniker för att kunna manövrera en dator. Viktiga aspekter i arbetet har varit att göra hjälpmedlen användarvänliga, möjliga att individanpassa, och att ta tillvara de tänkta användarnas synpunkter kring behov och önskemål. Vidare har inmatningsenheten utvärderats av användare och även tillämpats som ett rehabiliteringsverktyg för en mindre patientgrupp med nackskador, så kallade pisksnärtskador. Utöver dessa vetenskapliga mål har produktionsaspekterna varit viktiga. För att säkerställa att enheten ska kunna bli en produkt måste den kunna produceras och säljas till ett rimligt pris och detta måste beaktas under hela utvecklingsprocessen. En alternativ datormus baserad på MEMS-gyroskop har utvecklats. Utvecklingen är gjord utifrån de krav de tilltänka användarna ställde på den alternativa datormusen och enheten är utprovad och förbättrad i en iterativ process mellan utvecklare och användare, så kallad användarcentrerad utvecklingsprocess. MEMS-gyron var den typ av rörelsesensor som bäst svarade mot de krav som ställdes på enheten. De användare som deltog vid ett längre fältprov var samtliga nöjda och ville behålla musen. För att underlätta processen att välja rätt typ av gyro och att kunna utvärdera deras stabilitet under olika omgivningsfaktorer, såsom temperatur och vibrationer, har en testrig för gyron utvecklats. Människors rörelsemönster skiljer sig från industriella tillämpningar och därför behövs en speciell testrigg. Testriggen roterar gyron och mäter sensorsignalen under olika betingelser. Flera gyron kan testas samtidigt och testdatat kan sparas och analyseras i efterhand. Ett interaktivt datorbaserat träningsprogram har utvecklats och utvärderats vid en pilotstudie tillsammans med den alternativa datormusen. Syftet var att låta nackskadade utföra huvudrörelser och få en feedback på att de tränar rätt. Resultatet pekar på att detta kan vara en lovande metod. / Computers are important tools. People with motion disabilities sometimes are dependent on a computer and used as a technical aid the computer has improved the possibilities to perform meaningfull tasks, as writing, reading and communicating. However, disabled often need an alternative input device to control a computer.   The aim with this licentiate theses has been to develope techniques to support persons with motion limitations. Focus has been to develope alternative techniqes to control a computer. Important aspects have been user-friendlieness, possiblilities to perform individual adaptions and incorporatation of specifications from the intended users. Further, the input device has been evaluated by users and applied as a rehabilitation tool for a smaller patient group of persons with whiplash associated disorders.   Further, production aspects are important. To make the unit into a product, it has to be possible to produce and sell to a reasonable price. This has to be considered during the whole development process.   An alternative computer mouse based on a MEMS gyroscope has been developed. The specifications made by the users has been used as a starting point in the development and the unit has been evaluated and improved in an iterative process, so called user centric development. MEMS-gyros were the type of motion sensors most corresponding to the demands. The users that participated in a longer field test were all satisfied and wanted to keep the mouse.   To improve the process to choose right kind of gyro and to be able to evaluate their stability depending on factors as temperature and vibration, a test-rigg for gyros has been developed. Human motion pattern differs from industrial applications and therefor a special test-rigg was needed. The testrigg rotates the gyros and measures the sensor signal. Several gyros can be tested simultaneously and data can be stored and analysed afterwards.   An interactive computerbased training program has been developed and evaluated in a pilot study together with the altrenative computer mouse. The aim has been to let people with neck injuries perform head motions and get feedback that they perform the right kind of training. The result is promising.

