Portable UVB Monitoring System

The Portable UVB Monitoring System is a small, light, inexpensive monitoring system that can be installed on many portable devices in order to help users practice sun safety. This device will display amount of UVB level at the location which then suggests the required amount of SPF that user needs to apply. This device will update the UVB index constantly so user can rely on this device to alert them if the exposure is dangerous or if they are using the wrong level of SPF. The PUMS device is easy to use and helps every user experience safe sun exposure during all seasons and will provide outdoor workers with a reliable reference to UVB rays.&nbsp

Evaluation of wave delivery methodology for brain MRE: Insights from computational simulations

Purpose MR elastography (MRE) of the brain is being explored as a biomarker of neurodegenerative disease such as dementia. However, MRE measures for healthy brain have varied widely. Differing wave delivery methodologies may have influenced this, hence finite element-based simulations were performed to explore this possibility. Methods The natural frequencies of a series of cranial models were calculated, and MRE-associated vibration was simulated for different wave delivery methods at varying frequency, using simple isotropic viscoelastic material models for the brain. Displacement fields and the corresponding brain constitutive properties estimated by standard inversion techniques were compared across delivery methods and frequencies. Results The delivery methods produced widely different MRE displacement fields and inversions. Furthermore, resonances at natural frequencies influenced the displacement patterns. Consequently, some delivery methods led to lower inversion errors than others, and the error on the storage modulus varied by up to 11% between methods. Conclusion Wave delivery has a considerable impact on brain MRE reliability. Assuming small variations in brain biomechanics, as recently reported to accompany neurodegenerative disease (e.g., 7% for Alzheimer's disease), the effect of wave delivery is important. Hence, a consensus should be established on a consistent methodology to ensure diagnostic and prognostic consistency

Validation of the UBC powered upper limb orthosis simulator

Paresis in the upper limb is a condition that leaves the users with flail or severely weakened arms, prohibiting them from being able to perform common everyday tasks such as reaching and grasping objects, eating, drinking, cooking, performing personal hygiene, etc. The UBC Powered Upper Limb Orthosis (UBC-PULO) is a wearable, highly-functional assistive device that supports and restores the functions necessary to one entire arm, enabling users to perform high-priority daily living tasks. Previous work towards achieving this goal has included: developing user specifications, identifying desired tasks and arm motions required to perform them, establishing design specifications and evaluation criteria, developing a control strategy along with hardware and software for the device, and completing the construction of an orthosis prototype with user control interfaces. Recently, a virtual reality simulation environment (VRSE) has been developed for the UBC-PULO which models the control system and electro-mechanical exoskeleton. The VRSE is a tool that can be used for optimization of the control system and testing current or new exoskeleton designs, and has the potential for screening and training of potential users but only if it properly mimics the real physical orthosis device. Therefore, the final objective of this research is to validate the VRSE against the physical prototype. The steps needed to achieve this final objective in the UBC-PULO project include reviewing the state of the current prototype, performing work to commission the device and interfaces, development and implementation of an experimental setup to allow for validation, development of representative control input parameters for proper simulation of the physical device, and testing to validate the VRSE against the physical prototype. The research work described in this thesis responds to these needs by performing a review of the current electrical and mechanical state of the prototype, proposing and implementing a range of design improvements necessary for commissioning the prototype system, development and implementation of a completely new electronic platform along with the necessary software, and performing tests to validate the VRSE.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat

Development of a desktop high-resolution MRI for microflow visualization

Research in lab-on-a-chip (LOC) technology involving microfluidics is a growing field aiming at the development of miniaturized biomedical systems with rich functionality. In order to design effective LOC microfluidic systems, the flow fields and the fluids inside LOC devices need to be carefully characterized. High-resolution magnetic resonance imaging (MRI) offers a powerful non-intrusive technology for this application. In this thesis, the design and implementation of a prototype for a desktop high-resolution MRI instrument, consisting of a magnet, gradient coils, gradient amplifiers, and radio frequency (RF) electronics, is presented. To reduce the size and cost of this MRI instrument, a permanent magnetic configuration with a magnetic flux density of 0.6 T is designed with off-the-shelf NdFeB permanent magnets. The coils of the triaxial gradient module are developed using a novel lithography technique. This gradient module is capable of generating gradient fields as high as 2.83 T/m with custom made current amplifiers. The radio frequency (RF) probe is integrated with the gradient module and is connected to the RF electronics which are made using off-the-shelf components. Pulse sequences and signal processing for acquiring static images and velocity profiles are described. The performance of this instrument in terms of static and dynamic image resolution are presented. As a preliminary test, the velocity profile of water flowing inside a small tube was measured with a nominal resolution of 40 μm. The instrument is designed for a static resolution of better than 30 μm and a velocity resolution better than 50 μm/s. Improvements to the current instrument in addition to theoretical limitations are also detailed.Applied Science, Faculty ofElectrical and Computer Engineering, Department ofGraduat

Magnetic resonance elastography of prostate cancer

This work presents new approaches to in-vivo and ex-vivo human prostate cancer imaging using magnetic resonance elastography (MRE) – a method to non-invasively image tissue elasticity using magnetic resonance imaging (MRI). From a clinical perspective, stiffness correlates with underlying tissue disease processes and has been traditionally probed with palpation. Thus, diagnosis based on mechanical properties may have great implications in terms of staging of prostate cancer, monitoring disease progression, treatment planning and post treatment follow up. In MRE, mechanical shear waves generted by an external transducer are imaged using an MRI scanner. From the acquired wave field it is possible to reconstruct mechanical properties such as the elastic modulus based on the wave equation. In this work two MR compatible trans-perineal transducers are developed for imaging of the human prostate on a 3T MR scanner. A new MRI pulse sequence is also developed to acquire the three dimensional wave field induced by these transducers. The methods are validated in quality assurance phantoms and volunteer repeatability studies. The system is used for a patient study and the results are compared to the gold standard (whole-mount histopathology marked with Gleason score). Similarly, a transducer is developed for ex-vivo prostate studies on a 7T MR scanner. After validation, prostate specimens of patients are examined and the results are compared to the Gleason score. The overall conclusion are: (i) trans-perineal excitation is well tolerated by the subjects, (ii) the transducers do not interfere with the MR acquisition, (iii) the three dimensional wave field are successfully captured using the new pulse sequence, (iv) phantom validation studies prove that the methods are in fact repeatable and that the stiffness values match with the manufacturer’s specifications, (v) patient motion and the standing wave pattern degrade the repeatability of the reconstructed images, (vi) the prostate gland stands out in the stiffness and shear strain images, (vii) the central gland and in particular the transition zone are stiffer than the peripheral zone, (viii) cancer could indeed be detected with MRE with an area under the receiver-operator-curve of approximately 0.7, and finally (ix) the chemical fixation process degrades the stiffness contrast.Applied Science, Faculty ofGraduat