Shear Wave Elastography (SWE) is a medical imaging modality which is able to measure tissue stiffness through the speed of ultrasound-induced shear waves. Pre- vious studies have reviewed the safety aspects of clinical ultrasound, highlighting the harmlessness of the technique. However, in arterial SWE the same type of investiga- tion has not been performed for all applications. The present work aimed to develop an experimental setup for the assessment of acoustic output, which is the pressure field generated by an ultrasound transducer. A second aim was to investigate the safety aspects of SWE with particular attention to arterial applications. In a first step, FOCUS platform was used to simulate and visualize the pressure and intensity distribution around the focal point in three dimensions. Two studies were performed at different focal depths: 15, 20, 25, 30, and 35 mm. In the first study the number of activated elements was kept constant and equal to 64. In the second study the f-number was constant at approximately 1.3. Push widths in three dimensions were compared at different depths, the push dimension did not change in a pronounced way when the f-number was kept constant, but it did when the number of elements was constant. An experimental setup was then developed, made of the programmable ultra- sound system Verasonics with a linear array transducer L7-4 to generate shear waves and a membrane-type hydrophone to analyze the distribution of peak positive pres- sure, peak negative pressure, mechanical index (MI), and spatial peak-time average intensity (ISP T A) at focal depth equal to 35 mm and voltage set at 90 V. The push di- mensions resulting from the hydrophone were compared to FOCUS results, showing similar values especially in x and y direction. To conclude, given MI and ISPTA below the safety thresholds of FDA regula- tions, the present work represents an additional step toward in vivo assessment of arterial stiffness by Shear Wave Elastography.

Electrical bioimpedance measurement is widely used today for monitoring body condition. The applications include and go beyond, body composition assessment, nutritional status evaluation, and cancer detection. The modalities for interpreting the impedance information have also developed quickly over the recent decades from single frequency bioimpedance analysis to spectrum and to images. Bioimpedance is measured by computing the relationship between voltage and current. In a current based bioimpedance measurement system, the stability of current source has a large influence on the performance of the system. This thesis compared three different voltage controlled current sources: enhanced Howland circuit, load-in-the-loop circuit driven by a current conveyor and double operational amplifiers circuit. These circuits were simulated in Multisim and manufactured into prototypes and tested in lab. Effort has also been made to generate and collect signals with digital-to-analog convertor and analog-to-digital convertor. They were controlled by Arduino Uno and impedance was analyzed in Matlab. / Mätning med elektrisk bioimpedans är vida använt idag för medicinsk övervakning. Användningsområden inkluderar bland annat bedömning av kroppssammansättning, uppskattning av nutritionsstatus och detektering av cancer. Modaliteterna för att tolka informationen från elektrisk bioimpedans har också utvecklats snabbt över de senaste årtionden, från analys med en frekvens  till spektrum och bilder. Biompedans erhålls genom att ta fram sambandet mellan ström och spänning. I ett strömbaserat bioimpedans-system har spänningsskällans stabilitet en stor inverkan på systemets prestanda. Det här examensarbetet jämförde tre olika spänningsstyrda strömkällor: en förbättrad Howland-krets, en load-in-the-loop-krets drivs av en ström transportör och en krets med dubbeloperativförstärkare. Dessa kretsar simulerades i Multisim och producerades sedan som prototyper och testades i labb. Försök har även gjorts med att generera och samla in signaler med digital-analog omvandling och analog-digital omvandling. De kontrollerades av Arduino Uno och impedans analyserades i Matlab.

Aortic dissection is a diseased condition of the aorta in which there is an initial tear to the intimal layer propagating in the radial direction initially then causing delamination of the arterial layers creating a false lumen. It is estimated to effect 30 individuals in one million per year. The dissection is fatal when it ruptures, and 90 % of the patients die within three months if not diagnosed. This study presents the first steps towards modeling the propagation of aortic dissection. The aorta was treated as a three-layered fiber-reinforced composite structure, and the Tsai-Wu failure criterion was employed to obtain the 3-D failure surface for the healthy and dissected human aortic media. To be able to obtain Tsai-Wu coefficients, uniaxial tensile tests in the axial, circumferential, and radial direction, and additionally in-plane (axial-circumferential plane) and out-of-plane shear tests in different orientations were performed on human aortic medias. To our knowledge the combination of applied tests and performingof out-of-plane shear tests on aortic tissues is novel. The results showed that the aortic media was the weakest in radial direction under tensile loading. Furthermore, the media was much stronger under out-of-plane shear loading than under in-plane shear loading. In order to consider influences of stress coupling between axial and circumferential directions, an optimal specimen geometry was designed for biaxial tensile testing by the help of finite element analyses. A cruciform geometry with a reduced cross-section in the biaxially loaded zone was found to fit our purposes the best. The preparation protocol to achieve this geometry is currently under investigation. For aortic tissues, all compressive strengths and some biaxial tensile strengths needed to be assumed since they are yet not possible to obtain from mechanical tests. Finally, failure surfaces described by the Tsai-Wu criterion were plotted in 2-D using the analyzed experimental data, with different assumptions in compressive and biaxial tensile strengths.

