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A collimator is a very important part of a gamma camera. There are many types of collimator, but the most common collimator used for general type of imaging is a multihole collimator. Despite its good resolution, the multihole collimator is heavy and bulky, therefore it is difficult to handle. In order to tackle this problem, this thesis introduces a practical model of a lighter wire-mesh collimator and finds the optimal configuration for it. The gamma camera and the collimator are simulated using the MCNPX code. First, we simulate the multihole collimator gamma camera and use the results from these experiments as the standard images to be compared with those produced with the wire-mesh collimator. The sources that we used are a point source, a planar square source and two point sources, and for all the cases, photons at 140keV are simulated. We show that the proposed hardware design in conjunction with image processing can produce images of comparable quality with those of the full collimator with only 39.5% of its weight. The image processing method we use is based on Wiener filtering. Wiener filtering relies on the estimation of the power spectra of the noise and the ideal image. The analysis on the estimation of power spectra is also included in this thesis, and we showed that the combination of the Goodman and Belsher technique with a constant, is the optimum method to be used with the Wiener filtering technique. Key words: Wire-mesh Collimator, Multihole Collimator, Gamma Camera, Wiener Filter.

Endovascular interventions are minimally invasive surgical procedures that are performed to diagnose and treat vascular diseases. These interventions use a combination of long and flexible instruments known as guidewire and catheter. A popular method of developing the skills required to manipulate the instruments successfully is through the use of virtual reality (VR) simulators. However, the interfaces of current VR simulators have several shortcomings due to limitations in the instrument tracking and haptic feedback systems design. A major challenge of developing physics-based training simulations of endovascular interventional procedures is to unobtrusively access the central, co-axial guidewire for tracking and haptics. This work sets out to explore the state of the art, to identify and develop novel solutions to this concentric occlusion problem, and to perform a validation of a proof of concept prototype. This multi port haptic interface prototype has been integrated with a 3-D virtual environment and features novel instrument tracking and haptic feedback actuation systems. The former involves the use of an optical sensor to detect guidewire movements through a clear catheter, whereas the latter utilises the placement of a customised electromagnetic actuator within the catheter hub. During the proof of concept validation process, both systems received positive reviews. Whilst the haptic interface prototype designed in this work has met the original objectives, there are still important aspects which need to be addressed to improve its content and face validity. With further development, the prototype has the potential to evolve and become a significant improvement over the haptic interfaces that exist today.