AbstractID: 7133 Title: Computer-assisted simulator-portal image registration
Comparison of simulation images with portal images is an essential step in the verification of radiation treatment delivery. An image comparison technique based on wavelet-based edge detection combined with chamfer matching is developed. The technique is applied to a set of digitally reconstructed simulator and portal radiographs with known setup errors and to a set of clinical images to assess the feasibility of this technique for computer-assisted image registration. With selection of proper scale and threshold parameters, the edge detector identifies appropriate edges for use in image alignment. For successful image registration, chamfer matching requires that one set of edges be a subset of the other set. Although registration of test images was successful, registration of the clinical images was not, because the images contained too many extraneous edges due to inappropriate image acquisition and image handling technique.
Computer-assisted registration of simulation and portal images is possible, but requires imaging techniques that are free from non-anatomical features and which image all of the relevant anatomy in a consistent manner.