A patient position guidance system in radiation therapy using augmented reality

With the increased precision in dose delivery provided by highly conformal radiotherapy techniques such as intensity modulated radiotherapy (IMRT), the requirement for accuracy in patient positioning for treatment is emphasised. This system uses augmented reality (AR) to allow the radiation therapist to visually guide the patient during positioning for treatment. It superimposes three-dimensional scan data acquired from the planning CT over a real-time view of the patient, which is obtained from a conventional webcam. The 3D data is positioned relative to AR tracking markers visible to the camera. Throughout development, the system was tested on a 30 cm wooden phantom in place of the patient. A CT scan was performed on the phantom to obtain 3D data, and a small scale test couch was set up to perform registration tests. Modifications to the position of the phantom on the test couch on the order of a millimetre have been visible.