Categorisation of CT Reconstruction Kernels: Using Image Features Directly Extracted from Patient Scans

CT is a versatile medical imaging method to diagnose and monitor patient diseases. However, varying patient characteristics and scan settings create challenges in maintaining consistent image quality, complicating image comparisons, especially across different sources. The reconstruction kernel in CT image reconstruction is a key parameter in...

Modelling X-Ray photon transport through a transformer-based neural network in computed tomography forward projection

Radiotherapy is one of the main treatments for cancer and relies heavily on CT images to calculate radiation dose. With research on radiotherapy moving to adaptive treatments aiming to calculate these doses at real-time speeds while maintaining high precision, a need for accurate CT imaging at comparable real-time speeds has emerged. Currently,...

Image Reconstruction for Dynamic Multi-Pinhole SPECT-imaging using Kernelised Expectation Maximisation

<i><b>Background </b></i>Dynamic SPECT scanning provides a non-invasive way to image the time-dependent distribution of radio-labelled tracers inside living tissue. Beside human medicine, dynamic SPECT also finds its applications in pre-clinical research on small animals. In pre-clinical research, multi-pinhole collimators are used to enable...

Virtual Reduction of Focal Spot Size in Computed Tomography using Collimation

This thesis aimed to validate Beekman's patent on how collimation could virtually reduce the focal spot size of an existing small-animal cone beam Computed Tomography (CT) system to diminish the penumbra effect. The ever-remaining drive to improve the spatial resolution in CT for enhanced image quality introduces the need for small focal spot...

Neural networks for Gamma cameras

In this research the effectiveness of analytical neural networks compared to the maximum likelihood method on the prediction of spatial and DOI positioning of a Gamma detector with a NaI(Tl) scintillator of size 590mm x 470mm x 40mm (x,y,z), with a glass lightguide of size 620mm x 500mm x 4mm and a PMT area of 620mm x 500mm x 40mm with 2-inch...

Assessment of Cerebrovascular Reactivity inPatients with Brain Metastases

Introduction: Radiation is an effective treatment to increase overall mean survival of patients with metastatic brain tumours, however, damage to healthy tissue is inevitable. Radiation can cause dysfunction of the cerebrovasculature which is hypothesised to induce cognitive decline in patients after radiotherapy (RT). A new method, the...

Foetal Imaging: Optimising Lugol’s Solution Staining for CT Scanning

Biomedical researchers and clinicians are interested in (ab)normal foetal development because it can aid in better understanding human anatomy. To capture this foetal development non-destructive three dimensional (3D) imaging techniques like computed tomography (CT) are used. Visualising foetuses remains a challenge however, as foetuses consist...

High-energy multi-pinhole collimator design: Using 3x3 twisted pinhole clusters for high-energy small animal SPECT/PET imaging

With multi-pinhole collimation systems, high resolutions can be reached with both SPECT and PET. Using tracers with higher-energy gamma-photons increases the effects of pinhole edge penetration, decreasing the resolution of the system. This research aims to design a collimator using 3x3 twisted pinhole clusters to be used in the VECTor system....

The application of Deep Learning to improving low count SPECT imaging

Preclinical SPECT systems such as the U-SPECT have been able to achieve sub-half-millimetre spatial resolution with the use of cylindrical pinhole collimators. Utilising this type of collimator comes at the cost of a reduction in the total number of detection events that take place. In order to compensate for this either the activity of the...

Automated Treatment Planning in HDR Brachytherapy for Prostate Cancer

Introduction: High Dose Rate (HDR) Brachytherapy is a radiotherapy modality that involves temporarily introducing a highly radioactive source into the target volume with the use of an applicator. With respect to HDR brachytherapy for prostate cancer, an 192Iridium source is driven into the target volume through catheters implanted into the...

Image Degradation in High Speed Flat-Panel Detector Micro-CT

The aim of this report is to investigate the best possible image quality for high-speed flat-panel detector micro-CT. Specifically, the aim is to investigate the severity of image distortion as a result from the high rotational and acquisition speed. The best possible acquisition mode for high-speed micro-CT is investigated by scanning a ...