Radiotherapy (RT) is the most common treatment for cancer. The state-of- the-art modality for RT is the linear accelerator. However, the availability for linear accelerators in the developing world is limited due to costs, infrastructure and need for educated personnel. The development in telecommunica- tions can help to increase the availability by connecting radiation RT-centers and have a central treatment planning unit. Scandinavian Care is a com- pany that builds RT-centers in developing countries and has a project in India where three centers should to be connected. The thesis objectives were to evaluate technical conditions and discuss or- ganizational aspects for remote treatment planning applied on Scandinavian Care’s project in India. The technical conditions were evaluated with two models derived from Swedish case studies. The models were analyzed using a SWOT-model. The organizational aspects were divided into the organiza- tion of medical physicists and three importtant communication channels. The thesis concludes that the technical conditions are possible for the project in India. The best model depends on the frequency of disturbances in the WAN-connection and patient throughput sensitivity. The organization of medical physicists suggests a rotation schedule to promote education, infor- mal communication and variation of tasks. Telemedical conferences and use of software possibilities could ease the feedback. / Strålbehandling är den vanligaste behandlingsmetoden för cancer. Den bästa enheten för strålbehandling är en linjäraccelerator. Däremot är tillgängligheten av linjäracceleratorer i utvecklingsländer begränsad på grund av kostnader, krav på infrastruktur och utbildad personal. Utvecklingen inom telekommunikationer gör det möjligt att öka tillgängligheten genom att koppla ihop strålbehandlingsklinker och exempelvis centralisera dosplaneringen. Scandinavian Care är ett företag som bygger strålbehandlingskliniker i utvecklingsländer och har ett projekt i Indien där tre kliniker är tänkt att sammankopplas. Målet med uppsatsen var att utvärdera tekniska förutsättningar och diskutera organisatoriska aspekter för dosplanering på distans, applicerad på Scandinavian Cares Indienprojekt. De tekniska förutsättningarna utvärderades genom två modeller härledda från svenska fallstudier. Modellerna analyserades med hjälp av en SWOT-analys. De organisatoriska aspekterna delades in i organisationen kring strålfysiker och tre viktiga kommunikationskanaler. Uppsatsen kommer fram till att de tekniska förutsättningarna är genomförbara för Indienprojektet. Den bästa implementeringen beror på hur störningsfrekvensen i WAN- anslutningen påverkar patientflödet. För organisationen av strålfysiker föreslås ett rotationsschema för att främja utbildning, informell kommunikation och variation i arbetet. För att underlätta återkoppling föreslås att utnyttja möjligheterna i mjukvaran och telemedicinska konferenser.

Rapid infusers are used for rapid fluid administration as a part of medical treatment during surgical procedures. The rapid infusers on the market today have proved to present various functional, usability and safety issues for the customers and the problems have not been adequately addressed. This has motivated SLL Innovation to develop a new improved rapid infusion system. The primary reason for considering the development of a rapid infuser device was to meet customer demands and improve safety during the acute situations when the system is to be used. The Quality Function Deployment method was used to describe the design problem systematically and facilitate the development of an improved design. To investigate the users’ issues with existing rapid infusion devices, qualitative semi-structured interviews were conducted individually with hospital staff that had experience with the rapid infuser. Customer requirements were subsequently identified to form a basis for the development process. The results of the study indicated an evident demand for a new product. A three-dimensional (3D) computer aided design (CAD) solution was presented with enhanced properties and features that met the specifications identified. All the customer requirements were addressed in the final result. Safety was the highest rated engineering specification, thus a lot of time and effort was dedicated to solutions that could affect the safety of the system positively. Although the final design is expected to be more efficient and safer than the competition, further research and work is needed before this can be ensured.

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