Många små företag upplever svårigheter att finansiera företaget under uppstarten, det krävs både kontakter, tur och tålamod för att lyckas. Att finna finansiering är ofta ett omfattande och tidsödande arbete för småföretagaren. Medicintekniska företag tillverkar ofta forskningsbaserade produkter och har ett stort kapitalbehov långt innan de kan visa upp en färdig produkt eller försäljningsintäkter. Detta är ett stort problem då externa finansiärer helst inte vill riskera för mycket vid en investering och föredrar att investera i ett senare skede. Syfte: Syftet med uppsatsen är att ta reda på vilken attityd småföretag i medicintekniska branschen har på externt kapital samt i vilken utsträckning det används för finansiering av företagen i introduktionsfasen. Teori: Finansieringsteori och tidigare forskning kring finansiering av småföretag samt riskkapital har studerats för att skapa en teoretisk referensram. Metod: En kvalitativ metod användes och undersökningen bygger på intervjuer med åtta små medicintekniska företag, en affärsinkubator och en investerare. Vid analysen användes en deduktiv ansats och teorier och modeller testades mot det empiriska underlaget. Resultat och analys: Finansieringen under uppstarten består till största delen av offentlig finansiering och riskkapital. Företagen har en lång introduktionsfas då det tar lång tid att ta en produkt till marknad. Det förekommer gap mellan företag och investerare av olika karaktär, förväntningsgap, informationsgap och skillnad i målsättning är några. Det är relativt lätt att få de små belopp som krävs för att starta ett företag men småföretagen har sedan svårt att komma över tröskeln hos riskkapitalbolagen då de söker ett för litet kapitalbelopp. Slutsatser: Offentlig finansiering är betydande för företagen. Det stora kapitalbehovet gör det nödvändigt att finansiera företaget med riskkapital. Riskkapital bidrar förutom rent finansiellt med kompetens och kontakter. Trots att investerare helst vill investera i senare faser kan dessa företag attrahera externt kapital.

Left ventricular pumping performance may be described by intraventricular pressure and volume variables, usually presented as a pressure-volume plot. However, on-line monitoring of left ventricular pressure and volume with high temporal resolution requires the use of an invasive catheter technique such as, for example, the conductance catheter method. On the other hand, the very invasiveness and complexity of this approach makes it less suitable for clinical use. It is then not surprising that there has been long-felt need to make the conductance method less invasive and attempts have been made to adjust the method to clinical demands and routine in order to extract more information from pressure-volume interplay and possibly translate relevant data to their non-invasive estimates. In the present studies, a standard five segmental conductance catheter was used in animal (pig) experiments. Segmental conductances were compared to global conductance. Since the mid-ventricular segment was shown to reflect global volume, which was also shown on theoretical basis, it was concluded that a single segmental catheter most probably could be used to estimate global left ventricular volume. Subsequently, a thin and flexible single segmental conductance catheter was constructed and applied to an animal (pig) experimental model. Results were reproducible and very few arrythmias were detected. At the next stage, left ventricular isovolumic phases were investigated using the standard conductance catheter method, as well as echocardiographically derived tissue velocity doppler. Conductance was shown to decrease during isovolumic contraction, and an adjustment method was proposed in order to account for the subsequent decrease in pressure-volume loop area. In separate experiments, the left ventricular pressure wave form during left ventricular systole was examined, and an algorithm was proposed to discriminate between the changes in afterload, preload and contractility. Results showed clearly discernible patterns of the respective load and contractility alternation. Finally, the left ventricular continuous area was monitored continuously during the entire cardiac cycle as a measure of left ventricular volume dynamics in normal subjects and three patients with left ventricular abnormalities using echocardiographic automatic boundary detection. The left ventricular area thus obtained was plotted against its first derivative, to form a flow-volume estimates loop, in accordance with the flow-volume examinations used in respiratory physiology. Data obtained from the abnormal ventricles were presented as flow-volume estimates loops, exemplifying the possible use of the method. / QC 20100922

Arbetets syfte var att utreda reliabilitet och validitet för en blickregistreringsutrustning, JAZZ™, som finns på FOI i Linköping. Dessutom skulle utredningen klargöra huruvida utrustningen kan användas till att detektera mental arbetsbelastning. Tre olika studier gjordes på 17 försökspersoner. Endast sackader i horisontalled studerades, trots att utrustningen har ett flertal andra mätområden. Första studien utredde utrustningens reliabilitet och validitet, om JAZZ™ mätte det som avsågs (i det här fallet sackader i horisontalled) samt om mätningarna var konsekventa från ett försökstillfälle till ett annat. Den andra och tredje studien behandlade mental arbetsbelastning. Även subjektiva bedömningar togs med i utredningen då försökspersonerna fick svara på en enkät efter varje genomfört försök. Statistiska resultat visade bland annat signifikanta skillnader mellan de olika studierna och inga signifikanta skillnader mellan de inbördes försöken, vilket indikerar att JAZZ™-utrustningen är reliabel och valid. Tillsammans med de subjektiva bedömningarna kan det också påvisas att utrustningen kan detektera mental arbetsbelastning.

