An augmented reality based patient positioning system with applications to breast radiotherapy
French, Samuel Bednar
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A camera system comprised of easily sourced components is presented that demonstrates the feasibility of using an augmented reality display as an aid to patient positioning in radiation therapy. This is accomplished by projecting three-dimensional computed tomography (CT) patient data into a live-video image of a radiation treatment suite. The purpose of this composite image is to aid in the accurate positioning of a patient prior to the delivery of radiation treatment of the breast. A computer code processes a series of calibration images determining the intrinsic and extrinsic camera parameters. The camera parameters are then used to process three-dimensional patient data and project the resulting two-dimensional image into the camera view. The virtual patient (within the live-video image via augmented reality) appears in the planned location relative to the machine couch. The radiation therapist can make adjustments to the patient's position based on visual cues apparent by comparison of the CT projection to the live view. An evaluation of the system in the case of a longitudinal rotation was conducted by way of the imaging of an in-house constructed deformable breast phantom. The results of a positioning study using a CT data set collected from the phantom and projected using the system are reported.