Improving quality assurance in radiotherapy

"Radiotherapy is a key method for treating cancer in which high energy radiation is directed at a tumour to destroy it by disrupting DNA replication. However, it is inevitable that surrounding healthy tissue is also irradiated during the process. It is therefore necessary to plan any therapy so as to maximise the tumour's received dose while minimising the dose to the healthy tissue. In this process, known as RT **p**lanning, teams of clinical experts spend a great deal of time developing treatment plans prior to their administration. This process is very time-consuming and can typically take some tens of hours, leading to high costs and limited throughput for the clinic.

A major step in the planning process is the delineation of the tumour and surrounding healthy organs in a medical image scan of the patient, a task known as contouring. **The resultant delineations, called RT s**tructures, are subsequently used to estimate the delivered dose and optimise the treatment plan. Typically, tumour and organ delineation is a laborious manual process.

Manual delineation has inherent variability because the boundaries between organs and tissues may not be clear on the image, and a degree of judgement must be applied by the clinician in deciding where to draw boundaries.

Various commercial automatic contouring (autocontouring) solutions are available to assist in the task of contouring standard anatomy. Typically, these are based on using anatomical mapping to transfer boundaries drawn on a previous image to the current patient image. Such autocontouring systems have been shown to reduce the time required, but more importantly to improve consistency between clinical staff.

Tumours are not standard anatomy and can occur anywhere in the patient. Therefore, the target contour cannot be drawn automatically using typical approaches. However, clinicians still wish to reduce the variability of their contours and ensure high quality treatment.

In this project, we will investigate the commercial and technical feasibility of an approach to address the problem of improving target contouring consistency."