Adipose tissue volume and distribution is related to metabolic diseases such as diabetes and atherosclerosis. This relationship is in focus for much research, much due to a worldwide increase in obesity. It is in many cases of interest to calculate the amount of adipose tissue in different compartments within the body. Commonly used methods are however prone to introduce errors due to partial volume effects. Previous studies have successfully segmented three adipose tissue compartments from abdominal two-point Dixon fat-water MRI volumes using Morphon registration and atlas segmentation. This thesis extends upon the previous work by enabling segmentation of whole-body MRI volumes and by improving the registration with the use of both fat and water data. Possible methods for bone marrow segmentation are also tested and evaluated. The methods presented seem to be sufficient for creating whole-body volumes from a set of smaller volumes. The adipose tissue segmentation was adequate for subjects with relatively small volumes of adipose tissue, whereas segmentation of subjects with large amounts of adipose tissue require further improvement. Of the evaluated methods for bone marrow segmentation one seemed to perform adequately on all the tested datasets. Due to the few datasets available for testing it was not possible to draw any general conclusions as to how well the presented methods perform.

För att ta reda på hur svenska mammografiavdelningar står sig mot det europeiska protokollet undersöks nio mammografiavdelningar. Till hjälp har ett CDMAM-fantom version 3.4 och fyra plexiglasskivor använts för att simulera ett normaltjockt bröst. Även ljusskåpen och filmens egenskaper har undersökts och jämförts med kraven i europeiska protokollet. Avgränsningar har gjorts då koncentreringen ligger på mammografer som använder sig av film-skärm system. Röntgenbilderna har studerats utan tekniska hjälpmedel. Efter bedömning och poängsättning av bilderna på CDMAM-fantomet har värdena förts in i ett Excel-program där värdena presenteras i grafer. Från graferna utvärderas om bildkvaliteten ligger inom gränserna som anges för bra bildkvalitet. Det är endast ett av sjukhusen som ligger inom gränsen för bra bildkvalitet. Jämförelser har gjorts för att undersöka hur filmens egenskaper påverkar bildkvaliteten och om stråldosen har betydelse för bildkvaliteten. Samma sjukhus som har den högsta stråldosen har också den bästa bildkvaliteten.

Fixed-collision correlated sampling for Monte Carlo (MC) simulations is a method which can be used in order to shorten the simulation time for brachytherapy treatment planning in a 3D patient geometry. The increased efficiency compared to conventional MC simulation is measured by efficiency gain. However, a previous study showed that, in some cases, PDFs (probability density functions) of estimates of the efficiency gain, simulated using resampling and other MC methods, were multimodal with values below 1. This means that the method was less effective than conventional sampling for these cases. The aims of this thesis were to trace the causes of the multimodal distributions and to propose techniques to mitigate the problem caused by photons with high statistical weights.Two simulation environments were used for the study case, a homogeneous and a heterogeneous environment. The homogenous environment consisted of a water sphere with the radius 100mm. For the heterogeneous environment a cylindrical block of tungsten alloy (diameter 15 mm, height 2.5 mm) was placed in the water sphere. The sphere was divided into an array of cubic voxels of size 2.5 mm x 2.5 mm x 2.5 mm for dose calculations. A photon source was positioned in the middle of the water sphere and emitted photons with the energy 400 keV.It was found that the low values and multimodal PDFs for the efficiency gain estimates originated from photons depositing high values of energy in some voxels in the heterogeneous environment. The high energy deposits were due to extremely high statistical weights of photons interacting repeatedly in the highly attenuating tungsten cylinder. When photon histories contributing to the rare events of high energy deposits (outliers) were removed, the PDFs became uni-modal and efficiency gain increased. However, removing outliers will cause results to be biased calling for other techniques to handle the problem with high statistical weights.One way to resolve the problem in the current implementation of the fixed-collision correlated sampling scheme in PTRAN (the MC code used) could be to split photons with high statistical weights into several photons with the same sum weight as the initial photon. The splitting of photons will result in more time consuming simulations in areas with high attenuation coefficients, which may not be the areas of interest. This could be resolved by using Russian roulette, eliminating some of the photons with high statistical weight in such areas.Fixed-collision correlated sampling for Monte Carlo (MC) simulations is a method which can be used in order to shorten the simulation time for brachytherapy treatment planning in a 3D patient geometry. The increased efficiency compared to conventional MC simulation is measured by efficiency gain. However, a previous study showed that, in some cases, PDFs (probability density functions) of estimates of the efficiency gain, simulated using resampling and other MC methods, were multimodal with values below 1. This means that the method was less effective than conventional sampling for these cases. The aims of this thesis were to trace the causes of the multimodal distributions and to propose techniques to mitigate the problem caused by photons with high statistical weights.Two simulation environments were used for the study case, a homogeneous and a heterogeneous environment. The homogenous environment consisted of a water sphere with the radius 100mm. For the heterogeneous environment a cylindrical block of tungsten alloy (diameter 15 mm, height 2.5 mm) was placed in the water sphere. The sphere was divided into an array of cubic voxels of size 2.5 mm x 2.5 mm x 2.5 mm for dose calculations. A photon source was positioned in the middle of the water sphere and emitted photons with the energy 400 keV.It was found that the low values and multimodal PDFs for the efficiency gain estimates originated from photons depositing high values of energy in some voxels in the heterogeneous environment. The high energy deposits were due to extremely high statistical weights of photons interacting repeatedly in the highly attenuating tungsten cylinder. When photon histories contributing to the rare events of high energy deposits (outliers) were removed, the PDFs became uni-modal and efficiency gain increased. However, removing outliers will cause results to be biased calling for other techniques to handle the problem with high statistical weights.One way to resolve the problem in the current implementation of the fixed-collision correlated sampling scheme in PTRAN (the MC code used) could be to split photons with high statistical weights into several photons with the same sum weight as the initial photon. The splitting of photons will result in more time consuming simulations in areas with high attenuation coefficients, which may not be the areas of interest. This could be resolved by using Russian roulette, eliminating some of the photons with high statistical weight in such areas.

