3D-ultrasound-based Organ Localisation During Image-guided External Beam Radiotherapy for the Treatment of Prostate Cancer
Prostate cancer is the most common cancer among men in UK, Europe, and North America.
External beam radiotherapy is a well-established treatment in which a concentrated radiation beam is directed at the prostate from an x-ray source outside the patient. The total radiation dose is delivered in small fractions over about 35 days, however, using modern image-guided and stereotactic delivery methods, it is feasible to use far fewer fractions (hypofractionation). This approach is highly promising but requires high accuracy localisation of the target tissue and surrounding organs at risk to maximise treatment effect and minimise side-effects, which in practice is difficult to achieve due to patient/organ motion. Surgically-implanted prostate markers, imaged using x-rays, are now widely used for localising the prostate during therapy, but inserting these involves an additional invasive procedure. Furthermore, marker-based localisation software does not account for organ deformation, potentially leading to errors. In this project, the feasibility of 3D ultrasound (3DUS) imaging for organ localisation will be investigated, focusing initially on devising a clinically practical method for acquiring 3DUS images in the radiotherapy setting. The remainder of the project will focus on the development and validation of image registration techniques for aligning 3DUS with MRI/CT scans.