Automatic quality assessment of rigid registration of ultrasound images for radiotherapy

点击翻译按钮获取中文摘要

The goal of radiotherapy (RT) is to maximize radiation dose to the tumour while minimizing dose to healthy tissues. The emergence of stereotactic body radiotherapy (SBRT) promises to shorten treatment time from a few weeks to a few days, which is especially significant in remote and rural areas where long commutes are required to attend an RT session. Many organs, such as prostate, liver, lungs and breast, can move substantially during RT due to factors such as breathing, digestion, bladder filling, etc. Therefore, accurate continuous localization of the target is of particular importance in SBRT. Ultrasound is a safe and real-time imaging modality and is commonly used for imaging of soft tissue. It is also significantly less expensive than magnetic resonance (MR) and computed tomography (CT). Tissue tracking with ultrasound can be performed with what is known as image registration in the medical imaging community, which is an active field of research. The tracking information can be used to compensate for motion during treatment. Since the tracking is done automatically, it is important to develop quality assessment (QA) techniques to reduce the chance of missing the target. We propose to develop novel image processing and machine learning techniques that will automatically perform QA of the registration outcome, so that the RT can be temporarily suspended until high quality tracking is restored. Elekta is a world leader in development of advanced RT solutions with strong research and development presence in Canada. The tools developed here may eventually enable more efficient RT methods that significantly shorten the treatment time from daily visits to RT centers from 3-5 weeks to just few days. This is particularly important for individuals who reside in remote areas of Canada, where patients have to be relocated for a long time to receive RT treatment. Furthermore, ultrasound is significantly less expensive and faster compared to MR and CT, and a reliable ultrasound-based tracking system leads to substantial saving for our healthcare system.