During a cardiac cycle the cardiac walls change between contracted and relaxed and the valves open and close in response to pressure changes. This master thesis is a study of the changes in heart movement pattern caused by intravenous injections of Ca2+ or Nitroprusside. At Stanford University radiopaque markers have been surgically implanted in the walls and in the mitral valve of ovine hearts and 3D coordinates for each marker have been constantly measured during the cardiac cycle. By using MatLab, the volume and pressure of the left ventricle and several parameters related to the opening kinematics of the mitral valve have been analyzed. The results show, among others, that both Ca2+ and Nitroprusside reduce the volume and pressure of the left ventricle and that both substances decrease the size of the mitral annular ring. It was also shown that Ca2+ delays the opening of the mitral valve.

In many clinical applications, it is desirable to transmit sensor information wireless. In earlier research, investigation transmit ECG signal using Bluetooth, was performed. However, when Bluetooth has some drawbacks it is of interest to investigate alternative methods, one such method is ZigBee. Bluetooth has higher data rate speed (1Mbps) than ZigBee (250kbps). However, Bluetooth consumes more power. ZigBee uses in applications where low power consumption is important compared to high data rate. For industrial purposes, ZigBee is used in sensors and control unit technology. For medical treatment ZigBee can be used for patient monitoring. The aim of this work is to investigate if it is possible to wireless transmit an ECG signal with ZigBee-technology. The result shows that an ECG signal can be transmitted by using ZigBee. Since ZigBee is designed for low power consumption, the Zigbee-module must be set in passive mode in most of the time.

Conventional Magnetic Resonance Imaging (MRI) is a qualitative method for obtaining images of softtissues in patients. Conventional MRI is the standard method used today and it results in gray-scaleimages in which the different magnetic properties of biological tissues determine the image contrast. However, the magnitude of the measured signal is only relative and therefore not directlycomparable between images. Synthetic MRI is a relatively new technique which can be used to postsynthesizedifferent images based on absolute measurement of several magnetic properties oftissues. Synthetic MRI can therefore provide quantitative information together with the contrastimages. In order to use synthetic MRI clinically an evaluation of the image quality and diagnostic ability isrequired. The purpose of this thesis is to evaluate if synthetic MRI and conventional MRI produceimages with equal contrast. A study was designed and conducted for statistical evaluation of contrast and Contrast-to-Noise Ratio(CNR) generated with different imaging methods. A total of 22 patients were examined using bothconventional MRI and synthetic MRI and the results were pairwise analyzed. The contrast and CNR could not be stated as equal for the imaging methods. Typically the contrastwas higher in the synthetic images for the T1 and T2 weighted images. This was not observed withCNR which suggests that the noise is higher in the synthetic images. The higher contrast obtained insynthetic images resulted in a better separation of different tissues using synthetic MRI. Thesynthetic T2 FLAIR images contained artifacts that are not good for clinical use. However the fact thatthe different imaging methods produce different image quality is not proven to be clinically decisive.